ML20104A515
| ML20104A515 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 09/03/1992 |
| From: | Creel G BALTIMORE GAS & ELECTRIC CO. |
| To: | NRC OFFICE OF ENFORCEMENT (OE) |
| References | |
| NUDOCS 9209140018 | |
| Download: ML20104A515 (5) | |
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B A LTIMORE -
GAS AND ELECTRIC 1650 CALVERT CLIFFS F.'.RKWAY + LUSBY, MARYLAND 20657 4702 GEORGE C CREC.
scwon ves P4tsir.tv (4:0)260-3490 l
September 3,1992 U. S. Nuclear Regulatory Cornmission Washington, DC 20555 i
j ATTENTION:
Director, Office of Enforcement SUBIECT:
Calvert Cli(Ts Nuclear Power Plant Unit Nos.1 & 2; Docket Nos. 50-317 & 50-318 i
Nonce of Violation - Electrical Distribution System Functional Inspection (EDSFQLimppetion Reoort Nos.fjk317(318W2-801
REFERENCES:
(a)
Letter from Mr. T. T. Martin (NRC) to Mr.: G. C. Creel (BG&E),
Notice of Violation and Proposed Imposition of Civil Penalty -
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$50,000, dated August 7,1992 (b)
Letter from Mr. J. P. Dyrr (NRC) to Mr. G. C. Creel (BG&E),
i Enforcement Conference Summary - June 17, 1992, dated July 30, l-1992-(c)
Letter from Mr. M.' W. Hodges (NRC) to Mr. G. C. Creel (BG&E).
NRC Inspection Report Nox. 50-317/92-80; 50-318/92-80, dated June 5,1992 Gentlemen:
i Baltimore Gas and Eicctric Company's reply to the Notice of Violation contained in Reference (a) is =
l attached. - Also attached is a check in the full amount of the civil penalty imposed by the Nuclear -
Regulatory Commission.
s ye Upl4 f
jsR'238!!USlla7-i
-G r
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s Director, Office of Enforcement
- September 3,1992 Page.2 4
Should you have any further questions regarding this matter, we will be pleased to discuss them with yoa.
4 Very truly yours, e
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STATE OF MARYLAND :
- TO WIT:
COUNTY OF CALVERT I hereby certify that on the day of Sedambe 192, before me, the subscriber, a Notary Public of the State of Maryland in 'and for G loed Counki personally appeared George C. Creel, being duly sworn, and states that he is Seniof Vice President of the Baltimore Gas and Electric Company, a corporation of the State of Maryland; that he provides the foregoing response for the purposes therain set fonh: that the statements made are true and correct to the best of his knowledge, information nd belief; and that he was authorized to provide -
l the response on behalf of saiil Corporation.
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WITNESS my Hand and Notarial Scah Noiary Public My Commission Expires:
. M u ra A s 2 [f/
Date
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GCC/MDM;bjd Attachment cc:
Document Control Desk, NRC -
D. A. Brune, Esquire J. E. Silberg. Esquire R. A. Capra,-NRC D, G. Mcdonald, Jr., NRC 4
T. T. ' Martin, NRC P R. Wilson, NRC
' R. L McLean, DNR J. H. Walter, PSC 1
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4 AII4.0.IMENT(11 i
REPLYTO NOTICE OFVIOLATION INSPECTION REPORT NO,9].80/80 1-1.
VIOIATION OF 10 QR S0.46La)(1)(1) iEMERGENCY CQBILC_QOLING SYSTEM LEC.QS1 COOLING PERFORMANf.Q.
i ne Notice of Violation described in Reference (a) indicates Baltimore Gas and Electric?
Company (BG&E) failed to assure ECCS cooling performance in accordance wit! 10 CFR 50.46 (a)(1)(i). Specifically, BG&E failed to assure cooling performance for a range of small-btcak loss of coolant accidents (LOCAs) coinddent with a loss of offsite power (LOOP). In this scenario the potential existed for two majar loads to sequence on an Emergency Diesel:
Generator (EDG) simultaneously, due to EDG sequencer process-controlled loading design, 1
thus potentially degrading the emergency bus volWge below levels required to ensure lhe-l proper operation of safety equipment, A.
Admission or Denial of Ot.MJeced Violation The violation occurred as stated.
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1 B.
Feasons for the Violation.
l His violation occurred due to a failure to ensure a component designed to mitigate serious safety events, was able to perform under all required scenarios.- Analysts did not recognize prior to 1987 that bicak size would indirectly a!Tect the sequence of loads and could thereby challenge the diesel's ability to sustain emergency power.
Because this effort was unrecognized; a potentially critical range of break sizes waa 4
not analyzed. - Prior to 1987, we did not reco3nize the potential for sequencing major p
loads concurrently onto the EDGs. In 1987, a calculation was performed that x
indicated a problem existed, but due to a low probability of occurrence this scenario was considered to ham a very low safety significance. Thus a proposed modification L
to the sequencer, based on the results of the calculation, was not implemented.
l' C.
Corrective Steps that Itave Been Taken and Results Achieved.
In response to an NRC EDSFI question IlG&E concluded in March,1992 that a 1
degraded voltage coadition on safety equipn.cnt buses could occur during certain low probability accident s xnarios. After reaching this conclusion all three EDGs were declared inoperaNe on March 19,1992. With th6EDGs inoperable, an Unusual-Event was decimed foi Calvert Cliffs Unit 1 & 2 and both Units were shutdown from 100% power. Daring ' he shutdown period for each Unit, modifications were made to the Lost of Coolaut b,:ident (LOCI) sequencer to prevent out of sequence EDG loading. Subsequent calculations were performed which indicated that required ~
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safety functions would have successfully operated in the'as-found condition, thus confirming the low safety significance associated with this concern.
p D.
