United States Nuclear Regulatory Commission - Protecting People and the Environment

EA-96-271 - Pilgrim 1 (Boston Edison Company)

October 21, 1996

EA 96-271

E. Thomas Boulette, PhD
Senior Vice President - Nuclear
Boston Edison Company
Pilgrim Nuclear Power Station
600 Rocky Hill Road
Plymouth, Massachusetts 02360-5599

SUBJECT:  NOTICE OF VIOLATION 
         (NRC INSPECTION REPORT NO. 50-293/96-07)

Dear Mr. Boulette:

This letter refers to the NRC inspection conducted from July 8 to July 12, 1996, and July 22 to July 26, 1996, at the Pilgrim Nuclear Power Station facility to review the circumstances surrounding an event reported to the NRC in Licensee Event Report (LER) 96-04, dated May 9, 1996, involving the potential degradation of primary containment integrity. The findings of the inspection were discussed with you and members of your staff during a telephone exit meeting on September 3, 1996. In addition, the NRC inspection report was sent to you with our letter, dated September 20, 1996. On October 3, 1996, a Predecisional Enforcement Conference was conducted with you and members of your staff to discuss the related violations, their causes, and your corrective actions.

Based on the information developed during the inspection, and the information provided during the conference, and by the LER, two violations of NRC requirements were identified. The violations are set forth in the enclosed Notice of Violation. The first violation involved the failure to maintain primary containment integrity in accordance with Technical Specification Section 3.7.A, in that two electrical containment penetrations were not properly protected due to improper trip-settings of 12 electrical penetration circuit breakers. Under certain high-impedance fault conditions during a postulated design basis accident, the trip settings, which were too high, could allow excessive current to pass through the electrical penetration circuits, thereby damaging the penetration seals, and causing the loss of primary containment integrity. This condition was discovered by your staff on April 9, 1996, following an investigation of a failed drywell-unit-cooler fan motor that was powered by electrical circuits passing through one of the two penetrations. When you discovered this condition, you declared primary containment inoperable and entered a 24-hour limiting condition for operation (LCO).

The second violation involved the failure to identify and correct this condition sooner, even though it existed as early as 1988 (and may have existed as far back as 1972). This constitutes a violation of 10 CFR Part 50, Appendix B, Criterion XVI, "Corrective Action" which requires, in part, that measures shall be established to assure conditions adverse to quality are promptly identified and corrected. For example, during a self-assessment that you performed in July 1991 of Pilgrim's electrical distribution system, your staff identified that electrical penetration protection for potential electrical faults within the primary containment had not been addressed. Although your staff later performed an operability evaluation to address this problem, the problem was not corrected because of an incorrect assumption regarding thermal overload of the motor starter, as described in the Notice. Therefore, the incorrect breaker trip-setting problem was not corrected. Later, in 1992, while performing a calculation for the purpose of evaluating the penetration under normal plant operation, your engineers noted that some of the circuits protected from overload by thermal relays were not adequately protected from short-circuits because the settings of magnetic-trip-only breakers exceeded National Electric Code (NEC) limits. Your engineers failed to pursue this further, and did not recognize that the circuit breaker manufacturer's technical manual required adherence to the NEC limits. In July 1993, your staff mischaracterized the corrective action for replacing the magnetic-trip-only breakers as enhancements, and therefore, the affected circuit breakers were not replaced until 1996.

The failure to maintain containment integrity under certain conditions, as well as the failure to identify this condition sooner, represent significant regulatory concerns. Therefore, these violations have been classified in the aggregate as a Severity Level III problem in accordance with the "General Statement of Policy and Procedure for NRC Enforcement Actions," (Enforcement Policy), NUREG-1600.

The NRC commends the technical inquisitiveness of the electrical engineer who identified this problem in 1996 during his follow-up review of a starter problem with a drywell area cooler. If not for his inquisitiveness, this problem likely would have remained uncorrected. Nonetheless, if similar inquisitiveness had been exhibited by your staff when opportunities existed in 1991, 1992, and 1993, this problem could have been corrected sooner. These findings demonstrate the need for management taking appropriate action to assure that your staff in general, and your engineers in particular, are sensitive to the importance of performing comprehensive evaluations whenever potential problems surface at the facility. Such reviews are needed to assure that all potentially degraded features are promptly identified and corrected.

