IR 05000352/1992021
| ML20128B495 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 11/27/1992 |
| From: | Bettenhausen L NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | Danni Smith PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| References | |
| NUDOCS 9212040001 | |
| Download: ML20128B495 (2) | |
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N0' V 2 71992
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- Docket Nos. 50-352 50-353 hir. D. h Senior Vice President -
Nuclear -
Philadelphia Electric Company Nudear Group Headquarters
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Cormspondence C ntrol Desk P.' O. Box 195 Wayne, PA 19087-0195
Dear Mr. Smith:
SUBJECT: INSPECTION NOS. 50-352/92-21; 50-353/92-21 This refers to your letter dated October 16,1992, in response to our letter dated September 18, 1992.-
Thank you for your response on this matter. Following further review, we question your justification on this issue. You have not provided 2nformation to support that the revised
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procedure can be effectively implemen%d by the operators. Thi:: procedure no longer contains discreet; easily identifiable crivria for the operator to determine when thermal hydraulic instabilities exist. _The lack of clear, quantified criteria could lead to a subjective identificat%n of conditions that require a manual reactor scram to prevent a Minimum Critical u
Power Ratio (MCPR) safety limit viohtion. We are referring this information to our Headquarters office, and a meeting may be necessary.
1We will keep you informed on developments in this area. Your cooperation with us is
ap r :ihted.
Sincerely, C
hat l-r
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Lee H. Bettenhausen, Chief, Operations Branch -
Division of Reacter Safety
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OFFICIAL RECORD COPY G: LIM 9221R-L
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PDR ADOCK 050003521 G
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hir. D. cc:
R. Charles, Chairman, Nuclear Review Board D. ". Helwig, Vice President - Limerick Generating Station G. J. Beck, hianager - Licensing Section G. hfadsen, Regulatory Engineer - Limerick Generating Station Secretary, Nuclear Committee of the Board Public Document Room (PDR)
Local Public Document Room (LPDR)
Nuclear Safety information Center (NSIC)
K. Abraham, PAO (2) (w/ copy of letter did October 16, 1992)
NRC Resident inspector (w/ copy ot letter dtd October 16, 1992)
Commonwealth of Pennsylvania (w/ copy of letter dtd October 16, 1992)
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Region 1 Docket Room (with concurrences)
L. Bettenhausen, DRS E. Wenzinger, DRP C. Anderson, DRP R. Conte, DRS DRS/EB SALP Coordinator V. McCree, OEDO R Clark, NRR A. Burritt, DRS DRS Files (2)
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/kf7 4049/92 jjfp92 116 92 h/17 OFFICIAL RECORD COPY G:1.lh19221R I
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PIIIL'DELPillA ELECTRIC COMI%NY LIMERICK GENERATING STATION P. O. BOX 2300 SANNIOGA, PA 19464 2300 Oct ober 16, 1992 (215) 3271200, EXT, 3000 Docket Nos.
50-352 50-353 DAgR. Hf G
License Hos. NPF-39 gg NPP~85 vuemcs acnenema swxw U.S.
Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555 SUBJECT:
Limerick Generating Station, Units 1 and 2 Reply to a Notice of Deviation NRC Inspection Report Nos.
50-352/92-21 and 50-353/92-21 Attached is Philadelphia Electric Company's reply to a Notice of Deviation for Limerick Generating Station (LGS) Units 1 and 2, which was contained in thc NRC Inspection Report Nos. 50-352/92-21 and 50-353/92-21 dated September 18, 1992.
The Notice of Deviation identified an apparent deviation from commitments made in response to NRC Bulletin No. 88-07 Supplement 1,
" Power Cacillations in Boiling Water Reactors ( BWRs), " dated December 30, 1988, which dealt with core thermal hydraulic instabilities.
The attachment to this letter provides a restatement of the deviation followed by our response.
if you,have any questions or require additional information, please contact us.
Very truly yours,
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.L JLP:cah Attachment cc:
T.
T.
Martin, Administrator, Region I, USNRC T.
J. Kenny, USNRC Senior Resident Inspector, LGS c q (p p \\ W D W -
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Attachment
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Page 1 of 2
DocLet Nos. 50-352/92-21 50-353/92-21
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Reply to a Notice of-Deviation Restatement of the Deviation During an NRC examinat ion conducted f rom July 20. through July 29, 1992, a deviation from your written commitments made in response to NRC Bulletin No. 88-07, Supplement 1, was identified.
In accordance with the, " General Statement of Policy and Procedure for NRC Enforcement Actions," 10 CFR Part 2, Appendix C
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(1992), the' deviation is listed below:
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In response to NRC Bulletin No. 88-07, Supplement 1, licensee letter dated March 7, 1989, states that Philadelphia Electric Company committed that the General Electric interim stability.
recommendations were completed and implemented for Limerick Unit 1 and would be used for the operation of Unit 2.
The following conditions for evidence of thermal hydraulic instabilities were i
incorporated into the approved plant procedureu:
" Average power range monitor (APRM) peak to peak oscillations greater than 10% or periodic local power
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range monitor (LPRM) upscale or downscale alarms in addition to the guidance provided in SIL 380, Revision 1."
Contrary to the above, Procedures OT-104,
" Unexpected / Unexplained Reactivity Insertion," and OT-ll2,
" Recirculation Pump Trip,"
were revised on June 12, 1992, such that it substantially changed so APRM peak to peak oscillations greater than 10% or periodic LPRM upscale or downscale alarms are not now considered evidence of instability.
RESPONSE
Philadelphia Electric Company (PECo) has determined that no deviation from commitments made in response to NRC Bulletin No.
88-07 Supplement 1 exists.
The revision to plant operating procedures, including OT-104 and OT-ll2, on June 12, 1992, further reduced the threshold.for operator response to an oscillation event and enhanced the detection and avoidance guidance.
Our' response to Bulletin No..
88-07, Supplement 1 was based on General Electric interim
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stability corrective action recommendations.
As more information became available from investigations into core thermal hydraulic instability, we adopted the more conservative Boiling Water Reactor Owners Group (BWROG) recommendation contained in BWROG letter BWROG-92030 dated March 18, 1992, " Implementation Guidance
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-Attachment
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Page 2 eof:2 Docket Nos. 50-352/92-21.
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50-353/92-21 for Stability Interim Corrective' Actions."
Procedures OT-104-and OT-ll2 were revised to. incorporate the fcllowing BWROG-92030 recommended conditions for evidence'of thermal hydraulic instabilities:
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Any LPRM or APRM noise signal grows by two or more times-its initial noise level.
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The characteristic of the LPRM and APRM signals change from random to a regular periodic variation (with approximately 1 to 2 second oscillation period).
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Period meters display strong positive to negative swings (with approximately 1 to 2 second oscillation period).
As a result of the revision to procedures OT-104 and OT-112, operators are expected to initiate a scram well before APRM, peak e
to peek oscillations exceed 10% or LPRM upscale or downscale alarms are received.
Furthermore, the NRC staff has reviewed BWROG-92030, which is the basis for the current procedural guidance.
In a September 17,.
1992, Nuclear Reactor Regulation staff presentation to the Advisory Committee for Reactor Safeguards the staff discussed the imminent issuance of an Information Notice which will endorse BWROG-92030 precautions.
In summary, no deviation from' commitments made in response to NRC Bulletin No. 88-07, Supplement 1 exists because the commitments made are bounded ay the guidance in the current revisions to plant operating procedures, including OT-104 and OT-112. 'APRM peak to peak oscillaticns greater than 10% or periodic LPRM upscale or downscale alarms are still considered _ evidence of instability.
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