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Nuclear waste containers: the problem of corrosion in copper canisters

The court said no to the application because it considered that there were problems with the copper canister that had to be resolved now and not later. 

the UK’s National Nuclear Laboratory (NNL) is to carry out an expert peer review of a Canadian research programme on microbiologically influenced corrosion of canisters that will be used to dispose of used nuclear fuel.

The Copper Corrosion Conundrum  No2Nuclear Power  http://www.no2nuclearpower.org.uk/wp/wp-content/uploads/2018/03/NuClearNews_No105.pdf

The Swedish Environmental Court has rejected the Nuclear Waste Company SKB’s license application for a final repository for spent nuclear fuel in Forsmark, Sweden. This is a huge triumph for safety and environment – and for the Swedish NGO Office for Nuclear Waste Review (MKG), the Swedish Society for Nature Conservation (SSNC), and critical scientists. Now it is up to the Swedish government to make a final decision.

The Environmental Court took into consideration viewpoints from all parties in the case, including scientists who have raised concerns about disposing spent nuclear fuel in copper canisters. During the legal proceedings, the Swedish NGO Office for Nuclear Waste Review (MKG) and the Swedish Society for Nature Conservation (SSNC) presented the shortcomings of this method of disposal. For many years, the environmental organisations have been arguing that the Nuclear Waste Company SKB need to listen to critical scientists, and investigate alternative disposal methods, especially the possibility of developing a very deep boreholes disposal system. (1) Johan Swahn, Director at MKG said:

“Several independent researchers have criticized both the applied method and the selected site. There is a solid documentation base for the Environmental Court’s decision. It is hard to believe the Swedish Government’s conclusions will be any different from the Court’s.”

MKG has made an unofficial translation into English of the Environmental Court opinion. (2)

The court said no to the application because it considered that there were problems with the copper canister that had to be resolved now and not later. The translation shows the courts judicial argumentation and why it decided not to accept the regulator – the Swedish Radiation Safety Authority’s (SSM’s) opinion that the problems with the integrity of the copper canister were not serious and could likely be solved at a later stage in the decision-making process. The court is quite clear in its statement and argumentation:

“The Land and Environmental Court finds that the environmental impact assessment meets the requirements of the Environmental Code and can therefore be approved. All in all, the investigation meets the high standards set out in the Environmental Code, except in one respect, the safety of the canister.” (Emphasis added)

“The investigation shows that there are uncertainties, or risks, regarding how much certain forms of corrosion and other processes can impair the ability of the canister to contain the nuclear waste in the long term. Overall, these uncertainties about the canister are significant and have not been fully taken into account in the conclusions of SKB’s safety analysis. The Land and Environmental Court considers that there is some leeway for accepting further uncertainties. The uncertainties surrounding certain forms of corrosion and other processes are, however, of such gravity that the Court cannot, based on SKB’s safety analysis, conclude that the risk criterion in the Radiation Safety Authority’s regulations has been met. In the context of the comprehensive risk assessment required by the Environmental Code, the documentation presented to date does not provide sufficient support for concluding that the final repository will be safe in the long term.” (Emphasis added)

The court says that the application is only permissible if the nuclear waste company SKB:

“…produces evidence that the repository in the long term will meet the requirements of the Environmental Code, despite remaining uncertainties regarding how the protective capability of the canister may be affected by: a. corrosion due to reactions in oxygen-free water; b. pit corrosion due to reaction with sulphide, including the contribution of the sauna effect to pit corrosion; c. stress corrosion due to reaction with sulphide, including the contribution of the sauna effect to stress corrosion; d. hydrogen embrittlement; e. radioactive radiation impact on pit corrosion, stress corrosion and hydrogen embrittlement.”

The main difference between the court’s and the regulator’s decision-making was that the court decided to rely on a multitude of scientific sources and information and not only on the material provided by SKB. It had also been uncovered that the main corrosion expert at SSM did not want to say yes to the application at this time that may have influenced the court’s decision-making. In fact there appear to have been many dissenting voices in the regulator despite the regulator’s claim in the court that a united SSM stood behind its opinion.

The court underlines in its opinion that the Environmental Code requires that the repository should be shown to be safe at this stage in the decision-making process, i.e. before the government has its say. The court says that some uncertainties will always remain but it sees the possible copper canister problems as so serious that it is not clear that the regulator’s limits for release of radioactivity can be met. This is a reason to say no to the project unless it can be shown that the copper canister will work as intended. The copper canister has to provide isolation from the radioactivity in the spent nuclear fuel to humans and the environment for very long time-scales.

It is still unclear how the process will proceed. The community of Östhammar has cancelled the referendum on the repository, as there will be no question from the government in the near future. The government has set up a working group of civil servants to manage the government’s handling of the opinions delivered by the court and SSM. SKB has said that it is preparing documentation for the government to show that there are no problems with the canister. Whether the government thinks this will be enough remains to be seen. This is likely not what the court had in mind. The government would be wise to make a much broader review of the issue. There is a need for a thorough judicial review on the governmental level in order to override the court’s opinion. Otherwise the government’ decision may not survive an appeal to the Supreme Administrative Court.

There are eminent corrosion experts who believe that copper is a bad choice as a canister material. There is also increasing experimental evidence that this is the case. The court’s decision shows the importance of democratic and open governance in environmental decisionmaking. It is important that the continued decision-making regarding the Swedish repository for spent nuclear is transparent and multi-faceted. (3)

Copper Canisters The canister has to enclose the nuclear waste for a very long; it is the final repository’s primary safety function. The canister has a 50 mm thick copper shell with an insert of cast iron. The canister must withstand corrosion and mechanical stress.

The investigation on the capability of the canister is extensive and involves complex technical and scientific issues. These include groundwater chemistry, corrosion processes, as well as creep and hydrogen embrittlement (this latter affects the mechanical strength of the canister). However, the parties taking part in the court proceedings disagreed on several issues crucial to the final repository’s long-term security.

The Land and Environmental Court considered the following uncertainties regarding the canister to be most important in the continued risk assessment:

  • 1. General corrosion due to reaction in oxygen-free water. The parties have different views on scientific issues surrounding this kind of corrosion. The Court found that there is considerable uncertainty on this topic that has not been taken account of in SKB’s safety analysis
  • .· 2. Local corrosion in the form of pit corrosion due to reaction with sulphide. The Court found that there is significant uncertainty regarding pit-corrosion due to reaction with sulphide. This uncertainty has not been included in the safety analysis. In addition, there is uncertainty about the sauna effect, which may have an amplifying effect on pit corrosion.
  • · 3. Local corrosion in the form of stress corrosion due to reaction with sulphide. The Court found that there is significant uncertainty regarding stress corrosion due to reaction with sulphide. This uncertainty has not been included in the safety analysis. In addition, there is uncertainty about the sauna effect, which may have an amplifying effect on stress corrosion.
  • · 4. Hydrogen embrittlement is a process that affects the mechanical strength of the canister. The Court found that significant uncertainty regarding hydrogen embrittlement remains. This uncertainty has not been taken account of in the safety analysis.
  •  · 5. The effect of ionizing radiation on pit corrosion, stress corrosion and hydrogen embrittlement. There is significant uncertainty regarding ionizing radiation impact on pit corrosion, stress corrosion and hydrogen sprays. This uncertainty has been included to a limited extent in the safety assessment.

