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Hurricane Ida Shuts Down One Nuclear Plant in Louisiana.

Hurricane Ida Shuts Down One Nuclear Plant in Louisiana. Simply Info , August 29, 2021

Hurricane Ida prepares to make landfall mid day in Louisiana. The storm is predicted to be the strongest hurricane to hit the state in history as a strong cat 4. Hurricane Katrina had dropped to a category 3 by the time it made landfall yet caused extreme damage. Sustained winds reported this morning were 150 mph.

Entergy shut down Waterford nuclear plant around 10am Sunday due to the expected wind speeds. Ed Lyman at the Union of Concerned Scientists documented the flood risk at the plant when combining the predicted storm surge and rainfall. The plant may not flood in the reactor block area but it could end up surrounded by water. Entergy, the company that operates the plant mentioned they have sequestered enough staff on site to conduct needed operations and restart the plant whenever that might be possible. In Ed Lyman’s twitter posts about this issue he also cited dry cooling towers used at the site and that they require sump pumps to keep them operational. Depending on the water inundation that system could be offline until water recedes………….

August 30, 2021 Posted by | climate change, incidents, USA | Leave a comment

Nuclear Regulatory Commission finds cable issues in special inspection of Vogtle Unit 3

Nuclear Regulatory Commission finds cable issues in special inspection of Vogtle Unit 3,  Augusta Chronicle Abraham Kenmore, 27 Aug 21, The federal Nuclear Regulatory Commission has finished its special inspection of the Plant Vogtle Unit 3 expansion. The report found several preliminary issues with how cables had been installed during the construction of the new nuclear power facility.

“The NRC inspectors found that Southern Nuclear did not adequately separate safety and non-safety-related cables for reactor coolant pumps and equipment designed to safely shut down the reactor,” according to a press release sent with the report. “They also found instances where the company did not identify and report construction quality issues related to the safety-related electrical raceway system and enter them into its corrective action program.”

Southern Nuclear, the company in charge of construction, can choose to accept the results of the inspection or provide additional information before a final determination is reached. Unit 3 currently has no fuel loaded into the reactor and the press release makes it clear there is no increased risk to the public from the safety issues. Southern Company will not be allowed to operate the reactor until construction is finished to standards………

August 30, 2021 Posted by | safety, USA | Leave a comment

Greater powers to be given to UK’s armed Civil Nuclear Constabulary – a threat to peaceful protest?

UK Government plan to give armed nuclear police more powers raises ‘profound concerns The Ferret,Billy Briggs
August 23, 2021

A UK Government plan to give an armed police force called the Civil Nuclear Constabulary (CNC) greater powers has raised “profound concerns” and been described as “deeply worrying”.

The CNC is a specialist force tasked with protecting civil nuclear sites in Scotland, England and Wales and nuclear materials in transit both in the UK and internationally. 

Counter-terrorism is a major part of its policing and the force employs 1,500 police officers. The CNC guards nuclear sites at Torness, Hunterston and Dounreay in Scotland, among other places across the UK.

It’s remit is set out in the Energy Act 2004 but the UK Government has just held a consultation seeking views on a plan to expand and diversify the force’s role.

Anti-nuclear groups have voiced fears over the proposal, however, arguing that the CNC’s remit should be limited to civil nuclear sites. The Scottish Greens said that centralised control over an armed police force with new powers would be a “very concerning development”…………..

Those responding to the consultation included the UK and Ireland Nuclear Free Local Authorities (NFLA) which submitted a joint response with anti-nuclear groups – Blackwater Against New Nuclear Group, Together Against Sizewell C, CADNO, People Against Wylfa B, Stop Hinkley and Nuclear Waste Advisory Associates.

The NFLA argued that the CNC’s powers should be “limited to civil nuclear sites, as its title implies”. Any expansion to other roles and duties for the CNC, they argued, would “represent an expansion of nuclear police at expense of the civil police force”

Councillor David Blackburn
, NFLA steering committee chair, said: “NFLA has joined with these six other campaigning groups to raise its profound concerns that an expansion of the Civil Nuclear Constabulary and an increase in its powers is moving it in the wrong direction. What is required rather is concerted efforts to reduce the risks of the UK’s nuclear legacy and to avoid developing new nuclear reactor sites.”

