ML17202U803
| ML17202U803 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 08/23/1990 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML17202U800 | List: |
| References | |
| GL-88-01, NUDOCS 9008290213 | |
| Download: ML17202U803 (3) | |
Text
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IJNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 ENCLOSURE 4 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 3 DOCKET NO. 50-249
- 1. 0 INTRODUCTION Connnonwealth Edison Company, the licensee, submitted its respoi:ise to NRC
.Generic*Letter {GL) 88-01, *NRC Position on IGSCC in BWR Austenitic Stainless Steel Piping"* for Dresden Nuclear Power Station, Unit 3, by letter dated July 29, 1988, and additiona 1 information as requested by the staff was provide(.by let.ter dated,Ju.ly 21, 1989.
GL 88-01 requested licensees and construction permit holders to resolve ttie.Jntergranular Stress Corro_sion Cracking {IGSCC) issue for BWR.piping made of a~stenjtic stainless steel*
that is four, inches or larger in nominal dJameter and contains reactor coolant at a temperature above 200 degrees_Fahrenheit during power operation regardless *of tode classification. Jhe license~ was requested to address the following:*
- 1.
.2.
- 3.
- 4.
- 5.
1he current pJans regarding pipe replacement and/or other measures taken
. -to mi ti gate IGSCC and provide assurance of continued -long-term integrity and reliability.
T~e Inservi~e Inspection {ISi) Program to be implemented at the next refueling outage for austenitic stainless steel piping covered under the scope of this letter that conforms to the staff positions on inspection schedules, ~ethods and personnel, and sample expansion included in
.*. GL 88-01.
The Technical Specification {TS) change to include a statement in the section
- on ISi that the ISi Program for piping covered by the scope of this lett~r will be-in staff positjpns on schedule, methods and persoQnel, and sample expansion included in GL 88~01 {see model BWR Standard Technical Specifications enclosed in GL 88-01).
It* is recognized that the Inservtce 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.
The confirmation of your plans to ensure that the TS related to leakage detection will be in conformance with the staff positions on leak*detection included in GL 88-01~
The plans to notify the-NRC.Jn:_ac_co_rdanc~ 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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- 2 Code for continued operation without evaluation, or a change found iri the condition of the welds previously known to be cracked and your evaluation of 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 Reports (TERs) are VSI's evaluation of the licensee's response to NRC.GL 88-01.
The staff has reviewed the TERs and
- concurs with the evaluations, conclusions, and recommendat-ions contained in.
_the TER with the exception as.discussed be.low with regards to licensee's
- positions IGSCC classifications of castings.* In the review of the licensee'.s GL 88-01 submittal, the staff has found the following positions to be*.
unacceptable:
- 1.
The licensee's position which excludes welds fo piping fo the portions
- of the Reactor Water Clean-up (RWCU) outboar~ of "the isolatioJJ.valves.
- 2.
The licensee's: position not to amend the*Ts t~ include a statemen~ ~n ISI as required in GL 88-01.
I
- 3.
- The licensee's position to average the unidentified leak.rate over~-
24-hour period.
For a detailed discuss*ion of these items,* see Sections 2.0 and 3.0 of the TER.
The above identified.ite~s, with regards to TS ~men~ments, have been approved by the Committee to Review_ Generic.Requirements-as part of GL 88-01 with
- the exception that unidentified 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 -hours as required in GL 88-01. Jh.e staff has re-evaluated the frequency of leakage monitoring. After discussions with several 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 ta.ken 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.
- 3.0 _CONCLUSION Bas~d on.the.review of the licensee's NRC GL 88-01 response~ the siaff.
concludes that the response, as evaluated, is acceptable w-ith the exception of the licensee's positions as identified above.
The licensee is requested
.to submit a TS change that would require an ISI statement and leakage
- 3 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.
Furthermore, the licensee must submit inspection plans for the RWCU piping outboard of the isolation valves *
. The staff also concludes that the proposed IGSCC inspection and mitigation program will provide. reasonable assurance of maintaining the long-term structural integrity of auste'nitic stainless steel pip~ng in the Dresden
- =.
- Nuclear Power Station, Unit 3.
Pfincipal°Contributors:* W. Koo T. Mclellan Dated: Augu~t 23, 1990 *
',*