In accordance with the Enforcement Policy, a base civil penalty in the amount of $50,000 is considered for a Severity Level III problem. Your facility has been the subject of escalated enforcement actions within the last 2 years (namely, a Severity Level III violation without a civil penalty issued on March 3, 1995, for failure to maintain containment integrity for approximately 30 days while the reactor was critical (EA 95-010)). Therefore, the NRC considered whether credit was warranted for Identification and Corrective Action in accordance with the civil penalty assessment process in Section VI.B.2 of the Enforcement Policy. Credit is warranted for identification since you identified the violation of Technical Specification Section 3.7.A. Credit is warranted for corrective action because your corrective actions were both prompt and comprehensive once the violations were identified in 1996. Your corrective actions included, but were not limited to (1) immediately entering the Technical Specification Limiting Condition of Operation; (2) correcting the trip-setting of the affected circuit breakers within four hours; (3) replacing all 12 magnetic-trip-only circuit breakers with thermal-magnetic type circuit breakers; and (4) completing a root cause evaluation, which identified additional corrective actions to be taken in the near future, namely establishing an improved tracking mechanism for periodic Long Term Plan (LTP) review, revising the calculation procedure to require verification that corrective actions are tracked, reviewing other calculations to determine if similar conditions exist, and reviewing the electrical engineering design guide to determine whether improvements should be made.

Therefore, to encourage prompt and comprehensive identification and correction of violations, I have been authorized, after consultation with the Director, Office of Enforcement, not to propose a civil penalty in this case. However, significant violations in the future could result in a civil penalty.

You are required to respond to this letter and should follow the instructions specified in the enclosed Notice when preparing your response. The NRC will use your response, in part, to determine whether further enforcement action is necessary to ensure compliance with regulatory requirements.

In accordance with 10 CFR 2.790 of the NRC's "Rules of Practice," a copy of this letter, and its enclosure will be placed in the NRC Public Document Room (PDR).

                            Sincerely, 



                            Hubert J. Miller
                            Regional Administrator 

Docket No. 50-293
License No. DPR-35

Enclosure: Notice of Violation

cc w/encl:
L. Olivier, Vice President - Nuclear and Station Director
T. Sullivan, Plant Department Manager
N. Desmond, Regulatory Relations
D. Tarantino, Nuclear Information Manager
R. Hallisey, Department of Public Health, Commonwealth of Massachusetts
The Honorable Therese Murray
The Honorable Linda Teagan
B. Abbanat, Department of Public Utilities
Chairman, Plymouth Board of Selectmen
Chairman, Duxbury Board of Selectmen
Chairman, Nuclear Matters Committee
Plymouth Civil Defense Director
P. Gromer, Massachusetts Secretary of Energy Resources
J. Shaer, Legislative Assistant
J. Fleming
A. Nogee, MASSPIRG
Regional Administrator, FEMA
Office of the Commissioner, Massachusetts Department of Environmental Quality Engineering
Office of the Attorney General, Commonwealth of Massachusetts
T. Rapone, Massachusetts Executive Office of Public Safety
Chairman, Citizens Urging Responsible Energy
Commonwealth of Massachusetts, SLO Designee


NOTICE OF VIOLATION
Boston Edison Company                                          Docket No. 50-293
Pilgrim Nuclear Power Station                                  License No. DPR-35
                                                               EA 96-271

During an NRC inspection conducted July 8-12, 1996 and July 22-26, 1996, for which a telephonic exit meeting was held on September 3, 1996, two violations of NRC requirements were identified. In accordance with the "General Statement of Policy and Procedure for NRC Enforcement Actions," NUREG 1600, the violations are listed below:

A. Technical Specification Section 3.7.A., "Primary Containment Integrity," requires, in part, that the primary containment integrity shall be maintained at all times when the reactor is critical.

Contrary to the above, for an indeterminate but extended period prior to April 9, 1996, primary containment integrity was not maintained in that two electrical containment penetrations (Nos. Q105A and Q105B) were not properly protected due to improper trip-settings on the circuit breakers for the two affected electrical-penetrations. Specifically, under certain high-impedance electrical fault conditions during a postulated design basis accident, the trip settings for the circuit breaker, which were set too high, could allow excessive current to pass through the electrical penetration circuits, damaging the penetration seals, and causing the primary containment to loose its integrity. (IFS 01013)

B. 10 CFR 50, Appendix B, Criterion XVI, "Corrective Action," requires, in part, that measures shall be established to assure conditions adverse to quality such as deficiencies, deviations, and nonconformances are promptly identified and corrected.

