nuclear-news

TEPCO discovers after 5 years that it could have quickly declared Fukushima plant meltdown

Nearly five years later, Tokyo Electric Power Co. said Feb. 24 that it has discovered a guideline in its operational manual that would have allowed it to announce meltdowns in the nuclear disaster in only days instead of the two months it actually took.
TEPCO apologized for failing to be aware for such a long time of the guideline on how to declare meltdowns at its Fukushima No. 1 nuclear power plant, triggered by the Great East Japan Earthquake and tsunami on March 11, 2011.
While the utility announced that reactor cores had been damaged at the No. 1 and No. 3 reactors by March 14 and at the No. 2 reactor by March 15, it did not admit that meltdowns had occurred in the three reactors until May 2011.
Based on its “nuclear disaster countermeasures manual,” which was revised 11 months before the disaster, the utility could have instead declared meltdowns at the three reactors by those dates, it said.
“We sincerely apologize for failing to confirm the presence of the guideline in the manual for five years,” a TEPCO spokesperson said Feb. 24.
The company will conduct an internal investigation to determine why it failed to promptly determine and announce meltdowns based on the manual.
In the few days after the Fukushima crisis unfurled, core meltdowns at the No. 1 to No. 3 reactors dispersed a large amount of radioactive materials into the environment.
Video footage of TEPCO’s in-house teleconferences around the time show that company executives recognized the possibility of meltdowns at the reactors from the early stages of the crisis.
But the company maintained that the reactors suffered “core damage,” a condition in which nuclear fuel inside a reactor core is damaged, rather than a “meltdown” at news conferences and in its announcements. In May it officially acknowledged that meltdowns had occurred.
The utility has explained that the delay was caused by the lack of a basis to assess meltdowns in the wake of an accident.
Early on May 14, 2011, TEPCO confirmed that the No. 3 unit had suffered damage to 30 percent of its reactor core and 55 percent of the No. 1 reactor’s core was damaged, based on rising radiation levels inside reactor containment vessels. It also determined that 35 percent of the No. 2 reactor’s core was damaged on the evening of May 15.
The newly discovered guideline in the disaster countermeasures manual, which was revised in April 2010, stipulates that the company should declare a meltdown when damage to a reactor core exceeds 5 percent, TEPCO officials said.
Company officials failed to announce the meltdowns because they were unaware of the guideline in the manual, according to TEPCO.
The existence of such a standard was confirmed earlier this month during an in-house investigation into how the utility responded to the Fukushima nuclear crisis.
The investigation is being conducted at the request of Niigata Prefecture where TEPCO’s Kashiwazaki-Kariwa nuclear power plant, which the company aims to restart, is located.
In a statement on Feb. 24, Niigata Governor Hirohiko Izumida called on TEPCO to conduct a thorough internal investigation to uncover the “truth behind its concealment of meltdowns,” including determining who gave instructions.
http://ajw.asahi.com/article/0311disaster/fukushima/AJ201602250043

February 26, 2016 Posted by dunrenard | Fukushima 2016 | Fukushima Daiichi, Meltdowns | Leave a comment

Tepco admits it should have declared meltdowns at Fukushima plant much earlier

Nearly five years after the nation’s worst nuclear accident, Tokyo Electric Power Co. has admitted that its staff failed to follow damage assessment guidelines, according to which they should have reported the meltdowns almost immediately.
A Tepco spokesman on Wednesday said the company’s Disaster Management Manual requires a reactor to be declared “in meltdown” if 5 percent or more of its fuel rods are determined to be “damaged.”
Tepco knew the extent of the damage early on. As of March 14, 2011, it estimated that 55 percent of the fuel rod assemblies of the reactor No. 1 and 25 percent of those at reactor No. 3 were “damaged,” based on the levels of radiation detected, Tepco spokesperson Yukako Handa told The Japan Times by phone.
Yet, despite widespread public skepticism at that time, the company refused to use the word “meltdown” for a period of about two months.
This led to widespread public speculation about a cover-up and failure to admit the extent of the damage. The sudden removal of a nuclear regulator spokesman fueled this.
Handa said a meltdown would have been declared if the guidelines had been followed correctly. But she said Tepco reported its estimates of damage to the government immediately — as required by law — and its failure to describe the situation as one of meltdown did not break regulations.
“Executives in charge of public relations at the time of the accident were not aware of the assessment criteria written in the Disaster Management Manual,” Handa said.
“They believed there was no clear definition of a ‘meltdown,’ so they didn’t make any clear remarks about one,’ ” she said.
Handa said Tepco will investigate why it failed to follow the assessment manual.
Wednesday’s announcement by Tepco was the first confirmation that such a manual even exists. NHK broke the news earlier in the day.
Whether to admit a “meltdown” was taking place at the plant was a sensitive topic for both the central government and Tepco from the start.
On March 12, one day after the tsunami knocked out power and cooling facilities, Koichiro Nakamura, a senior official at the now-defunct Nuclear and Industry Safety Agency, told a news conference that a “meltdown of a reactor’s core” may be taking place at the Fukushima plant, given the radiation levels detected.
Nakamura was promptly removed from a PR position at the agency, sparking speculation of a government cover-up of something critical underway at the site.
http://www.japantimes.co.jp/news/2016/02/24/national/tepco-admits-initial-assessments-fukushima-meltdowns-wrong/#.Vs33_ebzN_n

February 24, 2016 Posted by dunrenard | Fukushima 2016 | Fukushima Daiichi, Meltdowns | Leave a comment

TEPCO’s understanding of ‘meltdown’ questioned

https://www.youtube.com/watch?v=u70rnFc11_8&list=PLXoGEAuG5VBczXomsGFaKijtuuCW2mvtA&index=5

A new finding is raising questions about the explanation first offered for what was happening inside damaged reactors at the Fukushima Daiichi nuclear plant in 2011.

Nuclear fuel in 3 reactor cores melted following the earthquake and tsunami that March.

But Tokyo Electric Power Company officials failed to describe these as meltdowns.

They said there were no grounds for reaching that conclusion.

But 2 months later the utility formally admitted all 3 had melted down.

NHK has learned that the firm’s own manual says a meltdown has occurred if at least 5 percent of a core has melted. Nuclear fuel is housed in the core.

The operator told NHK it discovered this definition in the course of responding to a request from a Niigata Prefectural Government panel investigating the accident.

An NHK reporter says this would suggest TEPCO did not understand the precise definition of a meltdown until nearly 5 years after the accident.

The utility says it will continue to investigate why it didn’t use the word meltdown soon after the crisis began.

http://www3.nhk.or.jp/nhkworld/en/news/20160224_27/

February 24, 2016 Posted by dunrenard | Fukushima 2016 | Fukushima Daiichi, Meltdowns | Leave a comment