He argued that by making nuclear sites safer “there will become less of a need for an armed police force”.

“The concerning wider push for new laws which could reduce peaceful protest also greatly concerns us,” Blackburn said. “The proposals in this consultation move the CNC further into being an extensively armed police force, when we should instead be looking at ways to have a democratically controlled and accountable police force protecting the public in a measured way.”………

August 24, 2021 Posted by | civil liberties, safety, UK | 1 Comment

Los Alamos nuclear laboratory warns it might shoot down drones

Los Alamos Labs Threatens To Shoot Down Your Drone

Lab Warns Against Hobbyist Drone Flights  
Updated August 23rd, 2021

LOS ALAMOS, N.M. (AP) — Drone pilots beware. Authorities at one of the nation’s top nuclear weapons laboratories issued a warning Monday that airspace over Los Alamos National Laboratory is off limits.

The birthplace of the atomic bomb, Los Alamos lab reported that recent unauthorized drone flights have been detected in restricted airspace in the area. Officials said if you fly a drone over the lab, you likely will lose it.

We can detect and track a UAS (unmanned aircraft system), and if it poses a threat, we have the ability to disrupt control of the system, seize or exercise control, confiscate or use reasonable force to disable, damage or destroy the UAS,” said Unica Viramontes, senior director of lab security.

The lab would not release any specifics about how the system works, citing security protocols. They also would not say how many unauthorized flights have occurred in recent months.

Lab officials also warned of the potential for “collateral interceptions” of normal commercial or hobbyist drone flights, saying pilots should stay well outside the lab’s restricted airspace and the additional no-drone zone designated by the Federal Aviation Administration.
According to the FAA, drones are prohibited from flying over sites designated as national security sensitive facilities. Aside from military bases and other Department of Defense sites, restrictions are in place for national landmarks and certain critical infrastructure such as nuclear power plants.

August 24, 2021 Posted by | safety, USA | Leave a comment

Danger if sirens are turned off: Point Beach Nuclear Reactor courts disaster

Point Beach Reactor Courts Disaster with Sirens Turned Off,  CounterPunch BY JOHN LAFORGE 16 Aug 21,

A change to “emergency response” has been made at the 50-year-old Point Beach nuclear reactors on Lake Michigan south of Green Bay, Wisconsin. The operators, NextEra Energy Point Beach (NextEra), have turned off the site’s disaster warning sirens.

That’s right, no more wailing sirens to warn of potentially catastrophic radiation releases or spills from the two old reactors. The two reactors, both Westinghouse units, are respectively 51 and 49 years old, well past their designed maximum of 40 years………………

Emergency preparedness and disaster response have always been the bane of nuclear reactors — the only industrial systems that are required to have evacuation plans. Some sites such as Seabrook in New Hampshire are incapable of a mass evacuation and should never have licensed to operate. Taking down warning siren systems only increases the likelihood of catastrophe. It amounts to reckless endangerment.

August 24, 2021 Posted by | safety, USA | Leave a comment

Point Beach Nuclear Unit 1 Emergency Shut-Down

Point Beach Nuclear Unit 1 Emergency Shut-Down

AUGUST 11, 2021 BY 8 O’CLOCK BUZZ   On July 31, 2021, the Point Beach Nuclear Power Reactor experienced a number of valve and computer monitoring failures which could have been catastrophic, had it not been for manual overrides performed. Hannah Mortenson, Executive Director of Physicians for Social Responsibility WI, talks about the poorly publicized incident involving the 50-year-old complex (which was designed for a 40 year service period), and their request to the NRC to send an inspection team to the reactor site.

August 24, 2021 Posted by | safety, USA | Leave a comment

5.2-magnitude quake strikes off Japan’s Fukushima Prefecture, no tsunami warning issued 

5.2-magnitude quake strikes off Japan’s Fukushima Prefecture, no tsunami warning issued Xinhua| 2021-08-22 TOKYO, Aug. 22 (Xinhua) — An earthquake with a magnitude of 5.2 struck off Japan’s Fukushima Prefecture on Sunday, according to the Japan Meteorological Agency (JMA).

