Sunday, August 29, 2010
Thursday, August 26, 2010
Monday, August 23, 2010
Sunday, August 22, 2010
Saturday, August 21, 2010
Following is excerpted from a 2007 ACRS letter, ML071490090. It refers to Baker-Just as an anachronism although it does not say Baker-Just. This is so very interesting because ACRS approved several power level uprates that were justified based on compliance with Baker-Just.
UNITED STATES NUCLEAR REGULATORY COMMISSION
ADVISORY COMMITTEE ON REACTOR SAFEGUARDS
WASHINGTON, DC 20555 - 0001
May 23, 2007
The Honorable Dale E. Klein
U.S. Nuclear Regulatory Commission
Washington, DC 20555-0001
SUBJECT: PROPOSED TECHNICAL BASIS FOR THE REVISION TO 10 CFR 50.46 LOCA EMBRITTLEMENT CRITERIA FOR FUEL CLADDING MATERIALS
Zirconium alloy cladding used in current power reactors is embrittled by hydrogen absorption during normal operation and by oxidation and absorption of oxygen during the temperature transient associated with a LOCA. The requirements of 10 CFR 50.46 (a) and (b) limit the amount of embrittlement that may occur as result of a design basis accident. They specify limits for the peak clad temperature, the global oxidation of cladding, and the local oxidation of cladding. There are several deficiencies with the current regulations. The correlation specified for the rates of steam reaction with the cladding is viewed by the technical community as an anachronism. Cladding oxidation resulting from normal operation also contributes to embrittlement during a LOCA and can be significant in high-burnup fuel. Currently, not all licensees account for oxidation during normal operation in LOCA analyses. Also, since current requirements refer only to Zircaloy and ZIRLO cladding, the use of modern cladding alloys with superior performance requires regulatory exemptions.
Furthermore, in addition to its convenience in licensing power level increases, Baker-Just is referenced by power reactor licensees in their justification for pilot testing of "modern" cladding alloys. For example San Onofre's application to run some pilot M-5 assemblies is justified by Baker-Just. The approval by NRC is dated December 2009, over 2.5 years following the ACRS description of Baker-Just as an anachronism. Thus, San Onofre Units 2 and 3 will run some pilot M-5 bundles. They cite data reported by Framatome Cogema Fuels (FCF) to establish that M-5 metal-water reaction characteristics are bounded by Baker-Just. Click on the slide below to enlarge and then use your return arrow to get back here.
Sunday, August 1, 2010
So, how did this fall through the cracks?
The Baker-Just equation was published by the AEC during 1962; long before NRC was established during January 1975. Although it has a very weak foundation, the Baker-Just equation has survived to this day because it is convenient for licensing of nuclear power plants. This equation was first applied to the licensing of nuclear power plants during the era of the AEC when “regulators” were very strongly encouraged to expedite the role of what was then called atomic energy. The AEC, under the direction of the Congressional Joint Committee on Atomic Energy, worked very closely with the industry’s lobbying group then called the Atomic Industrial Forum. The lobbying group for today’s nuclear power industry is named the Nuclear Energy Institute (NEI).
It is unlikely that the nuclear power industry has ever commissioned a study of the roots of the Baker-Just correlation. However, today’s nuclear power industry fiercely defends Baker- Just. This defense is well documented by the NEI in its very recent comment 16 opposing PRM-50-93, “The Baker-Just correlation, using the current range of parameter inputs, has been shown to be conservative and adequate to assess Appendix K ECCS performance. Data published since the Baker-Just correlation was developed has clearly demonstrated the conservatism of the correlation above 1800°F,” refer to ML101040678, Industry Comments on Petition for Rulemaking (PRM-50-93); Multi-Rod (Assembly) Severe Fuel Damage Experiments. Docket ID NRC-2009-0554, April 12, 2010.
The NRC also fiercely defends Baker-Just. In its analysis of PRM-50-76, “The Baker-Just correlation (Reference 4) using the current range of parameter inputs is conservative and adequate to assess Appendix K ECCS performance. Virtually every data set published since the Baker-Just correlation was developed has clearly demonstrated the conservatism of the correlation above 1800°F.” refer to Memo to Matthews/Black-Technical Safety Analysis of PRM-50-76, A Petition for Rulemaking to Amend Appendix K to 10 CFR Part 50 and Regulatory Guide 1.157 - ML041210109, April 29, 2004.
Contrary to the exceptionally firm consistency between the NEI and NRC
evaluations of Baker-Just, the pertinent data sets published since the Baker-Just correlation was developed have clearly demonstrated the non-conservatism of the Baker-Just correlation above 1800°F. The NRC has never admitted that investigations that involve heating of single specimens of zirconium alloys in steam do not yield applicable data for the temperature or range of temperatures at which thermal runaway is initiated. Certainly, the NRC evaluators who produced ML041210109, April 29, 2004, should have been aware of the many references that are cited in PRM-50-93.
And, the following Letter from NRC to your blogger, ML100950085, documents in detail how Baker-Just fell through the cracks. NRC did not even have the key references in its files until your blogger persisted in demanding the key references. Click on the following to enlarge and use your back arrow to return here.
- that your blogger pursued the roots of Baker-Just,
- that NRC did not believe that those roots constituted a significant part of its basis for denying PRM-50-76,
- that those roots were not available in NRC files when it evaluated PRM-50-76,
- that those roots were not transferred to NRC when it was created in 1974,
- that NRC finally acquired and placed those roots in ADAMS during April 2010,
- that NRC promptly informed your blogger when those roots became available in ADAMS.
It is interesting that NRC did not believe that those roots constituted a significant part of its basis for denying PRM-50-76 even though those roots were not then available in NRC files.
Furthermore: I'm adding the following on August 8, 2009.
When the NRC placed document BMI-1154 into ADAMS during April 2009 the document was incomplete. I recently found this out when I was seeking the references on page C-48. I contacted BMI at Pacific Northwest Laboratories (PNL) and I was told that there was no page C-48, "No, it does not have page C-48." So I copied and e-mailed the table of contents and I replied, "I wonder how that vital list of references vaporized." Next PNL told me on 8/4/2010, "Bob, Try this version. I found it on Energy Citations Database (www.osti.gov/energy/citations). It has C-48. Thanks. Cheryl Wiborg." I sent that information to the NRC and the complete copy was placed into ADAMS. NRC thanked me on 8/5/2010 as follows: "The NRC version in ADAMS has been updated (ML100570218). It may take a couple of days to copy to the NRC public server, but it has been fixed. Thanks for locating a complete copy of BMI-1154. John Boska, Indian Point Project Manager, NRR/DORL, U.S. Nuclear Regulatory Commission." And here is the latest in ADAMS, it has 125 pages, prior to the correction by Boska it had only 98 pages.
So, I'll now add item 7 to the prior bulleted list because the above paragraph reveals:
- that your blogger studied BMI-1154 and effected corrections, although he did not immediately find the omissions in the ADAMS copy.