ML18153A816
| ML18153A816 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 05/15/1995 |
| From: | Ohanlon J VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 95-204, NUDOCS 9505220191 | |
| Download: ML18153A816 (5) | |
Text
VIRGINIA ELECTRIC AND POWER COMPANY RICHMOND, VIRGINIA 23261 May 15, 1995 United States Nuclear Regulatory Commission Attention: Document Control Desk Washington, D. C. 20555 Gentlemen:
VIRGINIA ELECTRIC AND POWER COMPANY SURRY POWER STATION UNIT 1 AND UNIT 2 REPLY TO A NOTICE OF VIOLATION Serial No.
SPS/VLA/GDM Docket Nos.
License Nos.95-204 R6 50-280 50-281 DPR-32 DPR-37 NRC INSPECTION REPORT NOS. 50-280/95-06 AND 50-281/95-06 We have reviewed your Inspection Report Nos. 50-280/95-06 and 50-281/95-06 dated April 14, 1995, and the enclosed Notice of Violation (NOV). The inspection report identified a violation for exceeding the pressurizer Technical Specifications heatup rate for Surry Unit 2. Although we agree with the violation as stated in the NOV, we believe this violation meets the criteria for a non-cited violation as stated in 10 CFR 2, Appendix C, Vll.8(2).
The violation was promptly identified by the licensee as a result of increased monitoring of the pressurizer cooldown rate by operations personnel during Reactor Coolant System (RCS) cooldown activities. The additional monitoring was being performed in response to recent industry events in which excessive RCS cooldowns occurred. The violation was not safety significant, and prompt corrective actions have been implemented, including initiating an engineering evaluation and instituting actions to prevent recurrence. In fact, prompt restoration of temperature limits and performance of an engineering evaluation to determine. the effects of exceeding the limit is the required action specified in Standard Technical Specifications for this condition. Furthermore, excessive RCS heatups and cooldowns are a recent generic issue in the industry and are currently being evaluated for additional industry action by the Westinghouse Owners Group. Therefore, we request reclassification of the cited Level IV violation to a non-cited violation in accordance with the NRC Enforcement Policy.
Separately, our response to the NOV is provided in the attachment.
We have no objection to this letter being made a part of the public record. Please contact us if you have any questions or require additional information.
Very truly yours,
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James P. O'Hanlon Senior Vice President - Nuclear I
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U.S. Nuclear Regulatory Commission Region II 101 Marietta Street, N.W.
Atlanta, Georgia 30323 Mr. M. W. Branch NRG Senior Resident Inspector Surry Power Station
REPLY TO A NOTICE OF VIOLATION NRC INSPECTION CONDUCTED MARCH 5 THROUGH APRIL 1, 1995 SURRY POWER STATION UNITS 1 AND 2 INSPECTION REPORT NOS. 50-280/95-06 AND 50-281/95-06 NRC COMMENT:
"During an NRG Inspection conducted on March 5 through April 1, 1995, a violation of NRG requirements was identified. In accordance with the 'General Statement of Policy and Procedure for NRG Enforcement Actions,' 1 O CFR Part 2, Appendix C, the violation is listed below:
Technical Specification 3.1.B.3 requires that the pressurizer heatup rate not exceed 100 degrees Fahrenheit (F) per hour.
Contrary to the above, on February 4, 1995, the Unit 2 pressurizer heatup rate exceeded 100 degrees Fin a one hour period. From 10:30 a. m. to 11 :30 a. m.
the temperature in the pressurizer increased from 254 to 400 degrees F.