The temblor occurred at around 11:24 a.m. local time, with its epicenter at a latitude of 37.6 degrees north and a longitude of 141.7 degrees east, and at depth of 60 km.

The quake logged 4 in some parts of Fukushima Prefecture on the Japanese seismic intensity scale which peaks at 7.

So far no tsunami warning has been issued.

August 23, 2021 Posted by | Japan, safety | Leave a comment

Canada’s nuclear reactors may not be fit for service

Canada’s nuclear reactors may not be fit for service,  Rabble ca,  Joyce Nelson, 11 Aug 21,  On July 13, Bruce Power announced that two reactors at its Bruce Nuclear Generating Station in Kincardine, Ontario had violated its operating license.

It had “higher than anticipated readings” of hydrogen-equivalent concentration (Heq) in pressure tubes in two units. Pressure tubes must not exceed the allowable limit of 120 parts per million of Heq. Each pressure tube in a reactor contains 12 bundles of uranium, which are the basis for the nuclear reaction, but the pressure tubes also contain the coolant that keeps the fuel from overheating and triggering a meltdown. Pressure tubes with high levels of Heq can develop cracks and fractures, thereby compromising a reactor’s safety.

As The Globe and Mail reported:

“In response to Bruce Power’s contraventions, on July 13, the CNSC [Canadian Nuclear Safety Commission] ordered the company, along with fellow CANDU [Canada Deuterium Uranium] operators Ontario Power Generation (OPG) and New Brunswick Power, to review the fitness for service of their pressure tubes and report back no later than the end of July.”

Aging reactors

Many of Canada’s aging CANDU reactors are older than their design-life for pressure tubes, which originally was designated as 210,000 effective full power hours (EFPH), or about 30 years.

When Hydro Quebec’s Gentilly-2 CANDU reactor reached that limit, it closed the plant.

As The Globe and Mail reported:

“Thierry Vandal, chief executive at the time, testified before Quebec’s national assembly that he considered 210,000 EFPH ‘the extreme limit’ beyond which his management team dared not go. ‘I would no more operate Gentilly-2 beyond 210,000 hours than I would climb onto an airplane that does not have its permits and that does not meet the standards,’ he said, according to a translated transcript.”

Under industry pressure, the Canadian Nuclear Safety Commission subsequently raised the limit to 247,000 EFPH in 2014, and then to 295,000 EFPH in 2018.
In 2018, the CNSC extended OPG’s license for its Pickering Nuclear Generating Station for 10 years. Rather than require that OPG replace aging pressure tubes, the regulator mandated more frequent inspections.
When asked how often pressure tubes are checked, retired nuclear scientist and radioactive chemistry expert Dr. Frank Greening answered by email:

“Pressure tubes are checked for their hydrogen/deuterium concentrations about every two years, but it’s a little more complex than that. Each CANDU unit contains about 400 tubes and each tube is about six meters in length. This means it’s next to impossible to check every tube at every location, so only about 10 tubes are checked at a time. In addition, corrosion and [hydrogen/deuterium] pickup are expected to be most significant at the hot, outlet end of each tube, so samples are usually restricted to this location.”

As a result of such limited inspections, the industry relies on mathematical models to predict how long the untested tubes can safely remain in service. But this modeling is not necessarily accurate, as evidenced by the July 13 “higher than anticipated readings” at Kincardine.

Indeed, in March 2021, The Globe reported:

“Documents obtained under the federal Access to Information Act by Ottawa researcher Ken Rubin, and provided to The Globe, show that since 2017, CNSC staffers had grown increasingly concerned about unreliable data arising from OPG’s inspections of pressure tubes…The whole method by which operators assessed fitness for service of pressure tubes had been called into question.”

Another Fukushima?………………….

August 21, 2021 Posted by | Canada, safety | Leave a comment

Limited consultation on UK’s commercial nuclear ships’ safety regulations.

On 9 August 2021 the UK Maritime and Coastguard Agency (Agency) published a Consultation (Consultation) on the draft merchant shipping (nuclear ships) regulations 2021 (Regulations). The Consultation seeks views from interested parties (Consultees) on the proposed Regulations which will transpose the International Convention for the Safety of Life at Sea, 1974 (SOLAS Convention) into UK law.

