ML17202U801
| ML17202U801 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 08/23/1990 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML17202U800 | List: |
| References | |
| GL-88-01, GL-88-1, NUDOCS 9008290178 | |
| Download: ML17202U801 (3) | |
Text
. l UNITED STATES NUCLEAR ~EGULATORY COMMISSION WASHINGTON, D. C. 20555 ENCLOSURE 2
- SAFETY EVALUATION BY THE.OFFICE OF NUCLEAR REACTOR REGULATION REVIEW OF RESPONSE TO NRC GENERIC LETTER 88-01 COMMONWEALTH EDISON COMPANY DRESDEN *NUCLEAR POWER STATION, UNIT 2
'DOCKET NO. 50-237 L 0 INTRODUCTION Conunonwea 1th Edi son Company, the 1 i cens*ee, *submitted its response to NRC Generic*
- Letter (GL) 88-01, "NRC Positi9n on IGSCC in BWR Austenitic Stainles~ Steel Piping" for Dresden' Nucl~ar Power Station, Unit 2 by letter dated July 29, 1988,
- and add iti ona 1 information as. requested by the* staff was prov ide.d by letters dated October 5, 1988, December 21, 1988, and March 1, 1989:
GL 88-01 requested licensees and construction permit holders.to resolve the* Intergranul,ar Stress Corrosion Cracking (IGSCC) issue for* BWR. piP.ing made of austenitic stainless
-steel that is four inches* or larger.in* nominal diameter* and contains reactor coolant at a temperature above 200 degrees Fahrenheit during poweroperation'._
- regardless of Gode classification. The licensee was requested to address
. the_Jollow.ing:
- 1.
The.current plans regarding pipe replacement and/or other measures taken to mit'igate
- IGSCC and provide assurance of continued long.:term integrity *
- and re 1 iabil ity.
- 2.
The !~service Inspection (iSI) Program t6 be implemented at t~e next r~fueling outage for austenitic stainless steel piping covered under the scope of this letter that conformsto the staff positions on inspection schedules,* methods and personnel, and.sample expansion included in *.
- 3.. Th~ Technical Specification (TS) change to include a statement i~ the section on ISI that the ISI Program.for piping ~ov~red by the scope of this
- letter will be in staff p~sitions on schedule,. methods. and personnel, and
~ample expansion included in GL 88~01 (see model BWR Standard Technical
- Specification enclosed in GL 88-01}~ It is recognized**that the Inservice
- Inspection and Testing sections may be removed from the Technical Specifications Improvement programs.
In this case, this requirement
.shall remain with the ISI section when it is *included in an alternative
- document.
- 4.
The confirmation o*f your plans to ensure that the TS related to leakage detection will be ib conformance with.th~ staff positions on leak detection included in GL 88-01.
- 5.
The plans to notify the NRC in accordance with 10 CFR 50.55a(g) of any flaws identified that do not meet IWB-3500 criteria of Section XI of the
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. Code for continued operat~on without evaluation, or a change found in the conditii:>n of the welds previously known to be cracked and your evaluati.on
~f the flaws for continued operation and/or your repair plans.
2.0 DISCUSSION
- The licensee's response to NRC GL 88-01 has been reviewed by the staff with the assistance of its contractor, Viking Systems International (VSI).
The _
attached Technical Evaluation Report~ (TERs) are VSI's evaluation of the licensee's response to NRC GL 88-01.,The staff has reviewed the TER~ and concurs with the evaluatioris,. conclusions, and recommendations contained in
_the TER with the exception as discussed.below with regards to litensee's positions IGSCC classifications of castings. In the review of.the li~ensee's
- GL.88-01 submittal, the staff has found th~ foilowing positions to*be
- unacceptable:
- 1.
The.lice~see's positi6n on a 50% reduciiori*of the inspection schedule based on hydrogen water treat!'lent.
- 2.
The ljcensee's posjtion not to *amend the TS to include a statement on ISI as r.equired in GL 88-01.
3.-
-Th~ l.icensee's position to average the unidentified leak.rate over a*
. *24~ho~r period~
- 4. *.The licen~ee*'s position concerning *the operability requirements of the leakage monitoring *instrume~~s outlined in GL 88-01.
For a.detail~d discussion of these item~, see S~ctioris 2.0 and 3.0 ~f the TER *
.*The above identified item*s with. regards to TS amendments have been approved
- by the Committee to Review Generic Requirements as part of GL 88-01 with.
the exception tha.t unidentified l~akage may be monitored every 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />
- instead of every 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> as required i~ GL 88-01.
The staff has re.;.evaluated the. frequency of leakage* monitoring. 'After discuss ions with severa 1 BWR
- operators the staff concluded that monitoring every 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> creates an unnecessary administrative hardship to the plant operators. Thus, Reactor Coolant System (RCS) leakage measurements may be taken every 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> instead
- of every 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> as required. i_n GL 88-01.
The licensee needs to address the Reactoi ~ater Clean-up (RWCU) piping outboard of the isolation valves. If ~he piping-is within the scope of GL 88-01, the Jicens~e wi-11 need to list the.identify of the we,lds, and -plans.
- for mitigation and inspections or proviqe alterna_tive proposals.
- 3.0 CON CL US ION Based on the review of the licensee's NR~ Gl 88-01 response, the staff conclude~ that the response, as evaluated, is acceptable with th~ exception of the licensee's positions as identified above.
The licensee *is requested to submit a _TS change that wot.ild require an ISI statement and leakage
- requirements as required in GL 88-01 with the exception that leakage may be monitored every 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> instead of.every 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> as required in GL 88-01.
Since, the licensee's request to reduce the inspection schedule by 50% has been denied at this time, the licensee must submit future IGSCC inspection plans based o~ the requirements in GL 88-01.
The staff also concludes that the proposed IGSCC inspection and mHigation program will provide reasonable assurance of maintaining the _long-term structural integrity of austenitic stainless steel piping in.the Dresden Nuclear Power Station, Unit 2.
- Principal Contributors~ W. Koo T. McLel lan Dated:
August 23, 1990
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