This is a Severity Level IV violation (Supplement I)."
l -
REPLY TO A NOTICE OF VIOLATION NRC INSPECTION CONDUCTED MARCH 5 THROUGH APRIL 1, 1995 SURRY POWER STATION UNITS 1 AND 2 INSPECTION REPORT NOS. 50-280/95-06 AND 50-281/95-06 Reason for the Violation, or if Contested, the Basis for Disputing the Violation Unit 2 had entered its Cycle 12 refueling outage and was being maintained at Cold Shutdown conditions with a bubble in the pressurizer. Operators *were *performing various evolutions including slow controlled cooldown of the RCS, degasification of the RCS and setup for Engineered Safety Feature logic testing. The evolutions in
.progress resulted in minor out-surges from the pressurizer and in-surges of relatively cooler RCS liquid into the pressurizer. The pressurizer liquid space Resistance Temperature Detector (RTD) located near the bottom of the pressurizer monitored the thermal effect of these low-volume in-surges and out-surges.
In one case, the resulting temperature changes at the RTD exceeded the Technical Specification (TS) pressurizer heatup rate limit.
The RCS cooldown general operating procedure had been revised prior to the Unit 2 outage as a result of a recent industry event at another utility* that involved an excessive pressurizer cooldown associated with the evolution for collapsing the pressurizer bubble.
The industry event specifically emphasized monitoring for excessive pressurizer cooldowns during normal RCS cooldown evolutions.
Consequently, the procedure revision incorporated precautions for excessive cooldown rates and a change to specifically document pressurizer temperatures and verification of cooldown rates every 30 minutes. During the evolutions described above, control room operators monitored the cooldown rates for compliance with
- procedure and TS requirements. However, a review of the data recorded in the procedure determined that the Technical Specifications (TS) limit for pressurizer heatup had been exceeded during an out-surge.
Exceeding the pressurizer heatup rate TS limit was caused by a lack of adequate procedural controls for both pressurizer in-surges and out-surges during the RCS cooldown evolutions. Based on the recent industry operating experience information, the pressurizer heatup of the significance seen during this event was not anticipated by the procedure nor by the operators.
Corrective Steps Which Have Been Taken and the Results Achieved Operating procedures for RCS heatup and cooldown were revised to ensure pressurizer heatup and cooldown rate limits are more closely monitored and maintained within the TS pressurizer heatup and cooldown limits.
A review was conducted of available heatup and cooldown data to determine if there were any previous instances where either the pressurizer heatup or cooldown limits had been exceeded. No other examples were identified.*
Plant data for the event was supplied to Westinghouse to determine whether the structural integrity of the pressurizer was affected due to the temperature transient.
Their analysis concluded that the transient did not adversely affect the structural integrity of the pressurizer and that continued operation was acceptable.
The Westinghouse analysis was independently reviewed by Virginia Power.
A Licensee Event Report (LER Report No. 50-281/95-001 dated March 3, 1995) was prepared in accordance with 10 CFR 50.73. An Operating Experience (OE) report was also issued.
Corrective Steps That Will Be Taken to Avoid *Recurrence A review of procedures that could result in in-surges and out-surges of reactor coolant into and out of the pressurizer is being conducted. Based on the results of this review, procedural enhancements will be made as required.
As part of our independent operating experience review program, we are currently reviewing the RCS heatup and cooldown events at Surry and within the industry to determine if additional measures should be considered to further prevent or mitigate excessive pressurizer heatups or cooldowns.
Upon completion of their review, additional preventive measures will be implemented as necessary.
The Westinghouse Owners Group (WOG) has created a task team on pressurizer in-surge and out-surge thermal transients. The WOG is currently collecting data on pressurizer heatup and cooldown rates at three test plants. As part of this study, these plants are using Westinghouse operating strategies developed to mitigate these transients. The final results of the WOG study will be evaluated for applicability to Surry as part of our operating experience review program.
Training will be conducted prior to the next Unit 1 refueling outage planned for the fall of 1995. The training will focus on the causes and effects of in-surges and out-surges to the pressurizer.
This training will include management, technical staff and operations personnel.
The Date When Full Compliance Will Be Achieved Full compliance has been achieved. Procedures for controlling RCS heatup and cooldown evolutions have be revised to ensure pressurizer heatup and cooldown TS limits will not be exceeded.