The proposed Regulations only cover commercial ships with nuclear propulsion systems and do not cover barge-mounted reactors for power generation or floating nuclear plants. Responses to the Consultation will be accepted until the 5th of October 2021.

 JDSupra 13th Aug 2021

August 16, 2021 Posted by | safety, UK | Leave a comment

Inconclusive findings on attempted sabotage of Belgian nuclear reactor.

The seven-year-long investigation into an attempted sabotage of the Doel
nuclear power plant in 2014 has ended inconclusively.

The incident took place on 5 August 2014, when the reactor at the Doel 4 installation shut
down automatically. Inspections revealed a disturbance in the steam turbine
in a non-nuclear part of the complex. It soon became clear that the problem
was an act of sabotage: someone had manually opened a valve in the plant
evacuation system, intended to quickly evacuate the 65,000 litres of oil
used to lubricate the turbine to an emergency reservoir in the case of

No order had been given to open the valve, and operators Electrabel
filed a criminal complaint for sabotage with the prosecutor’s office in
Dendermonde in East Flanders. But when the possibility of a terrorist
motive was raised, the investigation moved to the federal prosecutor’s
office, where all terrorist cases are handled.

One of the first discoveries made by investigators was the dubious status of the plant’s own security
measures. There were no CCTV cameras in strategic places – like the
vicinity of the blue valve that set off the alarm – to check who had
opened it.

 Brussels Times 13th Aug 2021

August 16, 2021 Posted by | EUROPE, safety | Leave a comment

Turkey’s Akkuyu nuclear station a cause for anxiety in the Eastern Mediterranean

Turkey’s Akkuyu nuclear power plant is a cause of concern  August 15, 2021  Dr Yiorghos Leventis

Turkey is an energy hungry economy. According to the International Atomic Energy Agency (IAEA) assessment of Turkey’s energy needs in 2020, the country currently imports approximately 72 per cent of its energy demand.

To address the problem of increasing domestic energy demand, Ankara has been actively pursuing nuclear energy to lessen its high dependency on energy imports. Consequently, in May 2010, Russia and Turkey signed a cooperation agreement, under which Rosatom State Cooperation has since been constructing the Akkuyu  nuclear power plant (NPP). This NPP will eventually contain four reactors with a combined capacity of 4800 MW. Other nuclear power projects in Sinop, Black Sea region and the Eastern Thrace region remain in the planning stages.

Construction of the Akkuyu NPP begun in December 2017. Its final cost is expected to rise to over 20 billion USD – roughly equivalent to the size of Cyprus’ economic output in 2020. The first reactor is expected to become operational in 2023, the year that marks the centenary anniversary of the Republic of Turkey. No doubt, Erdogan’s government is planning festivities for this significant event, to boost its plunging popularity.

Despite serious concerns about the safety of the Akkuyu NPP, located as it is, in the high seismic activity region of Mersin, construction continues. Every consecutive year in the following three years (2024-26) will see a new reactor coming into operation.

The first controversy over the impact of this huge nuclear power project on the environment appeared already six years ago: on January 12, 2015, it was reported that the signatures of specialists on a Turkish government-sanctioned environmental impact report had been forged. The appointed specialists had resigned six months prior to its submission, and the contracting company had then made unilateral changes to the report. Naturally so, this revelation sparked protest within the Turkish Cypriot community. The proximity of the prospective Akkuyu nuclear power plant to our island could not be lightheartedly ignored. This powerful NPP will operate at about 110 kms from Nicosia. In the context of an unexpected nuclear accident caused by an earthquake or otherwise, north or south Cyprus becomes immaterial. A fatal nuclear accident carries the danger of overwhelming both parts of the island.

In this respect, it is vital that the leaderships of both Greek and Turkish Cypriots stand in unison: the Eastern Mediterranean environment and its protection is a common cause. More so as Ankara exhibits a mixed approach, to say the least, towards international legal instruments on nuclear safety: Whereas Turkey signed up to the Convention on Nuclear Safety which entered into force October 24, 1996, it has not done the same with the Joint Convention on the Safety of Spent Fuel Management and on the Safety of Radioactive Waste Management which entered into force June 18, 2001.