Meanwhile, the UK’s National Nuclear Laboratory (NNL) is to carry out an expert peer review of a Canadian research programme on microbiologically influenced corrosion of canisters that will be used to dispose of used nuclear fuel. The NNL has been contracted by Canada’s National Waste Management Organisation (NWMO) to review its work on the potential for corrosion of the copper-clad canisters. The NWMO is responsible for designing and implementing the safe, long-term management of Canada’s used nuclear fuel under a plan known as Adaptive Phased Management. This requires used fuel to be contained and isolated in a deep geological repository, with a comprehensive process to select an informed and willing host for the project.

The used fuel will be isolated from the environment using a series of engineered barriers. Fuel elements comprise ceramic fuel pellets, which are themselves highly durable, contained inside corrosion-resistant zircaloy tubes to make fuel elements. Bundles of fuel elements are placed into large, durable copper-coated steel containers which are designed to contain and isolate used nuclear fuel in a deep geological repository, essentially indefinitely. The canisters will be placed in so-called “buffer boxes” containing by bentonite clay, providing a fourth barrier.

World Nuclear News reports that although copper is highly resistant to corrosion, under anoxic conditions – that is, where no oxygen is present – sulphate-reducing bacteria have the potential to produce sulphide, which can lead to microbiologically induced corrosion (MIC) of copper. Waste management organisations and regulators therefore need to understand the levels of sulphide that will be present in a geological disposal facility, to understand its potential to migrate to the canister surface and the potential for it to cause copper corrosion, the NNL said.

The NWMO has been actively developing computer models that will be used to evaluate the potential for MIC once a disposal site has been selected, and has selected the NNL to carry out a peer review of its work because of the UK laboratory’s expertise in the biogeochemical processes that could affect repository performance and in developing computer modelling techniques that simulate the effects of sulphate-reducing bacteria. The work is linked closely with NNL’s participation in the European Commission Horizon-2020 MIND (Microbiology in Nuclear waste Disposal) project. (4

March 14, 2018 Posted by | Reference, Sweden, wastes | 1 Comment

MIT’s $millions plan for small nuclear fusion station

MIT Receives Millions to Build Fusion Power Plant Within 15 Years https://gizmodo.com/mit-receives-millions-to-build-fusion-power-plant-withi-1823644634?IR=T   Ryan F. Mandelbaum 10 Mar 18 Nuclear fusion is like a way-more-efficient version of solar power—except instead of harnessing energy from the rays of a distant sun, scientists create miniature suns in power plants here on Earth. It would be vastly more efficient, and more importantly, much cleaner, than current methods of energy production. The main issue is that actually realizing fusion power has been really difficult.

But MIT has announced yesterday that it is working with a new private company called Commonwealth Fusion Systems (CFS) to make nuclear fusion finally happen. CFS recently attracted a $50 million investment from the Italian energy company Eni, which it will use to fund the development.

The goal? “The 15-year timeline is to get a device that puts 200 megawatts on the grid,” CFS CEO and MIT grad Robert Mumgaard told Gizmodo. “That’s a small city.”

Nuclear fusion is the process by which two hydrogen atoms are fused together into helium. This process results in the release of lots of energy. Scientists have been chasing fusion for a long time, perhaps since the 1950s. But there have been technological roadblocks, mainly making a device that outputs more energy than it takes to run. Another fusion device under construction in Europe called ITER, for example, should be ready by 2035 but is far over budget. The US Senate has attempted to pull out of the project, reports Nature.

MIT’s “tokamak” fusion reactor seems to promise much cheaper fusion power. It relies on a non-traditional, higher-temperature superconductor called ytterbium-barium-copper-oxide, a kind of cuprate, to allow electricity to flow efficiently without resistance. These produce strong magnetic fields and high pressures in plasma that confine the fusion reactions inside of the device. The sun confines its own reactions with its immense gravity.

The MIT group has been researching the device for a few years. This infusion of capital should allow them to build magnets four times stronger in the next three years. The planned device, called Sparc, will be a 65th of ITER’s size but release a fifth the power, according to an email sent by MIT’s press office.

  Of course, there are challenges. Martin Greenwald, deputy director of MIT’s Plasma Science and Fusion Center, told Gizmodo that they have yet to actually develop these magnets and integrate them into such a machine. They will also need to learn how to build and operate the device, and bring it to a position that it can actually enter the market.

It’s important to note that fusion is way different from fission, the process that powers current nuclear power plants. Fusion can’t cause an explosive runaway chain reaction without some sort of fissile material, and rather than using uranium like fission does, it’s water and lithium in, helium out. This also cuts down on nuclear weapons risks. “There’s no reason to have fissile materials around fusion plants,” said Greenwald. “If you do, you’re up to no good.”

Some, like the folks at the Bulletin of the Atomic Scientists, still worry that the excess neutrons produced in fusion could lead to radioactive waste or contaminants, as well as high costs.

Nature points out that there are plenty others are in the fusion-with-high-temperature-superconductors game, too. Princeton has its own tokamak, and there’s a British company called Tokamak Energy using a similar device to produce fusion energy. But all of the cash towards the MIT effort is significant.

“If MIT can do what they are saying—and I have no reason to think that they can’t — this is a major step forward,” Stephen Dean, head of Fusion Power Associates, in Maryland, told Nature.  Perhaps all fusion power needed to become reality was, well, a lot of money. Mumgaard said that CFS’ collaboration with MIT will “provide the speed to take what’s happening in the lab and bring it to the market.”

March 10, 2018 Posted by | Reference, technology, USA | Leave a comment

Gender and Radiation: Women and Children Require More Protection

 https://mariannewildart.wordpress.com/2018/03/08/gender-and-radiation-women-and-children-require-more-protection/

ON  BY MARIANNEWILDART
Today is International Women’s Day  “a time to reflect on progress made, to call for change and to celebrate acts of courage and determination by ordinary women who have played an extraordinary role in the history of their countries and communities.” 

There are many such women in the anti-nuclear movement.  For example..

