ML042290626

Industry Progress on Effect of Chemical Reactions on PWR Sump Performance

ML042290626
Person / Time
Issue date:	08/25/2004
From:	Sheron B NRC/NRR/ADPT
To:	Pietrangelo A Nuclear Energy Institute
Solorio, D L, NRR, 415-0149
References
Download: ML042290626 (3)

Text

August 25, 2004 Anthony R. Pietrangelo Senior Director, Risk Regulation Nuclear Generation Nuclear Energy Institute 1776 I Street, N.W., Suite 400 Washington, D.C. 20006-3708

SUBJECT:

INDUSTRY PROGRESS ON EFFECT OF CHEMICAL REACTIONS ON PWR SUMP PERFORMANCE

Dear Mr. Pietrangelo:

By letter dated May 28, 2004, the Nuclear Energy Institute (NEI) submitted the outstanding sections and appendices to NEI report on sump performance evaluation methodology. The methodology is intended to help the industry and the Nuclear Regulatory Commission (NRC) resolve generic safety issue (GSI) 191, Pressurized-Water Reactor (PWR) Sump Performance. As noted in the executive summary and Section 7.4 of the methodology, NEI does not provide any guidance on the assessment of chemical effects on PWR sump performance. In the NEI sump performance evaluation methodology, NEI states that:

Guidance to address the effects of corrosion products on head loss is deferred until the [planned] testing is completed and the data have been appropriately evaluated.

At several public meetings on the results from NRC-sponsored research and the development of NEI sump performance evaluation methodology, NRC management has identified the need for the industry to address the uncertainties associated with the effect of chemical reactions on PWR sump performance in a proactive manner. Since the ongoing test program to address these uncertainties may not be completed prior to the time that PWR licensees are expected to evaluate the performance of containment sumps and, if necessary, design solutions, NRC management has stated that it may be prudent to introduce a reasonable amount of margin in the NEI sump performance evaluation methodology to account for these uncertainties and to avoid the potential to have to make additional design changes to the sumps once the ongoing test program is complete.

In correspondence to the staff, dated, July 12, 2004, (ADAMS Accession Number ML042290564),

NEI stated support for this position and mentioned that NEI is currently looking into a process to facilitate the introduction of margin to address uncertainties associated with the effect of chemical reactions on PWR sump performance. We would appreciate it if you would keep the staff informed of your ongoing activities to introduce an appropriate amount of margin into the NEI sump performance evaluation methodology.

I appreciate your continued attention to this important matter. If you have any questions concerning this letter, please contact Mr. David Solorio at 301-415-0149.

Sincerely,

//RA//

Brian W. Sheron Associate Director for Project Licensing and Technical Analysis Office of Nuclear Reactor Regulation

ML042290626 OFFICE SPLB:DSSA SPLB:DSSA SPLB:DSSA NRR:DE NRR:DSSA NRR/ADPT NAME MGiles DSolorio JHannon LLund SBlack BSheron DATE 08/20/04 08/20/04 08/20/04 08/20/04 08/20/04 08/25/04