Dr Yiorghos Leventis is director of the International Security Forum:

August 16, 2021 Posted by | safety, Turkey | Leave a comment

Widening concrete cracks in Seabrook Nuclear Station

Nuke Plant Cited Over Widening Concrete Cracks, The Town Common by Stewart Lytle, Thursday August 1
2, 2021  REGIONAL – The Nuclear Regulatory Commission (NRC) slapped the wrist of Seabrook Station Thursday for not projecting the likely deterioration of its structural concrete caused by alkali-silica reaction (ASR).

In a 20-page quarterly inspection report, the NRC issued a Green finding, its lowest level of citation, to NextEra. It found that the staff of the New Hampshire nuclear plant “did not adequately account for the future progression of ASR in their prompt operability determination for several Seabrook structures. 

“Specifically, NextEra staff did not trend and project the periodic threshold monitoring data for the affected structural elements to ensure the structures would remain capable of performing their safety functions to the next scheduled inspection.”

Starting last fall, the NRC conducts inspections at Seabrook Station every six months. 

During their walk-through of the plant, the inspectors also found that three structures – the emergency feedwater pumphouse, service water cooling tower and control and diesel generator building – had widening cracks that exceeded the design limits. The mechanical penetration area also has cracks that are approaching the limits. 

Once a threshold limit is exceeded, more frequent inspections are required and may result in corrective action such as a structural modification to alleviate the condition, the report stated.

The 30-year-old atomic reactor has concrete infected by ASR, an irreversible type of concrete degradation, caused by water reacting with the concrete. It has been called “concrete cancer.” 

The inspectors were also concerned with the degradation of the steel rebar in the concrete structures. …………….

relative to Seabrook’s ASR testing and monitoring program.  While the Board ultimately approved the plant’s concrete management program, it did so with four new license conditions that direct NextEra Seabrook to conduct much more frequent and stringent monitoring and engineering evaluations in a number of situations. They were:

  • NextEra must increase the frequency of monitoring from 10 years to six months.
  • NextEra must develop a monitoring program to anticipate or monitor rebar failures.
  • If the cracks in the concrete get worse, NextEra must monitor the concrete more often. 
  • Each concrete core extracted from Seabrook must undergo a detailed microscopic petrographic evaluation to detect microcracks. 

“It’s frightening to think that were it not for C-10’s challenge, the inspection interval referenced in this report may have been as long as a decade,” Treat said. “Now NextEra has to perform them every six months. But collecting data without using it to model future trends in concrete degradation is of little use.”

August 16, 2021 Posted by | safety, USA | Leave a comment

Russian nuclear submarine lost propulsion in Danish waters, sails submerged outside Norway now

Russian nuclear submarine lost propulsion in Danish waters, sails submerged outside Norway now Danish Navy describes the situation as “dramatic” when the giant Oscar-II class submarine “Orel” drifted at 1,5 knots towards the island of Sejerø. Ropes were prepared for towing and two other Russian warships came to assist.  Barents Observer,  By Thomas Nilsen August 04, 2021  Orel” was sailing together with the navy tug “Altay” and the large anti-submarine missile destroyer “Vice-Admiral Kulakov” in an inter-fleet transit from St. Petersburg towards the Kola Peninsula when it got problems with propulsion and started to drift.

The incident happened on July 30 in the busy waters east of Denmark’s second-largest city Århus. “Orel” and the two other Northern Fleet vessels had a few hours earlier sailed under the Great Belt Bridge en route out of the Baltic Sea towards Skagerak.

Orel” was sailing together with the navy tug “Altay” and the large anti-submarine missile destroyer “Vice-Admiral Kulakov” in an inter-fleet transit from St. Petersburg towards the Kola Peninsula when it got problems with propulsion and started to drift.

The incident happened on July 30 in the busy waters east of Denmark’s second-largest city Århus. “Orel” and the two other Northern Fleet vessels had a few hours earlier sailed under the Great Belt Bridge en route out of the Baltic Sea towards Skagerak.