Mary Olson is the Founder of the Gender and Radiation Impact Project and is clear her life’s mission is to bring to light the disproportionate impact of radiation on girls and women. Over her long career, Olson has studied radiation health consequences with some of the leading radiation researchers of the 20 th Century including Rosalie Bertell, Alice Stewart, Helen Caldicott and Wing, and was featured in the educational film “ The Ultimate Wish: Ending the Nuclear Age” Through her work as a staff biologist and policy analyst at Nuclear Information and Resource Service , she has worked for decades to improve public policy on highly radioactive spent nuclear fuel and plutonium
Below is an excellent fact sheet from the Nuclear Information and Resource Service

Women & Children Require More Protection from

Ionizing Radiation than Men

NAS Findings: Adult Males are Group Most
Resistant to getting Cancer from Radiation
There is no safe dose of ionizing radiation: any
exposure of living cells to sub-atomic particles
(alpha, beta, neutron) or waves of energy (gamma,
X-ray) ejected from unstable radioactive atoms
has the potential to trigger cancer in people.i
Men get cancer from exposure to radiation, and
men die from that cancer, however, for reasons
not yet fully understood , fewer males get cancer
and fewer of them die from it compared to
females of the same age at the same level of
radiation exposure. The difference is not small:
for every two men who get cancer, three women
suffer this disease. These findings of physical
difference (not based on behavior) of 40% — 60%
more cancer in women compared to men come
from the (US) National Academy of Sciences
(NAS), Biological Effects of Ionizing Radiation
(BEIR) Report number VII, published in 2006 ii
It has been common knowledge that children’s
bodies are the most vulnerable to radiation
impacts, but from BEIR VII we also learn that
little girls (age 0 — 5 years) are twice as likely to
suffer harm from radiation (defined in BEIR VII
as cancer) as little boys in the same age group. iii
In October 2011, NIRS published a briefing paper
Atomic Radiation is More Harmful to Women iv
containing more details about these findings. The
numbers in the BEIR VII tables are the source of
this new information. Gender difference is not
discussed in the report text.
Not every dose of radiation results in detectable
harm–cells have repair
mechanisms. However,
every exposure carries the potential for harm; and
that potential is tied to age of exposure and
gender.
Radiation Exposure Standards Based on Adult
Male Body
While we cannot see or
otherwise detect radiation with
our senses, we can see its
damage….
When the  first regulations were made, it was because
soldiers and scientists in the U.S. (virtually all
male to begin with) were working on building
nuclear weapons. The first standards were
“allowable” limits for exposing these men to a
known hazard.
Radiation Levels v Dose
Geiger counters and other devices can detect
levels of radiation and concentrations of
radioactivity.  It is much more difficult to say how much of that energy has impacted a living body (dose). Dose is calculated based on body size, weight, distance from the source and assumptions about biological impact. Gender is not factored in a typical determination of a dose. Historically the “dose receptors” were male, and were of a small age range. It is somewhat understandable that the “Reference Man”v was based on a “Standard Man”–a guy of a certain height, weight and age. Clearly such assumptions are no longer valid when there is such a striking gender difference– 40% to 100% greater likelihood of cancer or cancer death (depending on the age) for females, compared to males.vi

Not Only Cancer

Radiation harm includes not only cancer and leukemia, but reduced immunity, reduced fertility, increases in other diseases including heart disease, birth defects including heart defects, other mutations (both heritable and not). When damage is catastrophic to a developing embryo, spontaneous abortion or miscarriage of a pregnancy may result.vii

Gender Mechanism Not Yet Described

Perhaps the reason that the National Academy of Sciences does not discuss the fact that gender has such a large impact on outcome of exposure to radiation is that the causal  mechanism is not yet described.

Dr. Rosalie Bertell, one of the icons of research and education on radiation health effects, suggests that one basis may be that the female body has a higher percentage of reproductive tissue than the male body. Dr. Bertell points to

studies showing reproductive organs and tissues are more sensitive to radiation. Nonetheless, Dr. Bertell is clear: “While research is clearly needed, we should PROTECT FIRST.”

Ignoring Gender Results in More Harm

The NAS BEIR VII findings show that males of all ages are more resistant to radiation exposure than females, and also that all children are more vulnerable than adults. The only radiation standard certain to protect everyone is zero. Given the fact that there is no safe dose of radiation, it is an appropriate goal. Any additional exposure above unavoidable naturally occurring radiation should include full disclosure and concurrence of the individual. It is time to adopt non-radioactive practices for making energy, peace, security and healing.

03/10/2012 Mary Olson, NIRS Southeast maryo@nirs.org / 828-252-8409

i See http://www.nirs.org/radiation/
ii BEIR VII, Table 12D‐3 page 312, National Academy Press (Washington, DC) 2006.
iii BEIR VII page 311, Table 12‐D 1.
iv NIRS: Atomic Radiation is More Harmful to Women http://www.nirs.org/radiation/radhealth/radiationwomen.p df
vICRP Publication 23: Reference Man: Anatomical, Physiological and Metabolic Characteristics, 1st Edition

vi IEER: The use of Reference Man in Radiation Protection Standards and Guidance with Recommendations for Change http://www.ieer.org/reports/referenceman.pdf
vii Non‐cancer health effects are documented in classic works of John Gofman, for instance Radiation and Human Health (Random House 1982) and digital documents available: http://www.ratical.org/radiation/overviews.html#CNR and Dr. Rosalie Bertell’s classic work No Immediate Danger, Summer Town Books, 1986.

March 9, 2018 Posted by | radiation, Reference, women | Leave a comment

Thorium ‒ a better fuel for nuclear technology? 

  Thorium ‒ a better fuel for nuclear technology? Nuclear Monitor,   by Dr. Rainer Moormann  1 March 2018 An important, detailed critique of thorium by Dr. Rainer Moormann, translated from the original German by Jan Haverkamp. Dr. Moormann concludes:

“The use of technology based on thorium would not be able to solve any of the known problems of current nuclear techniques, but it would require an enormous development effort and wide introduction of breeder and reprocessing technology. For those reasons, thorium technology is a dead end.”

Author: Dr. Rainer Moormann, Aachen (r.moormann@gmx.de) Thorium is currently described by several nuclear proponents as a better alternative to uranium fuel.

Thorium itself is, however, not a fissile material. It can only be transformed into fissile uranium-233 using breeder and reprocessing technology. It is 3 to 4 times more abundant than uranium.

Concerning safety and waste disposal there are no convincing arguments in comparison to uranium fuel. A severe disadvantage is that uranium-233 bred from thorium can be used by terror organisations for the construction of simple but high-impact nuclear explosives. Thus development of a thorium fuel cycle without effective denaturation of bredfissile materials is irresponsible.

Introduction

Thorium Introduction 

Thorium (Th) is a heavy metal of atomic number 90

(uranium has 92). It belongs to the group of actinides, is

around 3 to 4 times more abundant than uranium and is

radioactive (half-life of Th-232 as starter of the thorium

decay-chain is 14 billion years with alpha-decay). There

are currently hardly any technical applications. Distinctive

is the highly penetrating gamma radiation from its decaychain

(thallium-208 (Tl-208): 2.6 MeV; compared to

gamma radiation from Cs-137: 0.66 MeV). Over the past

decade, a group of globally active nuclear proponents is

recommending thorium as fuel for a safe and affordable

nuclear power technology without larger waste and

proliferation problems. These claims should be submitted

to a scientific fact check. For that reason, we examine

here the claims of thorium proponents.

