ML18311A297
| ML18311A297 | |
| Person / Time | |
|---|---|
| Site: | 99902037 |
| Issue date: | 11/30/2018 |
| From: | Ho Nieh Office of Nuclear Reactor Regulation |
| To: | Schrader K PWR Owners Group |
| Cusumano V, NRR/DSS, 4154011 | |
| References | |
| GL-2004-02 | |
| Download: ML18311A297 (2) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 November 30, 2018 Mr. Kenneth Schrader, PWR Owners Group Chairman PWR Owners Group, Program Management Office Westinghouse Electric Company, LLC 1000 Westinghouse Drive, Suite 380 Cranberry Township, PA 16066
SUBJECT:
STAFF RE-EVALUATION OF CLOSURE PATH FOR GENERIC SAFETY ISSUE 191 AND GENERIC LETTER 2004-02
Dear Mr. Schrader:
The U.S. Nuclear Regulatory Commission (NRC) staff is re-evaluating the closure path for Generic Safety Issue 191, Assessment of Debris Accumulation on PWR [Pressurized-Water Reactor] Sump Performance, and Generic Letter 2004-02, Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-Water Reactors
[PWRs], dated September 13, 2004 (Agencywide Documents Access and Management System Accession No. ML042360586), particularly as related to downstream in-vessel concerns. This generic letter resulted in the evaluation of potential adverse effects of post-accident debris blockage and operation with debris-laden fluids that may impair the recirculation functions of the emergency core cooling system (ECCS) and containment spray system.
This reevaluation recognizes that over the last 14 years, PWR licensees have made significant improvements to address these issues. All licensees installed larger ECCS sump strainers and many replaced problematic insulation materials with types that less adversely affect strainer performance. All plants also implemented programmatic changes to reduce the amount of debris that may be generated and transported to the sumps. Moreover, industry and the NRC staff have performed and reviewed a substantial amount of experimental and analytical work to increase the understanding of the phenomena associated with debris and potential adverse effects on both sump performance and downstream in-vessel effects.
If you have further technical questions regarding this matter, please contact, Mr. Victor Cusumano at 301-415-4011.
Sincerely
/RA/
Ho K. Nieh, Director Office of Nuclear Reactor Regulation Docket No. 99902037
ML18311A297 *Email Concurrence NRR-106 OFFICE NRR/DLP/PLPB/PM NRR/DLP/PLPB/LA* NRR/DLP/PLPB/BC NRR/TA* NRR/DSS/STSB*
NAME JDrake DHarrison DMorey JJohnston VCusumano DATE 11/19/2018 11/20/18 11/23/2018 11/7/2018 11/7/2018 OFFICE NRR/DORL* NRR/DSS* NRR/DMLR* NRR NAME CErlanger MGavrilas GWilson HNieh DATE 11/28/2018 11/27/2018 11/27/2018 11/30/2018