“The escort out of the Baltic Sea will go down in history as both dramatic and exciting, as the nuclear-powered submarine “Orel” of the Oscar-II class had problems with propulsion and lay dead in the water at Sejerø, where it drifted with 1,5 knots towards the island,” the crew on the Danish patrol vessel writes.

They elaborate by explaining how they could see a crowd of crew members came out on the front deck of “Orel”, all wearing life jackets.

The Northern Fleet navy tug “Altay” came closer and ropes were prepared for towing the large submarine. “MDMS Diana” offered help, but such assistance was “politely but nor surprisingly refused,” the Danish navy writes.

Radio communication did not take place directly with the submarine, but was answered by the crew on the Russian destroyer “Vice-Admiral Kulakov”.

After a while, the Russian submarine managed to get going again and all the rigged gear for towing was taken down.

“From Diana, we closely followed the situation on the submarine and our thought quickly turned to the film The Hunt for the Red October when we saw all the people on the deck of the submarine,” the crew on the Danish patrol vessel said and added: “VERY exciting to witness up close.”

No official comments 

The Russian navy has not posted any information about why the submarine lost proposition or if the incident was linked to the operation of the nuclear reactors or any other parts of the auxiliary systems.

The press service of the Northern Fleet is not allowed to speak directly to foreign media, including the Barents Observer.

Norwegian military worried 

As the nuclear submarine’s propulsion was restored in time to avoid a larger accident, the Russian navy ships continued north into Skagerak, the waters between Denmark and Norway’s southern tip. 

At first, the submarine sailed in surface position, but it has now submerged underwater, Norway’s Joint Headquarters tells the Barents Observer.

The Norwegians are closely following the voyages with the Russian warships now sailing north outside the coast towards the Northern Fleet’s home bases at the Kola Peninsula.

“It is always worrying when a vessel of this type has problems with propulsion,” says spokesperson Major Elisabeth Eikeland with the Joint Headquarters.

She says it is normal that Russian submarines during such inter-fleet transits are followed by their own support and auxiliary vessels.

“But we also expect Russian authorities to contact us if they again have problems with this or other vessels in waters near Norway,” Major Eikeland underlines.

Additional to the nuclear-powered submarine “Orel” several other Northern Fleet warships are currently sailing north after participating in the Main Naval Parade outside St. Petersburg on July 25.

Currently outside Norway are the two nuclear-powered submarines “Vepr” and “Knyaz Vladimir”. While “Vepr” is an Akula-class multi-purpose sub, the “Knyaz Vladimir” is the Northern Fleet’s newest ballistic missile sub of the Borei-class…………………..

August 7, 2021 Posted by | Denmark, incidents | Leave a comment

British Navy secrecy over nuclear submarine crashes

– The Royal Navy has refused to say whether anyone was disciplined following
an incident in which a nuclear submarine nearly crashed into a ferry
carrying 282 people off the Scottish coast. The navy also won’t say
whether it carried out an independent review to reduce the risks of future
collisions. This was recommended by government investigators concerned
about the near-miss and two other nuclear submarine crashes. Campaigners
accuse the navy of using the excuse of national security “to cover up
dangerous incompetence”. The Scottish National Party (SNP) condemns the
secrecy as “absolutely untenable”.

 The Ferret 5th Aug 2021

August 7, 2021 Posted by | incidents, secrets,lies and civil liberties, UK | Leave a comment

Framatome’s sub-standard nuclear fuel is threatening the survival of France’s nuclear company EDF

 It is not only in China, in the world’s first operational EPR nuclearreactor, that the fuel produced by EDF’s subsidiary, Framatome, is a problem. In France, in the Ardennes, an unprecedented incident on the nuclear fleet has just occurred in a reactor and potentially concerns ten reactors, to varying degrees of severity.

This nuclear fuel that poisons the life of EDF

by Martin Leers,  Le Journal de l’energie 2nd Aug 2021

Metal guards that enclose the reactor fuel, called cladding, deteriorate too quickly. A problem far from trivial: fuel cladding plays a key role in the safety of nuclear reactors. This “accelerated” corrosion appeared between 2020 and 2021 in one of the two reactors at the Chooz power plant. A fault which currently forces EDF to extend its shutdown since March 2021 and has therefore already cost it more than a hundred million euros.