Dispelling Claim 1: The use of thorium expands the

availability of nuclear fuel by a factor 400  

Thorium ‒ a better fuel for nuclear technology? Nuclear Monitor,   by Dr. Rainer Moormann  1 March 2018

Thorium itself is not a fissile material. It can, however, be

transformed in breeder reactors into fissile uranium-233

(U-233), just like non-fissile U-238 (99.3% of natural

uranium) can be transformed in a breeder reactor to fissile

plutonium. (A breeder reactor is a reactor in which more

fissile material can be harvested from spent nuclear fuel

than present in the original fresh fuel elements. It may be

sometimes confusing that in the nuclear vocabulary every

conventional reactor breeds, but less than it uses (and

therefore it is not called a breeder reactor).)

For that reason, the use of thorium presupposes the use

of breeder and reprocessing technology. Because these

technologies have almost globally fallen into disrepute, it

cannot be excluded that the more neutral term thorium is

currently also used to disguise an intended reintroduction

of these problematic techniques.

The claimed factor 400: A factor of 100 is due to the

breeder technology. It is also achievable in the uraniumplutonium

cycle. Only a factor of 3 to 4 is specific to

thorium, just because it is more abundant than uranium

by this factor…….

March 5, 2018 Posted by | 2 WORLD, ENERGY, Reference, thorium | Leave a comment

It’s a myth that thorium nuclear reactors were ever commercially viable

Dispelling Claim 2: Thorium did not get a chance in the  nuclear energy development because it is not  usable for military purposes   Thorium ‒ a better fuel for nuclear technology? Nuclear Monitor,   by Dr. Rainer Moormann  1 March 2018

In the early stages of nuclear technology in the USA (from 1944 to the early 1950s), reprocessing technology was not yet well developed. Better developed were graphite moderated reactors that used natural uranium and bred plutonium.

For the use of thorium (which, other than uranium, does not contain fissile components), enriched uranium or possibly plutonium would have been indispensable.

Initially, neither pathway for thorium development was chosen because it would have automatically reduced the still limited capacity for military fissile materials production. (Thorium has a higher capture cross section for thermal (that means slow) neutrons than U-238. For that reason, it needs as fertile material in reactors a higher fissile density than U-238.)

Only when the US enrichment capacity at about 1950 delivered sufficient enriched uranium, the military and later civil entry into thorium technology started: in 1955 a bomb with U-233 from thorium was exploded, and a strategic U-233 reserve of around 2 metric tons was created. The large head-start of the plutonium bomb could not be overtaken any more, and plutonium remained globally the leading military fission material (although, according to unconfirmed sources, Indian nuclear weapons contain U-233).

The US military research concluded in 1966 that U-233 is a very potent nuclear weapon material, but that it offers hardly any advantages over the already established plutonium. Because light water reactors with low-enriched uranium (LEU) were already too far developed, thorium use remained marginal also in civil nuclear engineering: for instance, the German “thorium reactor” THTR-300 in Hamm operated only for a short time, and in reality it was a uranium reactor (fuel: 10% weapon-grade 93% enriched U-235 and 90% thorium) because the amount of energy produced by thorium did not exceed 25%.

 

March 5, 2018 Posted by | 2 WORLD, business and costs, Reference, spinbuster, thorium | Leave a comment

The weapons proliferation risks of thorium nuclear reactors

Dispelling Claim 3: Thorium use has hardly any proliferation risk   Thorium ‒ a better fuel for nuclear technology? Nuclear Monitor,   by Dr. Rainer Moormann  1 March 2018

The proliferation problem of Th / U-233 needs a  differentiated analysis ‒ general answers are easily misleading. First of all, one has to assess the weapon capability of U-233. Criteria for good suitability are a low critical mass and a low rate of spontaneous fission. The critical mass of U-233 is only 40% of that of U-235, the critical mass of plutonium-239 is around 15% smaller than for U-233. A relatively easy to construct nuclear explosive needs around 20 to 25 kg U-233.

The spontaneous fission rate is important, because the neutrons from spontaneous fission act as a starter of the chain reaction; for an efficient nuclear explosion, the fissile material needs to have a super-criticality of at least 2.5 (criticality is the amount of new fissions produced by the neutrons of each fission.)

When, because of spontaneous fissions, a noticeable chain reaction already starts during the initial conventional explosion trigger mechanism in the criticality phase between 1 and 2.5, undesired weak nuclear explosions would end the super-criticality before a significant part of the fissile material has reacted. This largely depends on how fast the criticality phase of 1 to 2.5 is passed. Weapon plutonium (largely Pu-239) and moreover reactor plutonium have – different from the mentioned uranium fission materials U-235 and U-233 – a high spontaneous fission rate, which excludes their use in easy to build bombs.

More specifically, plutonium cannot be caused to explode in a so-called gun-type fission weapon, but both uranium isotopes can. Plutonium needs the far more complex implosion bomb design, which we will not go into further here. A gun-type fission weapon was used in Hiroshima – a cannon barrel set-up, in which a fission projectile is shot into a fission block of a suitable form so that they together form a highly super-critical arrangement.   Here, the criticality phase from 1 to 2.5 is in the order of magnitude of milliseconds – a relatively long time, in which a plutonium explosive would destroy itself with weak nuclear explosions caused by spontaneous fission.

One cannot find such uranium gun-type fission weapons in modern weapon arsenals any longer (South Africa’s apartheid regime built 7 gun-type fission weapons using uranium-235): their efficiency (at most a few percent) is rather low, they are bulky (the Hiroshima bomb: 3.6 metric tons, 3.2 meters long), inflexible, and not really suitable for carriers like intercontinental rockets.

On the other hand, gun-type designs are highly reliable and relatively easy to build. Also, the International Atomic Energy Agency (IAEA) reckons that larger terror groups would be capable of constructing a nuclear explosive on the basis of the gun-type fission design provided they got hold of a sufficient amount of suitable fissile material.1

Bombs with a force of at most 2 to 2.5 times that of the Hiroshima bomb (13 kt TNT) are conceivable. For that reason, the USA and Russia have tried intensively for decades to repatriate their world-wide delivered highly enriched uranium (HEU).

A draw-back of U-233 in weapon technology is that – when it is produced only for energy generation purposes – it is contaminated with maximally 250 parts per million (ppm) U-232 (half-life 70 years).2 That does not impair the nuclear explosion capability, but the uranium-232 turns in the thorium decay chain, which means ‒ as mentioned above ‒ emission of the highly penetrating radiation of Tl-208. A strongly radiating bomb is undesirable in a military environment – from the point of view of handling, and because the radiation intervenes with the bomb’s electronics.

In the USA, there exists a limit of 50 ppm U-232 above which U-233 is no longer considered suitable for weapons.

Nevertheless, U-232 does not really diminish all proliferation problems around U-233. First of all, simple gun-type designs do not need any electronics; furthermore, radiation safety arguments during bomb construction will hardly play a role for terrorist organisations that use suicide bombers.

Besides that, Tl-208 only appears in the end of the decay chain of U-232: freshly produced or purified U-233/U-232 will radiate little for weeks and is easier to handle.2 It is also possible to suppress the build-up of uranium-232 to a large extent, when during the breeding process of U-233 fast neutrons with energies larger than 0.5 MeV are filtered out (for instance by arranging the thorium in the reactor behind a moderating layer) and thorium is used from ore that contains as little uranium as possible.

