IR 05000331/1993021
| ML20059K476 | |
| Person / Time | |
|---|---|
| Site: | Duane Arnold  |
| Issue date: | 01/19/1994 |
| From: | Martin J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Leslie Liu IES UTILITIES INC., (FORMERLY IOWA ELECTRIC LIGHT |
| Shared Package | |
| ML20059K477 | List: |
| References | |
| EA-93-255, NUDOCS 9402020115 | |
| Download: ML20059K476 (5) | |
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UNITED STATES -
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USLE. ILUNOIS 60532-4351
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January 19, 1994 Docket No. 50-331 License No. DPR-49 EA 93-255 lowa Electric Light and Power Company ATIN:
Mr. Lee Liu Chairman of the Board and Chief Executive Officer IE Towers p
0. Box 351 Cedar Rapids, IA 52406
Dear Mr. Liu:
SUBJECT: NOTICE OF VIOLATION (INSPECTION REPORT NO. 50-331/93021)
This refers to the inspection conducted from August 24 through October 14,.
1993, at the Duane Arnold Energy Center.
The inspection reviewed the circumstances surrounding the inoperability of the
"B" standby diesel generator (SBDG) for greater than 7 days without the plant being taken to cold shutdown in accordance with technical specifications (TS), and the inoperability of the "A" onu 7" SBDGs during core alterations, also contrary to TS.
The report documenting this inspection was sent to you by letter dated November 5, 1993. An enforcement conference was held on November 19, 1993, and a report summarizing the conference was sent to you by letter dated December 19, 1993.
On July 21, 1993, with the plant operating at approximately 75 percent power, routine preventive maintenance was performed on the standby transformer supply circuit breaker in accordance with plant approved maintenance procedures.
Due to an inadequate circuit breaker maintenance procedure and poor post-maintenance testing, a critical dimension important to the operation of the circuit breaker's auxiliary contacts was not verified.
In the as-left condition, an auxiliary contact on the standby transformer supply breaker that provided position indication to the "B" SBDG circuit breaker automatic closing logic indicated that the supply breaker was closed, when it was actually open.
This made the "B" SBDG inoperable because its circuit breaker would not automatically close on a loss of power to essential bus IA4.
It remained that way until it was discovered on September 22, 1993.
Technical specifications required that if one SBDG was inoperable, continued reactor operation was permissible for the succeeding 7 days.
If the SBDG was not repaired within that time, then the reactor should have been taken to hot shutdown within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> after expiration of 7 days (July 28) and then taken to cold shutdown within the following 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
This was not done and therefore was a violation of the TS. On July 29 the reactor was shut down for a refueling outage, and on July 31 it was taken to cold shutdown.
9402020115 940119-PDR ADOCK 05000331 G
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Iowa Electric Light & Power
January 19, 1994 In addition to the
"B" SBDG exceeding the 7 day limiting condition for operation (LCO), on August 4 the "A" SBDG was taken out of service to perform planned maintenance; it was returned to service on August 22.
During that time, from August 7-11, the core was unloaded as part of the refueling outage activities. The TS required that during core alterations, one SBDG must always remain operable. Otherwise, core alterations were not permitted.
Therefore, from August 7-11, 1993, with core alterations in progress and both of the SBDGs inoperable, the IS again were violated.
Collectively, these two violations represent a significant failure to comply with the action statements for a TS limiting condition for operation.
Therefore, in accordance with the " General Statement of Policy and Procedure for NRC Enforcement Actions," (Enforcement Policy) 10 CFR Part 2, Appendix C, these violations are classified in the aggregate as a Severity Level III problem.
The potential safety significance of the violations is that during this time, the "B" SBDG would not have been able to automatically supply power to essential bus lA4 if offsite power had been lost.
However, the actual safety significance was mitigated by the fact that the loss of the essential bus would have been easily recognized by the reactor operators, and the output breaker could have been manually closed from the control room. This was verified when you ran a " blind" test on the simulator with two operating crews and they both identified the failure and reenergized the bus within.5 minutes.
At the enforcement conference we acknowledged your corrective actions for the j
violations.