Contrary to the above, prior to April 9, 1996, measures were not established to assure that conditions adverse to quality were promptly identified and corrected. Specifically, a condition existed, at a minimum, from 1988 (and possibly as far back as the before initial startup in 1972) in which 12 circuit breakers (magnetic-trip-only breakers) for two electrical penetrations (Nos. Q105A and Q105B) had been set improperly, and the licensee did not identify this condition adverse to quality until 1996. The condition adverse to quality involved the failure to maintain primary containment integrity in that under certain high-impedance electrical fault conditions during a postulated design basis accident, the trip-settings of the circuit breakers, which were set too high, could allow excessive current to pass through the electrical penetration circuits and damage the electrical penetration seals, causing a loss of primary containment integrity. The licensee had at least three opportunities to identify and correct this condition prior to 1996, but did not do so, as described below:

  1. In July 1991, during a self-assessment that the licensee performed of Pilgrim's electrical distribution system, the licensee identified that electrical penetration protection for potential electrical faults within the primary containment had not been addressed for Pilgrim Station. Although the licensee performed an operability evaluation to address this problem at that time, the evaluation was based on an incorrect assumption that the 1300 percent thermal overload of the motor starters (for the motors powered by the 12 affected electrical circuits) could provide adequate protection of the circuits. Therefore, the incorrect breaker trip setting problem was not corrected at that time.
  2. In 1992, while performing calculation PS-119 for the purpose of evaluating electrical penetrations under normal plant operation, the licensee noted that some of the circuits protected from overload by thermal relays, were not adequately protected from short-circuits because the settings of the magnetic-trip-only circuit breakers exceeded National Electric Code (NEC) limits. The licensee failed to pursue this further to identify that the circuit breaker manufacturer's technical manual required adherence to the NEC limits. Therefore, the licensee again failed to correct the improper trip setting of the breakers.
  3. In July 1993, the licensee initiated action to resolve the 1991 self-assessment findings by developing plans to replace the magnetic-trip-only breakers. However, licensee staff mischaracterized the corrective actions as enhancements, and therefore, the affected circuit breakers were not replaced until 1996. (IFS 01023)

These violations represent a Severity Level III problem (Supplement I).

Pursuant to provisions of 10 CFR 2.201, Boston Edison Company is hereby required to submit a written statement or explanation to the U.S. Nuclear Regulatory Commission, ATTN: Document Control Desk, Washington, D.C. 20555 with a copy to the Regional Administrator, Region I, and a copy to the NRC Resident Inspector at the facility that is the subject of this Notice, within 30 days of the date of the letter transmitting this Notice of Violation (Notice). This reply should be clearly marked as a "Reply to a Notice of Violation" and should include for each violation: (1) the reason for the violation, or, if contested, the basis for disputing the violation, (2) the corrective steps that have been taken and the results achieved, (3) the corrective steps that will be taken to avoid further violations, and (4) the date when full compliance will be achieved. Your response may reference or include previous docketed correspondence, if the correspondence adequately addresses the required response. If an adequate reply is not received within the time specified in this Notice, an order or Demand for Information may be issued as to why the license should not be modified, suspended, or revoked, or why such other actions as may be proper should not be taken. Where good cause is shown, consideration will be given to extending the response time.

Under the authority of Section 182 of the Act, 42 U.S.C. 2232, this response shall be submitted under oath or affirmation.

Because your response will be placed in the NRC Public Document Room (PDR), to the extent possible, it should not include any personal privacy, proprietary, or safeguards information so that it can be placed in the PDR without redaction. If personal privacy or proprietary information is necessary to provide an acceptable response, then please provide a bracketed copy of your response that identifies the information that should be protected and a redacted copy of your response that deletes such information. If you request withholding of such material, you must specifically identify the portions of your response that you seek to have withheld and provide in detail the bases for your claim of withholding (e.g., explain why the disclosure of information will create an unwarranted invasion of personal privacy or provide the information required by 10 CFR 2.790(b) to support a request for withholding confidential commercial or financial information). If safeguards information is necessary to provide an acceptable response, please provide the level of protection described in 10 CFR 73.21.

Dated at King of Prussia, Pennsylvania
this 21st day of October 1996

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