EA-96-488 - Cooper (Nebraska Public Power District)

December 20, 1996

EA 96-487
EA 96-488

G. R. Horn, Senior Vice President
of Energy Supply
Nebraska Public Power District
1414 15th Street
Columbus, Nebraska 68601


Dear Mr. Horn:

An NRC inspection was conducted November 4-8, and December 4, 1996, at your Cooper Nuclear Station reactor facility. The inspection focused on the regulatory and safety significance of your identification of a design flaw in the reactor core isolation cooling system and of your practice of performing full core offloads during refueling operations.

Based on the results of this inspection, three violations of NRC requirements were identified. These violations are cited in the enclosed Notice of Violation (Notice) and the circumstances surrounding the violations are described in detail in the enclosed report. The first violation, involving failure to meet station blackout requirements, was classified as Severity Level III, indicating a significant regulatory concern (EA 96-488). However, because you independently identified and corrected the concern, as further discussed below, no civil penalty is being assessed. Further, the NRC has concluded that information regarding the reason for the violation, the corrective actions taken to correct the violation and prevent recurrence, is already adequately addressed on the docket in Licensee Event Report 94-018. Therefore, you are not required to respond to this violation unless the description in this report does not accurately reflect your corrective actions or your position. In that case, or if you choose to provide additional information, you should follow the instructions specified in the enclosed Notice. As discussed with Mr. Brad Houston of your staff on December 4, 1996, the NRC did not believe a predecisional enforcement conference was necessary to address this issue because no additional information was needed to make an enforcement decision. The remaining violations, related to design and operation of your spent fuel pool cooling systems, were classified at Severity Level IV and do require a response (EA 96-487). These violations are of concern because they are examples of not maintaining the licensing basis of the plant and not ensuring the facility is operated in accordance with the licensing basis.

The violation of 10 CFR 50.63, the station blackout rule (Violation A in the enclosed Notice), is a significant regulatory concern not only because the ability of the reactor core isolation cooling (RCIC) system to function in a station blackout was adversely affected, but because it was caused, in part, by a failure to understand and maintain plant design configurations. Thus, the fact that an AC motor had been installed on the RCIC trip throttle valve was not recognized when the station blackout rule was addressed in 1991 and plant personnel erroneously assumed that the RCIC system would function independently of AC power. Therefore, this violation has been categorized in accordance with the "General Statement of Policy and Procedure for NRC Enforcement Actions" (Enforcement Policy), NUREG-1600, at Severity Level III.

In accordance with the Enforcement Policy, a civil penalty with a base value of $50,000 is considered for a Severity Level III violation. Because your facility was the subject of escalated enforcement actions within the last 2 years, as well as during the 2 years that preceded the discovery of this issue, 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. Because this violation was discovered by your staff as a result of comprehensive surveillance procedure reviews and resulted in prompt and comprehensive corrective action, as described in Licensee Event Report 94-018, the NRC has determined that credit is warranted for both factors.

Therefore, to encourage the identification, and prompt and comprehensive correction, of safety concerns and 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 of this nature in the future could result in a civil penalty.

In preparing your response to Violations B and C, you should follow the instructions specified in the enclosed Notice. 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, its enclosures, and your response (if you choose to provide one) will be placed in the NRC Public Document Room (PDR). To the extent possible, your response should not include any personal privacy, proprietary, or safeguards information so that it can be placed in the PDR without redaction.

Should you have any questions concerning this inspection, we will be pleased to discuss them with you.

Sincerely, J. E. Dyer, Director Division of Reactor Projects

Docket No.: 50-298
License No.: DPR-46

1. Notice of Violation
2. NRC Inspection Report 50-298/96-30

cc w/enclosures:
John R. McPhail, General Counsel
Nebraska Public Power District
P.O. Box 499
Columbus, Nebraska 68602-0499

P. D. Graham, Vice President of
Nuclear Energy
Nebraska Public Power District
P.O. Box 98
Brownville, Nebraska 68321

B. L. Houston, Nuclear Licensing
and Safety Manager
Nebraska Public Power District
P.O. Box 98
Brownville, Nebraska 68321

R. J. Singer, Manager-Nuclear
Midwest Power
907 Walnut Street
P.O. Box 657
Des Moines, Iowa 50303

Mr. Ron Stoddard
Lincoln Electric System
11th and O Streets
Lincoln, Nebraska 68508

Randolph Wood, Director
Nebraska Department of Environmental
P.O. Box 98922
Lincoln, Nebraska 68509-8922

Nemaha County Board of Commissioners
Nemaha County Courthouse
1824 N Street
Auburn, Nebraska 68305

Cheryl Rogers, LLRW Program Manager
Environmental Protection Section
Nebraska Department of Health
301 Centennial Mall, South

Lincoln, Nebraska 68509-5007

Dr. Mark B. Horton, M.S.P.H.
Nebraska Department of Health
P.O. Box 950070
Lincoln, Nebraska 68509-5007

R. A. Kucera, Department Director
of Intergovernmental Cooperation
Department of Natural Resources
P.O. Box 176
Jefferson City, Missouri 65102

Kansas Radiation Control Program Director


Nebraska Public Power District Docket No. 50-298 Cooper Nuclear Station License No. DPR-46 EAs 96-487 & 96-488

During an NRC inspection conducted on November 4 through December 4, 1996, three 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. 10 CFR 50.63, Loss of all alternating current power, requires that each nuclear power plant must be able to withstand for a specified duration and recover from a station blackout as defined in 10 CFR 50.2. It further states that the reactor core and associated coolant, control, and protection systems . . . . must provide sufficient capacity and capability to ensure that the core is cooled . . . .