Corrective Steps That Will Be Taken to Avoid Further Violations.
As stated above, modifications were made to the LOCI sequencer to correct the EDG loading concern. Other load sequence scenarios were also considered and modifications were made where necessary. All corrective actions that will prevent further violations have been taken.
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4 ATTACIIMENT Q1 REPLY TO NOTICE OF YlOI.ATION INSPECTION REPORT NO 92 80/80 E.
Date When Full Compliance Will be Achieved.
I Full compliance was achieved after modifications and testing were completed cn both Units. After both Units were shutdown, Unit 1 entered a refueling outage and testing on the Unit I sequencer was c.ompleted on June 6,1992. Testing on Unit 2 was completed on April 1,1992.
II.
VIOLATIO.N OF 10 CFR PART 50.RPENDIX B CRITERION XVI (CORRECTIVE ACTIONL 10 CFR Part 50, Appendix B, Criterion XVI (Corrective Action), requires, in part, that measures be established to assure that conditions adverse to quality, such as failures, deficiencies, and deviations, are promptly identified and corrected. Contrary to the above, from January 1987 until M;rch 19,1992, BG&E identified a condition adverse to quality but did not properly correct it. Specifically, BG&E identified in January 1987, through a calculMion (E-87-1), the potential for degrading emergency bus voltages below levels required to ensure the proper operation of safety equipment but did not correct the condition ur.al it was identified by the NRC in March 1992.
A.
Admissipn or Denial of the Alleced Violation.
The violation occurred as stated.
H.
Reasons for the Violat;on.
i BG&E dispositioned this issue in 1987 based on a probabalistic safety approach without considering the determinis'.ic requirements of 10 CFR 50.46. As a result we did not modify the plant or obtain NRC concurrence for the condition to restore us to compliance. This was caused by weaknesses in our corrective action processes and i
a limited regulatory awareness.
This issue was first identified at Calvert Cliffs in 1987 after internal review of an -
INPO Operations and Maintenance Reminder (O&MR). The specific. concern detailed in the O&MR was not applicable to Calvert Cliffs. An evaluation of the generic issue revealed tu potential for safety system actuatica signals to occur after the expected time interval and carse a vulnerability to EDO transient overloading.
l Once identified, a significant amount of effort was put forth to analyze the issue. An electrical calculation was completed tc. detennine the effects on EDG vohage, and a proposed modification to the sequencers was developed.. At the same time a-complete Probabilistic Risk Assessment (PRA) was performed to chiculate the risk associated with this postulated accident scenario. The Plant Operations and Safety Review Committee (POSRC) recommended to the Plant Manager that the modification not be implemented based on 6 accident scenario's low probability of.
occurrence. After making this decision, ButE failed to seek NRC concurrence, resulting in a noncompliance with 10 CFR $0.46.
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The decision to not make modifications to the sequencers was a result of process weaknesse.s and deficient regulatory perspective. Our 1987 processes contributed to L
the failure to tecognize the regulatory aspects of this issue. Our corrective action-l 2
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ATTACIIMEN r (1)
REPLY TO NOTICE OF VIOLATION INSPECTION REPOI3T NO,92 80/80 processes at the time were fragmented, and issues were not uniformly evaluated for operability, reportaaility, and design impact. The primary focus of the Plant Operating Ex7mrience Assessment Committee (POEAC) was to evaluate potential safety concerns for applicability to Caived Cliffs. Regulatory compliance was not systematically considered by the committee.
Additionally our awareness of regulatory requiren,ents was incomplete. His was particularly true regarding regulatory acceptability os PRA in evaluating plant dc. sign.
PRA was a relatively new technique in 1987, and little guidance on its use had been written. The application of PRA to this issue was one of the first at Calvert Cliffs.
C.
Corrective Steps that linvc 11eca Taken and Results Achieved.
De current Calvert Cliffs processes used to handle issues of this type are sound and responsive. As part of our Performance Improveme< Plan (PIP), an Industry Operating Experience Group was created which evalums issues for applicability to Calvert Cliffs. It documents pertinent issues in hsue Reports - a comprehensive corrective action system which systematically causes each tssue to be screened for operability effect, reportability, and design impact.
Major steps have also been taken to improve the regulatory awareness and perspective of the plant staff. Special training was conducted on 10 CFR 50.59 design redew requirements in 1989 and 1990 for most of the engineering staff. The NRC's issuance of Generic Letter (GL) 91-18 was also noteworthy in upgrading our regulatory awareness. Operability asses: ment training incorporating the guidance of GL 91-18 was conducted in late 1991 and early this year. All of the above actions were completed between 1987 and discovery of the EDG issue in March 1992.
D, Corrective Steps That Willlie Taken to Avold Further Viohylons.
To ensure issues continue to be appropriately screened for operability concerns, an Operability Task Force is developing additional guidance in this area. The Task Force, comprised of representatives from semral groups, is using the guidance prosided in GL 91-18 as its basis. Continuing staff training m the areas of 10 CFR 50.59 reviews will also continue to strengthen the staff's ability to identify and resolve issues invahing licensing basis impact and regulatory significance.
A review of all PRA analyses conducted by BG&E was conducted to kmk for similar instances where design issues were dispositioned probabistically. None were found.
E.
Date When Full Compilance Wi!! be Achieved.
Full compliance was achieved after modifications and testing for the EDO sequencers were completed for both Units.
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