But the stakes for EDF are much more important than a shutdown of a reactor. The “M5” alloy sheaths, which wear out prematurely in Chooz reactor n ° 2, are fitted to all EPR reactors in France, Finland and China, as well as dozens of other reactors in France and abroad.

Is there a link between this incident in France and that of the leaking ducts of the first EPR reactor in service in the world in Taishan (China)?

Why do these latest generation sheaths wear out prematurely?

A burning question for EDF, which is trying to convince the Nuclear Safety Authority (ASN) and the Institute for Radiation Protection and Nuclear Safety (IRSN) to reuse cladding with questionable reliability in reactors.

How did the problem come to be at the Chooz nuclear power plant?

When the Chooz reactor n ° 2 was shut down in February 2021 to reload the fuel, particles were discovered on the fuel assemblies and in the water of the primary circuit [1] . “Numerous white migrant bodies of a few millimeters were either collected by the anti-debris devices or remained on the assemblies”, explained EDF in an internal letter to ASN, dated July 7, 2021. An abnormal phenomenon . These particles are zirconium oxide which originates from the surface of the fuel cladding. [2] Their presence indicates that the sheaths are degrading. “The consequence of an abnormally high corrosion rate”, clarified EDF in the letter to ASN.

These particles are very friable and cannot cause a loss of tightness in the nuclear fuel, explained Karine Herviou, deputy director general of IRSN, to the Journal de l’énergie .

The fuel claddings are tubes more than 4 meters long and less than 1 centimeter in diameter, very thin (0.6 mm thick) in which the uranium pellets are stacked. These sheaths, commonly called rods, are brought together in assemblies, each made up of 264 sheaths. The core of Chooz nuclear reactor No. 2 contains 205 assemblies. In Chooz reactor n ° 2, the abnormal wear is only in the upper part of certain assemblies.

What consequences for the safety of the nuclear reactor could have the accelerated wear of the fuel rods?

The cladding plays an important role for reactor safety: they form the first barrier between nuclear fuel, containing very dangerous radioactive substances, and the environment. They must prevent radioactivity from spreading in the water circulating in the nuclear core. However, “damage to the surface of certain fuel cladding calls into question the demonstration of the integrity of the fuel in service”, considers ASN. This means that this incident calls into question the parameters which guarantee, in the eyes of ASN, the safety of the reactor in normal operation and during accident scenarios.

“Accelerated corrosion is likely to weaken the cladding and increase the risk of loss of integrity of the rods concerned during accidental transients and therefore lead to rupture of the first barrier”, explains EDF in the internal letter to ASN from July 7, 2021. But EDF does not consider this scenario plausible.

What are the causes of abnormal wear of the fuel rods?

EDF estimated on July 7 that “at this stage of the investigations, no single cause appears at the origin of the phenomenon of accelerated corrosion (…) which rather finds its explanation in a combination of several unfavorable factors”. But the M5 alloy from which the sheaths are made “seems to be the trigger,” notes EDF.

The iron content of the sheaths singled out

It is the low iron content of the cladding alloy which is partly responsible for their degradation. Two production batches for low iron content sheaths have been identified by EDF. The most damaged sheaths come from these lots, which EDF calls “hyper sensitive castings”. But until the February 2021 incident on Chooz reactor no.2, slight variations in iron in the cladding alloy were not considered to be a factor in the degradation of the fuel rods. The variable iron content of fuel cladding does not appear to have been perceived as a problem in France by the fuel assembly manufacturer, Framatome, or by the operator EDF, or by ASN and IRSN.

The sheaths which deteriorate are “in conformity” with the specifications

“The iron content of these batches is within the standards”, explains IRSN. “The products supplied by Framatome comply” with the specifications, “iron was not considered as a characteristic parameter for the behavior of the rods in the core. », Adds ASN.

Following the incident, EDF informed ASN that the iron content will be increased in the cladding which will be used in reactor No. 2 at Chooz from “cycle 20”. Not the next time the reactor is reloaded, but the next.