A very elegant way to harvest highly pure U-233 is offered by the proposed molten salt reactors with integrated reprocessing (MSR): During the breeding of U-233 from thorium, the intermediate protactinium-233 (Pa-233) is produced, which has a half-life of around one month. When this intermediate is isolated – as is intended in some molten salt reactors – and let decay outside the reactor, pure U-233 is obtained that is optimally suited for nuclear weapons.

An advantage of U-233 in comparison with Pu-239 in military use is that under neutron irradiation during the production in the reactor, it tends to turn a lot less into nuclides that negatively influence the explosion capability. U-233 can (like U-235) be made unsuitable for use in weapons by adding U-238: When depleted uranium is already mixed with thorium during the feed-in into the reactor, the resulting mix of nuclides is virtually unusable for weapons.

However, for MSRs with integrated reprocessing this is not a sufficient remedy. One would have to prevent separation of protactinium-233.9

The conclusion has to be that the use of thorium contains severe proliferation risks. These are less in the risk that highly developed states would find it easier to lay their hands on high-tech weapons, than that the bar for the construction of simple but highly effective nuclear explosives for terror organisations or unstable states will be a lot lower.

 

March 5, 2018 Posted by | Reference, spinbuster, thorium, weapons and war | Leave a comment

Thorium nuclear reactors: no safer than conventional uranium reactors

Dispelling Claim 4: Thorium reactors are safer than  conventional uranium reactors  Thorium ‒ a better fuel for nuclear technology? Nuclear Monitor,   by Dr. Rainer Moormann  1 March 2018

The fission of U-233 results in roughly the same amounts

of the safety-relevant nuclides iodine-131, caesium-137

and strontium-90 as that of U-235. Also, the decay heat is

virtually the same. The differences in produced actinides (see

next claim) are of secondary importance for the risk during

operation or in an accident. In this perspective, thorium use

does not deliver any recognisable safety advantages.

Of greater safety relevance is the fact that uranium-233

fission produces 60% less so-called delayed neutrons than

U-235 fission. Delayed neutrons are not directly created

during the fission of uranium, but from some short-lived

decay products. Only due to the existence of delayed

neutrons, a nuclear reactor can be controlled, and the

bigger their share (for instance 0.6% with U-235), the

larger is the criticality range in which controllability is given

(this is called delayed criticality). Above this controllable

area (prompt criticality) a nuclear power excursion can

happen, like during the Chernobyl accident. The fact that

the delayed super-critical range is with U-233 considerably

smaller than with U-235, is from a safety point of view an

important technical disadvantage of thorium use.

During the design of thermal molten salt reactors (breeders),

the conclusion was that the use of thorium brings problems

with criticality safety that do not appear with classical

uranium use in this type of reactors. For that reason, it was

necessary to turn the attention to fast reactors for the use

of thorium in molten salt reactors. Although this conclusion

cannot be generalised, it shows that the use of thorium can

lead to increased safety problems.

As mentioned, a serious safety problem is the necessity to

restart breeder and reprocessing technology with thorium.

Thorium is often advertised in relation to the development

of so-called advanced reactors (Generation IV). The

safety advantages attributed to thorium in this context are

mostly, however, not germane to thorium (the fuel) but

rather due to the reactor concept. Whether or not these

advanced reactor concepts bring overall increased safety

falls outside the scope of this article, but that is certainly

not a question with a clear “yes” as the answer.

March 5, 2018 Posted by | 2 WORLD, Reference, safety, spinbuster, thorium | Leave a comment

Thorium reactors – NOT a solution to nuclear waste problem

Dispelling Claim 5: Thorium decreases the waste problem  

Thorium ‒ a better fuel for nuclear technology? Nuclear Monitor,   by Dr. Rainer Moormann  1 March 2018

Thorium use delivers virtually the same fission products

as classical uranium use. That is also true for those

isotopes that are important in issues around long-term

disposal.  Those mobile long-lived fission products

(I-129, Tc-99, etc.) determine the risk of a deep geological

disposal when water intrusion is the main triggering event

for accidents. Thorium therefore does not deliver an

improvement for final disposal.

Proponents of thorium argue that thorium use does not

produce minor actinides (MA)5, nor plutonium. They argue

that these nuclides are highly toxic (which is correct) and

they compare only the pure toxicity by intake into the body

for thorium and uranium use, without taking into account

that these actinides are hardly mobile in final disposal

even in accidents.

March 5, 2018 Posted by | 2 WORLD, Reference, spinbuster, thorium, wastes | Leave a comment

Climate change urgency: the Arctic is heating

Antarctic ice sheet loss and sea level rise Guardian, [Excellent graphs]  1 March 2018 

dana1981 more https://www.theguardian.com/environment/climate-consensus-97-per-cent/2018/mar/01/decisions-today-will-decide-antarctic-ice-sheet-loss-and-sea-level-rise

A new study looks at how much global sea level will continue to rise even if we manage to meet the Paris climate target of staying below 2°C hotter than pre-industrial temperatures. The issue is that sea levels keep rising for several hundred years after we stabilize temperatures, largely due to the continued melting of ice sheets in Antarctica and Greenland from the heat already in the climate system.

The study considered two scenarios. In the first, human carbon pollution peaks somewhere between 2020 and 2035 and falls quickly thereafter, reaching zero between 2035 and 2055 and staying there. Global temperatures in the first scenario peak at and remain steady below 2°C. In the second scenario, we capture and sequester carbon to reach net negative emissions (more captured than emitted) between 2040 and 2060, resulting in falling global temperatures in the second half of the century.

The authors found that global average sea level will most likely rise by about 1.3 meters by 2300 in the first scenario, and by 1 meter in the second. However, there is large uncertaintydue to how little we understand about the stability of the large ice sheets in Greenland and especially Antarctica. At the high end of possible ice sheet loss, we could see as much as 4.5 meters of sea level rise by 2300 in the first scenario, and close to 3 meters in the second scenario.

The study also shows that it’s critical that our carbon pollution peaks soon. Each 5-year delay – a peak in 2025 instead of 2020, for example – most likely adds 20 cm of sea level rise by 2300, and could potentially add a full meter due to the uncertainty associated with the large ice sheets:

we find that a delay of global peak emissions by 5 years in scenarios compatible with the Paris Agreement results in around 20 cm of additional median sea-level rise in 2300 … we estimate that each 5 years of delay bear the risk of an additional 1 m of sea-level rise by 2300 … Delayed near-term mitigation action in the next decades will leave a substantial legacy for long-term sea-level rise.

And remember, this is all for scenarios in which we meet the Paris climate targets, which we’re currently not on pace to achieve. If we miss the Paris targets, sea levels will rise higher yet.

Another new study, published in the Proceedings of the National Academy of Sciences, found that sea level rise has been accelerating. If the rate of acceleration continues – which the lead author notes is a conservative estimate – we would see an additional 65 cm (close to a meter above pre-industrial sea level) of sea level rise by 2100.

