ML20206F141
| ML20206F141 | |
| Person / Time | |
|---|---|
| Issue date: | 04/27/1999 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20206F139 | List: |
| References | |
| NUDOCS 9905060003 | |
| Download: ML20206F141 (3) | |
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U.S. NUCLEAR REGULATORY COMMISSION QEFICE OF NUCLEAR REACTOR REGULATION SAFETY EVALUATION OF 4
- BWRVIP VESSEL AND INTERNALS PROJECT. BWR STANDBY LIQUID CONTROL SYSTEM / CORE PLATE AP INSPECTION AND FLAW EVALUATION GUIDELINES (BWRVIP-27t" EPRI REPORT TR 107286. APRIL 1997
1.0 INTRODUCTION
1.1.
Background
By letter dated April 25,1997., the Bolling Water Reactor Vessel and Intemals Project (BWRVIP) submitted the Electric Power Research institute (EPRI) proprietary report TR-107286, "BWR Vessel and lnternals Project, BWR Standby Liquid Control System / Core Plate AP Inspection And Flaw Evaluation Guidelines (BWRVIP 27)," April 1997. This report was supplemented by a letter dated July 13,1998, which was in response to the staff's request for additional information (RAl), dated December 14,1997.
The BWRVIP-27 report provides generic guidelinas intended to present the appropriate inspection recommendations to assure safety function integrity of the subject safety related <
reactor pressure vessel (RPV) intemal components. It also provides design information on the core plate AP/ Standby Liquid Control (AP/SLC) system, geometries, weld locations, and potential failure socations for the several categories of boiling water reactors (BWR/2 through BWR/6).
1.2 Purpose The staff reviewed the BWRVIP-27 report to determine whether its guidance will provide-acceptable levels of quality forinspection and flaw evaluation of the subject safety-related l
RPV internal components. The review considered the consequences of component failures, potential degradation mechanisms and past service experience, and the ability of the proposed inspections to detect degradation in a timely marner.
1.3 Organization of this Report Because the BWRVIP report is proprietary, this SE was written so as not to repeat information contained in the report. The staff does not discuss in any detail the provisions of the guidelines nor the parts of the guidelines it finds acceptable. A brief summary of the contents of the BWRVIP-27 report is given in Section 2 of this SE, with the evaluation presented in Section 3. The conclusions are summarized in Section 4. The presentation of the evaluation is structured according to the organization of the BWRVIP-27 'eport.
ENCLOSURE 9905060003 990427 PDR TOPRP EXIEPRI C
. 2.0
SUMMARY
OF BWRVIP-27 REPORT The BWRVIP-27 report addresses the following topics:
Comoonent Descriotiort and Function - The various core plate AP/SLC system configurations are described in detail by a series of illustrations along with brief descriptions of each configuration's function and characteristics. Differences among the various models of BWRs (BWR/2, BWR/3-5 and BWR/6) are identified.
Susceeut,ility Factors -The various types of material degradat!on mechanisms (fatigue, e
stress corrosion cracking, age embrittlement) that could impact the AP/SLC intemals are characterized. Materials, stress, and environmental factors are described in general terms, and followed by specific referenc6s to actual occurrences for each degradation mechanism relative to plant operating experience for particular mechanisms and components.
Potential Failure Locations and Safety Conseauences - Each of the vessel penetration e
configurations are addressed from the standpoint of inspection history, future susceptibility to degradation, and consequences of failures in terms of component functions and plant safety. Based in these qualitative considerations, the BWRVIP 27 report makes recommendations as to the need for inspections for each of the AP/SLC system configurations, Boron Mixina and Leakaae Considerations - The mixing and leakage issues related to a
the degradation of AP/SLC intemals are qualitatively and quantitatively addressed in this section, Backaround and Insoection History-Data on service related failures of components o
are summarized. The major sources of such data are the various GE SILs and Rapid i
information Communication Service Information Letters (RICSILs),
BWRVIP insoection Guidelines - The guidelines recommend the specific locations, e
NDE methods, and inspection frequencies for examinations of core plate AP/SLC intemals. The BWRVIP 27 report recommends that for most configurations, the current ASME inspection requirements be followed. For some configurations, however, an additional ultrasonic (UT) examination is recommended.
' 3.0 STAFF EVALUATION The NRC staff has completed its review of BWRVIP-27 and the BWRVIP's response July 13, 1998. The NRC staff has determined that the contents and recommendations in the BWRVIP-
'27 report, when coupled with the BWRVIP's responses to the specific information requests in the staff's RAI of December 14,1997, provides a sufficient and acceptable basis for performing examinations of the AP/SLC intemals and for evaluating postulated flaw indications
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in the SLC systems; The flRC staff therefore concludes that the recommendations in BWRVIP-27 are acceptable and may be applied at BWR facilities.
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4.0 CONCLUSION
The staff has reviewed the BWRVIP-27 report and finds that the guidance of the BWRVIP-27 report is acceptable for inspection and flaw evaluation of the subject safety-related RPV intemal components. The staff has concluded that licensee implementation of the guidelines in the BWRVIP-27 report wiil provide an acceptable level of quality forinspection and flaw evaluation of the safety-related components addressed.
5.0 REFERENCES
1.
Carl Terry, BWRVIP, to USNRC, "BWR Vessel and Internals Project, BWR Standby Liquid Control System / Core Plate AP inspection And Flaw Evaluation Guidelines (BWRVIP 27)," EPRI Report TR-107286, dated April 1997.
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