In response to NRC questions regarding the licensee's Station Blackout (SBO) Analysis, the licensee responded in a September 30, 1991, letter to the Commission that the "SBO evaluation for CNS assumes that HPCI and RCIC are available and that both start automatically at the onset of the event. However, the current evaluation assumes that HPCI is secured after one cycle of operation to further conserve battery energy. Thereafter, reactor vessel level would be primarily controlled by automatic operation of the RCIC system. One cycle of HPCI is sufficient to stabilize level, with no loss of coolant coverage of the core expected. The RCIC system is considered sufficient to maintain water level beyond this point."

Contrary to the above, on August 20, 1994, the licensee discovered that the reset function for Valve RCIC-MOV-MO14, the RCIC turbine trip/throttle valve, was powered by an ac, not a dc motor. Reactor vessel level could not be automatically controlled by the RCIC system and core cooling could have been affected (01013).

This is a Severity Level III violation. (Supplement 1) (298/96030-01)

No response is required to this violation.

B. 10 CFR 50.59(a)(1) states, in part, that a licensee may make changes in the facility as described in the safety analysis report without prior Commission Approval unless the change involves a change in the Technical Specifications incorporate in the license or an unreviewed safety question. 10 CFR 50.59(b)(1) states, in part, that the licensee shall maintain records of changes in the facility, to the extent that these changes constitute changes in the facility as described in the safety analysis, and that these records must include a written safety evaluation which provides the basis for the determination that the change did not involve an unreviewed safety question.

On October 20, 1995, the licensee's FSAR, Section 8.5.6, stated, in part, that "the residual heat removal (RHR) system can be intertied with the Fuel Pool cooling system if required. This capability increases the spent fuel pool cooling capacity in the event that such additional capacity is necessitated by removal from the core of an unusually large number of fuel elements. The RHR system - fuel pool cooling system intertie is sized to remove an emergency heat load . . . from the fuel pool which corresponds to full core off-loading plus the batch of spent fuel discharged at the previous refueling outage.

In the NRC's safety evaluation supporting License Amendment 52 dated September 29, 1978, it was indicated in Section 2.2 that the RHR cooling would be available when performing full core offloads.

Contrary to the above, on October 20, 1995, the licensee changed the facility as described in the safety analysis report in that the facility was not operated as described in the FSAR and a written safety evaluation of the change from the FSAR had not been performed to determine whether this change involved an unreviewed safety question. Specifically, the licensee was in the process of performing a full core offload, and the RHR system was not available to assist the fuel pool cooling system in removing what the FSAR characterized as an emergency offload (02014).

This is a Severity Level IV violation. (Supplement 1) (298/96030-02)

C. Criterion III of Appendix B to 10 CFR Part 50 requires that regulatory requirements and the design basis, as defined in 10 CFR 50.2 and as specified in the license application, for those structures systems and components to which the appendix applies are correctly translated into specifications, drawings, procedures, and instructions.

In the safety evaluation report which accompanied Amendment 52 to the facility operating license, the NRC staff acknowledged that the licensee's spent fuel pool and cooling systems were capable of handling the heat load associated with a full core discharge. However, this acknowledgement was based on certain design assumptions. In the Safety Evaluation Report, the staff stated that the maximum fuel pool heatload was associated with an offload that would occur 13 days after shutdown.

Contrary to the above, the design basis assumption that the maximum heat load was associated with full core discharge which was completed in 13 days was not translated into procedures. Procedure 2.3.2, "Fuel Pool Cooling and Demineralizer System," contained no administrative controls to ensure that fuel was not loaded at a rate that would exceed the 13-day assumption. In October 1995, the licensee did exceed this offload rate (03014).

This is a Severity Level IV violation. (Supplement 1) (298/96030-03)

No response is required for Violation A. For Violations B and C, a response is required in accordance with regulations as described below.

Pursuant to the provisions of 10 CFR 2.201, Nebraska Public Power District 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 IV, 611 Ryan Plaza Drive, Suite 400, Arlington, Texas 76011, 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 a Demand for Information may be issued as to why the license should not be modified, suspended, or revoked, or why such other action as may be proper should not be taken. Where good cause is shown, consideration will be given to extending the response time.

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. However, if you find it necessary to include such information, you should clearly indicate the specific information that you desire not to be placed in the PDR and provide the legal basis to support your request for withholding the information from the public.

Dated at Arlington, Texas
this 20th day of December 1996

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