Yet another new study published in The Cryosphere using satellite data found that while the East Antarctic Ice Sheet has remained stable in recent years, ice loss from the West Antarctic Ice Sheet has accelerated. Antarctica is now discharging 1.93 trillion tons of ice each year, up from about 1.89 trillion tons per year in 2008. When accounting for snow accumulation, the continent is losing about 183 billion tons of ice per year – enough to raise sea levels by about 3 to 5 millimeters per decade by itself. The melting of the Greenland Ice Sheet is likewise accelerating and is now responsible for about 25% of annual sea level rise (8.5 millimeters per decade).

Meanwhile, the Arctic has been remarkably warm in February – as much as 35°C hotter than average in some areas. In mid-winter, when sea ice should be growing, in the Bering Sea it’s instead shrinking.

The hot Arctic is important because the temperature difference between the Arctic and lower latitudes is one of the main forces that keeps the jet stream moving steadily west-to-east. With a hot Arctic, the jet stream is weakened, leading to weird weather in the USA and Europe. As a result, the western states have been experiencing relatively quite cold temperatures, while the US east coast has been unseasonably hot.

To sum up, ice sheet melt is accelerating, as in turn is sea level rise. Even if we manage to achieve the Paris target of less than 2°C global warming above pre-industrial temperatures, we’re likely to eventually see more than a meter of sea level rise, and potentially several meters. The longer we take to reach peak carbon pollution in the coming years, the higher the oceans will rise. Disappearing sea ice in the rapidly-warming Arctic also appears to be causing increasingly weird and extreme weather in places like America and Europe.

March 3, 2018 Posted by | ARCTIC, climate change, Reference | Leave a comment

The Thorium lobby – religious fervour in attacking critics of the nuclear industry

Thorium Church: a trojan horse in the “green” movements. Here the Removal Tool.   “How do I know if my preferred “green” organization, or group, or leader… is infected by the ‘thorium church’ trojan horse?”. How to protect yourself from malicious propaganda of Thorium Church or from related compromised group or organizations. nonukes Italy, By Massimo Greco (June 2015)

What are trojan horses?

Trojan horses, otherwise known as trojans, are programs or applications that are inadvertently opened by the user, who expects the file to be something else..  by the same way “thorium supporters” are infecting forums, mailing list, debacts and environmental organizations.

It’s a strategy that is working in progress from some year. In few years they infected large part of the web. 

Like any malware, thorium’s priests are insinuated through any open space or open port .. and they are able to act at different levels. Mutating depending on the circumstances, improvising them selves as technicians or economists with the sole purpose of creating deviationism which in practice consists of annoying redirect to their cause that is regularly touted as a “green” solution or, even, “pacifist” or as a miraculous solution for the “salvation of the climate”.

Their function is aggressive, especially when you try to contradict them. Continue reading →

March 2, 2018 Posted by | 2 WORLD, Reference, secrets,lies and civil liberties, spinbuster, thorium | 1 Comment

Scan your environmental group for “thorium troll” infection

 nonukes Italy, By Massimo Greco (June 2015) “How do I know if my preferred “green” organization, or group, or leader… is infected by the ‘thorium church’ trojan horse?”

“……..Scanning and Removal, First check if the leader or “group leader” you are referring knows the problem of thorium, whether it has never taken a position on it. If the answer is “I do not know the problem” or “what you’re talking about,” you have the first certainty that your organization or target group is NOT protected.

If the answer is: “It is not a problem that concerns us”, “there is no matter in our topic or with antinuclear matter or uranium …”, or even worse … “nuclear thorium could be a clean way but the NWO prevents “… then you have the most certain that your group or environmental organization is terribly infected and that the leader is highly compromised.

If you are doing this survey “in public”, in a forum related to your organization reference, and after posting these sacrosanct questions and you are reproached or assaulted without causing or leading an intervention by the “admin” able to defend you, that’s another proof that your organization, or environmental group, results hugely infected.

You can also do a very easy search to see if the “admin” or the “most active” subjects are related to pro-thorium forums or registered as supporters of fan in groups offering thorium as a “savior” or “green”, especially when you attend to spam and suspicious behavior in the forums or social networks. You can do the same search about chemtrails or “HAARP” deviationism. As better Explained before, Thorium Church used very much the conspiracy decoy in order to mislead, confused and make it weak, vulnerable and unpractical environmental movements.

How to protect yourself from malicious propaganda of Thorium Church or from related compromised group or organizations.

If, as explained above, your reference group or environmental organization is infected: leave the group. This way you will avoid being accomplices. Thou hast tried, you have already taken the necessary steps. You’re not responsible. You have tried to change things.

If you are a “leader” or admin of a forum, or group… or green or environmental organization, you have to eject such people before they get completely the control of any topic. You have the duty to eject these individuals, without any hesitation of “democracy” and “freedom of confusion”… Because they, in the spaces controlled by the Thorium Church, do not allow you ever to contradict them and erase systematically, as their typical practice, anything that might cast doubt on their truth or propaganda. And, in any case, as admin or “leader” you have a duty to treat these subjects like any nuclearist that want to provoke discussion on the space that you are owning, or controlling.

If you are owning a youtube channel or any social page on social networks and you want to get protection from the thorium worm.. specially concerning antinuclear or environmental documents:

Simply “turn off” the option about “free comments” and choice comments under authorization or moderate. If you are admin of social pages delete their worms (spamming) and eject the vehicle of infection (for the reasons better explained before).

“How can I become active against cultural damages of pro-nuclear business propaganda of the Thorium Church?”

Ofcourse there are many different ways. Remember that pro-nuclear lobbies are pushing for the “new generation of nuclear power”, that means not only tradicional way of uranium. In fact they are talking about “nuclear of future”. So, “green”, environmentalist organizations, antinuclear people need to look about future strategies of the lobbies and not only to the past or the temporary, local, contingencies.

In recent years many antinuclear resources and internationally famous have taken a position on thorium. Just think about documents released by Bellona, Beyond Nuclear or to the Excellent article from Bob Alvarez on why thorium is not the wonder fuel it’s being promoted as and a brief history of the US’s persistent failure in making thorium safe or efficient ending with the expected trail of dangerous, weaponizable, waste… or the position of Helen Caldicott, violently attacked by the priests of the Thorium Church with a lot of insults like at the time of the “Scarlet Letter”…

[Dr. Arjun Makhijani on the downsides of the proposed thorium reactors (by Dr. Helen Caldicott)]

So it’s important to diffuse all the events, documents and positions, everywhere is possible, in order to counteract the mala information and debunking thorium commercials spot on the net.

To start an international and active support of the antinuclear movement in Indonesia, Malaysia, specially concerning the mobilization around Lynas, Koodankulam and any Rare Earth opposition in the West Asia. Promoting an active “UPGRADE” of all the antinuclear organizations.

Not only. You can help also supporting all the RNA spaces. Like this. For a new “NoThorium” activism. RNA was the first organization that started activism against thorium in Italy and in Paris. And at this moment has and diffuses the most rich archive of documents against thorium.