A “multifactorial” phenomenon

The iron content of pencils is not the only culprit. EDF puts forward other causes to explain the degradation of the fuel cladding. The temperature is higher at the top of the nuclear core in the most powerful reactors, those of 1450 MW, than in the less powerful reactors, those of 1300 MW. It is in this area that the cladding deteriorated in two 1,450 MWe reactors in France. What would happen if low iron cladding was introduced into EPR reactors, even more powerful than the 1450 MW reactors?

Another unfavorable element: the positioning of the fuel assemblies in the reactor vessel. “The corrosion rate depends on the place of an assembly in the reactor core during the first cycle”, particularly in the four most powerful reactors in the French fleet, explains EDF in an internal document. [3]

An unprecedented incident in France but not abroad

If this wear had never been observed in France, it had already occurred on three nuclear reactors in Brazil and Germany, two of which used the same M5 alloy. [4] As at the Chooz power station, the most worn cladding was the one with the lowest iron content. “The phenomenon of accelerated corrosion observed at the end of cycle 18 of Chooz B2 is comparable to other events in Konvoi reactors abroad”, notes EDF in the internal letter to ASN. Therefore, why was this incident not anticipated in France when the nuclear operators and institutions say they maintain a permanent dialogue on safety at the global level?

The nuclear safety experts from the German GRS institute have not been able to fully identify the causes of the corrosion of the cladding on German reactors, adds Karine Herviou of IRSN.

M5 alloy sheaths are fitted to all EPR reactors in France, Finland and China, as well as dozens of other reactors.

Designed to be more corrosion resistant than previous alloys and to improve nuclear fuel efficiency, the M5, manufactured by Framatome, is widely used in nuclear power worldwide.

“A large majority of reactors in France use assemblies with M5 cladding,” explains Karine Herviou of IRSN. Framatome claims its M5 sheaths are used in 96 nuclear reactors around the world, in a 2018 brochure .

The same cladding is used in the EPR reactors at Flamanville (Manche), Olkiluoto in Finland and Taishan in China. M5 alloy sheaths had many leakage problems in the 2000s, says a 2008 IRSN report:

“Between 2001 and 2008, around thirty fuel assembly leaks with M5 alloy cladding were detected. To date, EDF has identified three types of faults causing leaks in fuel rods with M5 alloy cladding. »Defects now corrected……………

10 nuclear reactors in France affected by the cladding defect discovered at the Chooz power plant

For the moment, ten nuclear reactors in France are directly or indirectly affected by the defect in the cladding discovered on the reactor n ° 2 at Chooz.

“To date, seven 1,300 MWe reactors and three 1,450 MWe reactors have at least one rod with a low iron content, in the core or in the management reserve,” ASN told the Journal de l’énergie .

But the inventory of potentially defective rods is still in progress, “even if it should not change”, added ASN. In addition to the two production batches for low iron content sheaths, EDF identified other batches of concern and informed ASN of them in an internal letter. How many ? Mystery.

“An inventory of the iron content of each of the rods of each of the assemblies present in the reactor or in reserve is being drawn up”, specifies ASN…………..

Is EDF’s priority to save fuel even if it means playing stunts with nuclear safety?

EDF is therefore forced to adapt the operation of the two reactors to the defective ducts with “compensatory” measures. EDF proposes that Chooz reactor no. 2 only operate at 92% of its power during its next cycle. For Chooz reactor n ° 1, the operator proposes to reduce load monitoring. [6] “Depending on the elements, EDF could be required, on reactors 1 of Chooz, 1 and 2 of Civaux and 3 of Cattenom to take compensatory measures (either to limit maneuverability or to operate at a drop in power)” , announces the operator in the internal letter of July 7, 2021 to ASN.

Measures that would have a financial impact. The aim, explains ASN, is “not to allow a reactor operating mode where this corrosion acceleration is possible”.

IRSN must deliver its opinion on EDF’s proposals in a few weeks, then ASN will decide.

Why does EDF not give up using potentially defective cladding in reactors? Is it about saving fuel even if it means doing acrobatics with nuclear safety?

Neither EDF nor Framatome answered questions from the Journal de l’énergie .

August 5, 2021 Posted by | France, safety | Leave a comment