These included, but were not limited to: determining which 4160 i
Vac circuit breakers had been adjusted in the past and promptly verifying the
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function of any. contact not previously tested since maintenance was last performed; measuring all 49 of the 4160 Vac circuit breakers using dimensional
checks developed in cooperation with General Electric (GE);
and publicizing the problem on the INP0 Notepad system.
You also assigned two people full time to check the DAEC maintenance procedures line-by-line against the GE manuals; conducted a meeting with two other utilities at Arkansas Nuclear One; and discussed the issue with GE which resulted in GE committing to issue a i
service action letter on the issue.
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Nevertheless, we are concerned with these violations. A significant part of the problem appears to be a lack of involvement and questioning attitude by your staff in resolving plant problems and issues, and in communicating with each other.
For example, it does not appear that your engineering staff was adequately involved in the maintenance procedure development, the changing of dimensional tolerances, the assignment of post maintenance test requirements, and the initial analysis of the breaker contact failure for this important safety equipment. Also, your initial corrective actions, burnishing of breaker contacts, did not reflect a comprehensive evaluation of the failure i
and delayed identification of the actual cause.
Furthermore, the maintenance
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procedures used for this activity did not incorporate the applicable manufacturer's technical information addressing the proper dimensional tolerances of these breakers and utilized an imprecise technique for determining the dimensional tolerances. These problems contributed i
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Iowa Electric Light & Power
J nuary 19, 1994 significantly to the breaker's failure to function properly. Also the changes made to the dimensional tolerances through the addition of spacers were not adequately questioned and evaluated for their affect on performance of the breakers. We are concerned that this event and a fire which disabled a safety related river water breaker approximately a year earlier, may reflect a lack of proper concern for the significance of changes to electrical safety equipment. These failures are unacceptable and must be corrected.
In accordance with the " General Statement of Policy and Procedure for NRC Enforcement Actions," (Enforcement Policy) 10 CFR Part 2, Appendix C, a civil penalty is considered for a Severity Level III problem. However, I have been authorized, after consultation with the Director, Office of Enforcement not to propose a civil penalty in this case after application of the escalation and mitigation factors.
The civil penalty was fully mitigated based on your demonstrated initiative in finding the root cause of the problem, comprehensive corrective actions, and improved plant performance over the last 24 months and to encourage you to continue with your efforts to improve this performance.
Furthermore,.the problems that you experienced do not appear to be isolated to DAEC.
A quick survey of about six other plants indicated that half of them may have similar-problems. As a result, the NRC has issued Information Notice 93-91 to alert other licensees to the problem.
The other adjustment factors in the Policy were considered and no further adjustment to the base civil penalty was considered appropriate.
You are required to respond to this letter and should follow the instructions specified in the enclosed Notice of Violation (Notice) when preparing your
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response.
In your response, you should document the specific actions taken and any additional actions you plan to prevent recurrence.
You should include your plans to involve Engineering Department personnel at an early stage of plant problems or changes to prevent the kinds of problems experienced in this After reviewing your response to this Notice, including your proposed case.
corrective actions and the results of future inspections, the NRC will determine whether further NRC enforcement action is necessary to ensure compliance with NRC regulatory requirements.
In accordance with 10 CFR 2.790 of the NRC's " Rules of Practice," a copy-of this letter, its enclosure, and your responses will be placed in the NRC Public Document Room.
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Iowa Electric Light & Power
January 19, 1994 The responses directed by this letter and the enclosed Notice are not subject to the clearance procedures of the Office of Management and Budget as required by the Paperwork Reduction Act of 1980, Public Law No.96-511.
Sincerely,
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r John B. Martin Regional Administrator Enclosure: Notice of Violation cc w/ enclosure:
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D. Wilson, Plant
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Superintendent - Nuclear
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K. Young, Manager, Nuclear Licensing e
OC/LfDCB Resident Inspector, Rill Stephen Brown,-lowa Dept.
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'HThompson, DEDS JSniezek, DEDR JLieberman, OE LChandler, OGC JGoldberg, OGC 1Murley, NRR JCallen, NRR Enforcement Coordinators RI, RII, RIV, RV FIngram, GPA/PA DWilliams, 0IG BHayes, 01 EJordan, AE0D
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