Better active today than radioactive tomorrow http://www.nonukes.it/rna/news326.html

March 2, 2018 Posted by | Reference, secrets,lies and civil liberties, spinbuster, thorium | Leave a comment

Vain hopes for Small Modular Nuclear Reactors (SMRs) – expensive and there are no customers anyway

Small Modular Reactors for Nuclear Power: Hope or Mirage? https://www.theenergycollective.com/m-v-ramana/2426847/small-modular-reactors-nuclear-power-hope-mirage   by M.V. Ramana 

Supporters of nuclear power hope that small nuclear reactors, unlike large  plants, will be able to compete economically with other sources of electricity. But according to M.V. Ramana, a Professor at the University of British Columbia, this is likely to be a vain hope. In fact, according to Ramana, in the absence of a mass market, they may be even more expensive than large plants.

In October 2017, just after Puerto Rico was battered by Hurricane Maria, US Secretary of Energy Rick Perry asked the audience at a conference on clean energy
in Washington, D.C.: “Wouldn’t it make abundant good sense if we had small modular reactors that literally you could put in the back of a C-17, transport to an area like Puerto Rico, push it out the back end, crank it up and plug it in? … It could serve hundreds of thousands”.

As exemplified by Secretary Perry’s remarks, small modular reactors (SMRs) have been suggested as a way to supply electricity for communities that inhabit islands or in other remote locations.

In the past decade, wind and solar energy have become significantly cheaper than nuclear power

More generally, many nuclear advocates have suggested that SMRs can deal with all the problems confronting nuclear power, including unfavorable economics, risk of severe accidents, disposing of radioactive waste and the linkage with weapons proliferation. Of these, the key problem responsible for the present status of nuclear energy has been its inability to compete economically with other sources of electricity. As a result, the share of global electricity generated by nuclear power has dropped from 17.5% in 1996 to 10.5% in 2016 and is expected to continue falling.

Still expensive

The inability of nuclear power to compete economically results from two related problems. The first problem is that building a nuclear reactor requires high levels of capital, well beyond the financial capacity of a typical electricity utility, or a small country. This is less difficult for state- owned entities in large countries like China and India, but it does limit how much nuclear power even they can install.

The second problem is that, largely because of high construction costs, nuclear energy is expensive. Electricity from fossil fuels, such as coal and natural gas, has been cheaper historically ‒ especially when costs of natural gas have been low, and no price is imposed on carbon. But, in the past decade, wind and solar energy, which do not emit carbon dioxide either, have become significantly cheaper than nuclear power. As a result, installed renewables have grown tremendously, in drastic contrast to nuclear energy.

How are SMRs supposed to change this picture? As
the name suggests, SMRs produce smaller amounts of electricity compared to currently common nuclear power reactors. A smaller reactor is expected to cost less to
build. This allows, in principle, smaller private utilities and countries with smaller GDPs to invest in nuclear power. While this may help deal with the first problem, it actually worsens the second problem because small reactors lose out on economies of scale. Larger reactors are cheaper
on a per megawatt basis because their material and work requirements do not scale linearly with generation capacity.

“The problem I have with SMRs is not the technology, it’s not the deployment ‒ it’s that there’s no customers”

SMR proponents argue that they can make up for the lost economies of scale by savings through mass manufacture in factories and resultant learning. But, to achieve such savings, these reactors have to be manufactured by the thousands, even under very optimistic assumptions about rates of learning. Rates of learning in nuclear power plant manufacturing have been extremely low; indeed, in both the United States and France, the two countries with the highest number of nuclear plants, costs rose with construction experience.

Ahead of the market

For high learning rates to be achieved, there must 
be a standardized reactor built in large quantities. Currently dozens of SMR designs are at various stages of development; it is very unlikely that one, or even a few designs, will be chosen by different countries and private entities, discarding the vast majority of designs that are currently being invested in. All of these unlikely occurrences must materialize if small reactors are to become competitive with large nuclear power plants, which are themselves not competitive.

There is a further hurdle to be overcome before these large numbers of SMRs can be built. For a company to invest
in a factory to manufacture reactors, it would have to be confident that there is a market for them. This has not been the case and hence no company has invested large sums of its own money to commercialize SMRs.

An example is the Westinghouse Electric Company, which worked on two SMR designs, and tried to get funding from the US Department of Energy (DOE). When it failed in that effort, Westinghouse stopped working on SMRs and decided to focus its efforts on marketing the AP1000 reactor and the decommissioning business. Explaining this decision, Danny Roderick, then president and CEO of Westinghouse, announced: “The problem I have with SMRs is not the technology, it’s not the deployment ‒ it’s that there’s no customers. … The worst thing to do is get ahead of the market”.

Delayed commercialization

Given this state of affairs, it should not be surprising that
 no SMR has been commercialized. Timelines have been routinely set back. In 2001, for example, a DOE report on prevalent SMR designs concluded that “the most technically mature small modular reactor (SMR) designs and concepts have the potential to be economical and could be made available for deployment before the end of the decade provided that certain technical and licensing issues are addressed”. Nothing of that sort happened; there is no SMR design available for deployment in the United States so far.

There are simply not enough remote communities, with adequate purchasing capacity, to be able to make it financially viable to manufacture SMRs by the thousands

Similar delays have been experienced in other countries too. In Russia, the first SMR that is expected to be deployed is the KLT-40S, which is based on the design of reactors used in the small fleet of nuclear-powered icebreakers that Russia has operated for decades. This programme, too, has been delayed by more than a decade and the estimated costs have ballooned.

South Korea even licensed an SMR for construction in
2012 but no utility has been interested in constructing one, most likely because of the realization that the reactor is too expensive on a per-unit generating-capacity basis. Even the World Nuclear Association stated: “KAERI planned to build a 90 MWe demonstration plant to operate from 2017, but this is not practical or economic in South Korea” (my emphasis).

Likewise, China is building one twin-reactor high- temperature demonstration SMR and some SMR feasibility studies are underway, but plans for 18 additional SMRs have been “dropped” according to the World Nuclear Association, in part because the estimated cost of generating electricity is significantly higher than the generation cost at standard-sized light-water reactors.

No real market demand

On the demand side, many developing countries claim to be interested in SMRs but few seem to be willing to invest in the construction of one. Although many agreements and memoranda of understanding have been signed, there are still no plans for actual construction. Good examples are the cases of Jordan, Ghana and Indonesia, all of which have been touted as promising markets for SMRs, but none of which are buying one.

Neither nuclear reactor companies, 
nor any governments that back nuclear power, are willing to spend the hundreds of millions, if not a few billions, of dollars to set up SMRs just so that these small and remote communities will have nuclear electricity

Another potential market that is often proffered as a reason for developing SMRs is small and remote communities. There again, the problem is one of numbers. There are simply not enough remote communities, with adequate purchasing capacity, to be able to make it financially viable to manufacture SMRs by the thousands so as to make them competitive with large reactors, let alone other sources of power. Neither nuclear reactor companies, 
nor any governments that back nuclear power, are willing to spend the hundreds of millions, if not a few billions, of dollars to set up SMRs just so that these small and remote communities will have nuclear electricity.

