Entergy Nuclear on the defensive re: Palisades pressurized thermal shock risks
Figure by Hiromitsu Ino, CNIC-TokyoAs reprinted at Yahoo Finance, Entergy Nuclear's site vice president at its Palisades atomic reactor in Covert, MI, has issued a statement standing by the integrity and safety of his badly embrittled reactor pressure vessel (RPV), vulnerable to a catastrophic fracture due to pressurized thermal shock (PTS). Such a fracture would lead to a Loss of Coolant Accident (LOCA) in the reactor core, and probable meltdown.
Anthony Vitale stated in a prepared statement:
"This is not a new topic or one that is unique to Palisades. In fact, for decades pressurized thermal shock has been well understood and well monitored by the owners and operators of the nation's pressurized water reactors."
What Vitale's statement failed to mention is that Palisades has the single worst embrittled reactor pressure vessel in the U.S. Environmental watchdogs forced NRC officials to admit this at a public meeting near Palisades on Feb. 29, 2012. NRC officials again acknowledged this fact on the March 19, 2013 Webinar (see entry below).
Vitale's claims of PTS risks being "well understood and well monitored" are also highly dubious. After NRC officials admitted that the last metal coupons, or capsules, extracted from Palisades' reactor pressure vessel had been analyzed in the mid-1990s and 2000s, Beyond Nuclear's Kevin Kamps asked the following question:
"If capsules were removed in the mid-1990s and 2000s, as NRC just said, that's a decade or two ago. Has NRC simply extrapolated to predict the severity of embrittlement? What if NRC's understanding is flawed? What if the extrapolation is non-conservative? How can NRC speak with any confidence, if the last physical data collected -- and very few data points at that -- are over a decade old? This is not science. This is guesswork. The safety risks are too high for this lack of science."
NRC did not answer the question -- but one of many questions Kevin and others asked that went unanswered.
An article by the Citizens Nuclear Information Center (CNIC)-Tokyo's Hiromitsu Ino calls into question Vitale's claims that PTS risks are "well understood." Ino's July 2011 paper, "Aging Nuclear Power Plants focusing in particular on irradiation embrittlement of pressure vessels," was published in two parts (see Part I here; see Part II here). The paper was also summarized CNIC-Tokyo's newsletter (Part I in the May/June 2012 edition; Part II in the July/August edition). Mr. Ino's figures and tables can be viewed here.
Ino included this alarming warning: the Japanese nuclear industry's understanding of reactor pressure vessel embrittlement and pressurized thermal shock risks are significantly non-conservative. This can be seen in the graph above. The Japanese nuclear industry and its governmental regulators thought they "well understood" embrittlement, but when they finally "monitored" Genkai-1, they found embrittlement worse than they had ever predicted.
Palisades has but two metal capsules left. Vitale said they would extract one this autumn for examination. Watchdogs are calling for genuinely independent, third party technical experts to review, verify, and authenticate all aspects of this test, due to deep distrust of not only Entergy, but also NRC.
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NRC is also on the defensive regarding Palisades' reactor pressure vessel (RPV) embrittlement and pressurized thermal shock (PTS) risks. On March 18th, NRC issued its own clarification "***FOR THE RECORD***", entitled "PRESSURIZED THERMAL SHOCK AND PALISADES" (all caps and emphasis in original). This was one day before NRC conducted a Webinar on the subject, well attended by concerned local residents and environmental group watchdogs.
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NRC Region 3 Administrator, William Casto, confirmed at the grassroots meeting with NRC Commissioner Magwood on March 25th (see website entry just above) that the March 19th webinar on embrittlement at Palisades was attended by 119 people, who asked 85 questions. Casto committed to those questions being answered in writing.