Meanwhile, other sources of electricity supply, in particular combinations of renewables and storage technologies such as batteries, are fast becoming cheaper. It is likely that they will become cheap enough to produce reliable and affordable electricity, even for these remote and small communities ‒ never mind larger, grid- connected areas ‒ well before SMRs are deployable, let alone economically competitive.

Editor’s note:

Prof. M. V. Ramana is Simons Chair in Disarmament, Global and Human Security at the Liu Institute for Global Issues, as part of the School of Public Policy and Global Affairs at the University of British Columbia, Vancouver.  This article was first published in National University of Singapore Energy Studies Institute Bulletin, Vol.10, Issue 6, Dec. 2017, and is republished here with permission.

February 22, 2018 Posted by | 2 WORLD, business and costs, Reference, Small Modular Nuclear Reactors | Leave a comment

WHAT ARE SALTED BOMBS?

Daily Mail UK, 17 Feb 18   A ‘salted bomb’ is a type of nuclear weapon that has been branded ‘highly immoral’ by some experts. The device aims to spread deadly radioactive fallout as far as possible rather than maximise explosive force.

The result is lasting environmental damage and vast areas of land left uninhabitable for decades.
Salted bombs take their name from the phrase ‘to salt the earth’, meaning to render soil unable to host life.

They are able to contaminate a much larger area than a traditional ‘dirty’ atomic bomb, like those used on Hiroshima and Nagasaki in 1945.To increase the radioactive destruction of salted bombs, certain radioactive isotopes are added to the device.

Heavy metals like gold, cobalt or tantalum can be used. Incorporating these metals into an atomic bomb would send high-energy neutrons at the stable element and turn it into a highly radioactive version. The radioactive isotope would then contaminate huge swathes of land.

A salted bomb is believed to be of lesser energy than other bombs due to these changes but could cause more long-term damage.

The idea of a salted bomb was first proposed by Hungarian-American physicist Leo Szilard during the Cold War.

Along with Albert Einstein, the scientist was instrumental in the beginning of the Manhattan Project.

No intentionally salted bomb has ever been atmospherically tested but the UK tested a 1 kiloton bomb incorporating a small amount of cobalt as an experimental radiochemical tracer in 1957. http://www.dailymail.co.uk/sciencetech/article-5400191/China-building-highly-immoral-salted-nuclear-bomb.html

February 17, 2018 Posted by | 2 WORLD, Reference, weapons and war | Leave a comment

Some of the problems with thorium nuclear reactors

Disadvantages of thorium reactors:  High start-up costs: Huge investments are needed for thorium nuclear power reactor, as it requires significant amount of testing, analysis and licensing work. Also, there is uncertainty over returns on the investments in these reactors. For utilities, this factor can weigh on the decisions to go ahead with plans to deploy the reactors. The reactors also involve high fuel fabrication and reprocessing costs.

High melting point of thorium oxide: As melting point of thorium oxide is much higher compared to that of uranium oxide, high temperatures are needed to make high density ThO2 and ThO2–based mixed oxide fuels. The fuel in nuclear fission reactors is usually based on the metal oxide.

Emission of gamma rays: Presence of Uranium-232 in irradiated thorium or thorium based fuels in large amounts is one of the major disadvantages of thorium nuclear power reactors. It can result in significant emissions of gamma rays.  http://nuclear.energy-business-review.com/news/major-pros-and-cons-of-thorium-nuclear-power-reactor-6058445

February 17, 2018 Posted by | 2 WORLD, Reference, thorium | Leave a comment

Research into low dose radiation – a very complex issue

A better direction for low-dose radiation research, BAS, Jan Beyea 12 Feb 18, 

With bipartisan support, the US House Science, Space, and Technology Committee recently passed a bill to revitalize low-dose radiation research. The bill, which would authorize an estimated $96 million in funding, has also garnered support from researchers and groups with opposing views on the seriousness of effects of ionizing radiation in the low-dose region, defined as being below 100 millisieverts—roughly the amount of radiation from 10 CT scans.

Studies of excess cancers among survivors of the Hiroshima and Nagasaki bombings have estimated a 1 percent increase in long-term cancer risk for adults receiving a dose of 100 millisieverts (the risk is higher for children), with the risk below that level declining in proportion to the dose. However, stakeholders and researchers with different hypotheses continue to debate whether or not downward extrapolation by dose magnitude—the “linear no-threshold” model deemed most reasonable by a National Research Council committee of experts—is the best way to estimate risk. ……

The hope of many supporters of the proposed legislation, voiced by Rep. Roger Marshall, a Kansas Republican, is that it may assist “the development of nuclear energy opportunities,” in part by reducing the size of nuclear plant evacuation zones. The bill’s supporters presume that the finding of a threshold or hormesis region would demonstrate that the existing linear no-threshold model is an over-protection that, as Northwestern University radiation biologist Gayle E. Woloschak wrote in a letter of support for the bill, “may be wastefully expensive and deplete funds that could be used for other strategic goals for the nation.”

Past research by the Energy Department to upend the linear model has failed to fulfill that dream, finding health effects below 100 millisieverts from even protracted exposures.  There is so much existing epidemiological data from exposed workers, patients receiving medical diagnostics, and residents living around the Soviet nuclear complex—as well as the Japanese atomic bombing survivors—that new research, whatever it shows, will need to be interpreted in the light of all the evidence.

That will likely leave stakeholders and experts debating for a long time, and the public confused.

Inherent uncertainty. New radiation research is likely to carry uncertainties, which means government policy must be conservative in its choice of the best dose-response model to use. Why is it difficult to tease out risks at low doses? Individual risks from medical diagnostics and from the (fortunately) limited releases of radioactivity at Fukushima are generally low under the linear extrapolation model. They are small compared with background disease rates, challenging epidemiological methods. The difficulty of finding effects among background cancers is actually good news for exposed individuals. However, the social risk is sufficiently large to justify keeping doses as low as reasonably achievable and balancing risks against benefits.

My colleagues and I call radiological events “reverse lotteries”: The individual risk of drawing a cancer-causing “ticket” from an event such as the Fukushima meltdowns is small, but because so many people are part of the lottery, real people do get impacted when they draw losing tickets.

Prospective risks and retrospective risks are perceived differently. If I learned that my family and I had already been exposed to a 1-in-1,000 cancer risk, I would be angry, but I would realize that the odds were highly in our favor; none of us would likely be injured. However, if you asked me to relocate to contaminated land where my children would be exposed to a 1-in-1,000 chance of cancer, I would want to stay away unless there were major benefits associated with the move, or if I thought I couldn’t afford to do otherwise. Risk tradeoffs are personal, and families can be painfully split on the best decision, as happened at Fukushima……… https://thebulletin.org/better-direction-low-dose-radiation-research11500

February 14, 2018 Posted by | radiation, Reference, USA | Leave a comment

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