ML18067A709
| ML18067A709 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 10/09/1997 |
| From: | Thomas J. Palmisano CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 50-255-97-08, 50-255-97-8, NUDOCS 9710150161 | |
| Download: ML18067A709 (6) | |
Text
Consumers Ener9i')>
October 9, 1997 U.S. Nuclear Regulatory Commission ATIN: Document Control Desk Washington, DC 20555 DOCKET 50-255 - LICENSE DPR PALISADES PLANT
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.-.:.... s: c -5..: J~25 Tlloma* J. Palmluno Site Vice President REPLY TO NOTICE OF VIOLATION 50-255/97008 PLANT PROCEDURES ALLOW STEADY STATE POWER LEVEL GREATER THAN LICENSE LIMIT NRC Inspection Report No. 50-255/97008(DRP) dated September 5, 1997, contained a Notice of Violation for a Severity Level IV violation concerning the potential to exceed the licensed full power limit. Attachment 1 contains our response to the violation. The response to the violation was required to be submitted within 30 days from the date of the letter transmitting the violation. Discussion with Bruce Burgess at Region Ill on September 23, 1997, confirmed that the 30-day requested response could be provided within 30 days of receipt of the letter, which was September 11, 1997. '-
The inspection cover letter also noted a continuing weakness with post maintenance testing and an example of weak ALARA planning. These two weaknesses are being addressed and status of our efforts in this area will be submitted in a separate letter.
9710150161 6§688~55
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SUMMARY
OF COMMITMENTS This letter contains no new commitments and no revisions to existing commitments.
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Thomas J. Palmisano Site Vice President CC Administrator, Region Ill, USNRC Project Manager, NRR, USNRC NRC Resident Inspector - Palisades Attachment 2
ATTACHMENT 1 CONSUMERS ENERGY COMPANY PALISADES PLANT DOCKET 50-255 REPLY TO NOTICE OF VIOLATION PLANT PROCEDURES ALLOW STEADY STATE POWER LEVEL GREATER THAN LICENSE LIMIT 3 Pages
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NRC VIOLATION During an NRG inspection conducted on May 24 through July 7, 1997, one violation of NRG requirements was identified. In accordance with the "General Statement of Policy and Procedure for NRG Enforcement Actions," NUREG 1600, the violation is listed below:
10 CFR 50, Appendix B, Criterion V, "Instructions, Procedures, and Drawings,"
requires, in part, that activities affecting quality shall be prescribed by documented instructions, procedures, or drawings, of a type appropriate to the circumstances and shall be accomplished in accordance with these instructions, procedures and drawings.
Palisades Plant Facility Operating License, section 2.c.(1), states, in part, that "CPCo is authorized to operate the facility at steady-state reactor core power levels not in excess of 2530 megawatts thermal (100 percent rated power) in accordance with the conditions specified herein."
Contrary to the above, on February 7, 1996, the operations shift conducted an activity affecting quality, the delithiation of the Reactor Coolant System, using General Operating Procedure (GOP)-12, Revision 12, Section 5. 3. 1 a, a procedure inappropriate to the circumstances in that it allowed plant operators to operate the plant at 100.99 percent power (2555 megawatts thermal}, a steady state power level greater than the license limit.
This is a Severity Level IV violation (Supplement I)
CONSUMERS ENERGY COMPANY RESPONSE Consumers Energy agrees that the facts are as stated. General Operating Procedure (GOP) -12 as written would have allowed plant operators to operate the plant at a steady state power level greater than the license limit. Uncertainty analyses combined with follow..:up ultrasonic flow measurements, however, reveal that neither the licensing nor design bases were exceeded throughout this event.
BACKGROUND On February 7, 1996, during a planned delithiation of the reactor coolant system, a slight increase in the plant power level was observed. The power level was controlled and monitored in compliance with the existing procedures and resulted in an indicated 1
plant power level slightly in excess of 100% of licensed power for nine consecutive hours. Initial investigation of the involved measurement uncertainties led to the event being reported as LER 96-006 on March 11, 1996, as a condition possibly outside of the design basis and in violation of a license condition which requires that the plant not be operated in excess of 2530 Megawatts thermal (100% rated power levels).
Palisades' procedures had considered this license condition steady state limit to be met if reactor power averaged over 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> was below 2530 megawatts. Minor excursions above 100 percent power were viewed as acceptable as long as peak power did not exceed 101 percent and the 24-hour average power was less than 2530 megawatts.
The slow power rise during delithiation was viewed as a transient condition not subject to the steady state limit specified in the license. During a later review of power level records, questions were raised about whether 24~hour averaging was the appropriate standard to assure license compliance, and whether measurement uncertainties were adequately considered in the procedure limit on peak power.
Subsequent tests and analyses have shown that Palisades did not exceed the 10 CFR 50.2 design basis and did not exceed 100% power during the period in question. This conclusion was reported to the NRC on August 2, 1996, as Supplement 1 to LER 96-006.
EVENT ANALYSIS Two separate actions were taken during the investigation of this event. These actions were:
- 1.
The calorimetric uncertainty analysis was redone to more accurately reflect the calorimetric uncertainty. This analysis was rigorously reviewed by Consumers Energy Company and an outside contractor with significant experienc~ in uncertainty analyses.
- 2.
An ultrasonic flow measurement (UFM) of the feedwater flow was performed on May 21-22, 1996 to assess the plant thermal performance. The UFM provided a more accurate measurement of feedwater flow independent of the installed feedwater venturies.
The final results from the calorimetric uncertainty analysis showed the uncertainty to be 1.01 %. Wl:ten this c:;alorimetric uncertainty of 1.01 % is added to the maximum power level recorded (100.41%), the resulting value is within the Palisades Design Basis value of 102%. It is, therefore, concluded by this analysis that actual reactor power did not exceed the design basis value throughout this event.
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i The results of the more accurate UFM revealed that actual power was 2.2% less than indicated power based on the feedwater venturies. The conservative bias associated with the venturies is due primarily to a conservative initial venturi calibration and to venturi fouling. The UFM device is considered to be more accurate than the venturies due to rigorous testing by the vendor and the device's independence from fouling.
Using the ultrasonic flow results, the maximum power level achieved during the event was determined to be 98.2%. It has, therefore, been concluded that Palisades' actual reactor power did not exceed 100% licensed power throughout the event.
REASON FOR THE VIOLATION The root cause for the event was that the procedural guidance for the operators regarding compliance with licensed steady-state reactor core power levels was not sufficiently conservative.
CORRECTIVE STEPS TAKEN AND RESULTS ACHIEVED The following corrective actions were accomplished:
Operating procedures have been revised to better define *isteady state" and prohibit operation at a steady state power level greater than the license limit.
The calorimetric uncertainty analysis was reviewed to verify that it reflected known uncertainties. The analysis revealed that Palisades remained within the established design basis at all times.
A flow test using UFM was performed on May 21-22, 1996. The results of the flow measurement revealed that the installed flow venturies have a conservative bias. This resulted in the indicated reactor power reading higher than the actual power. The measurement results indicated that 100% power was not exceeded throughout the event.
CORRECTIVE STEPS TAKEN TO AVOID FURTHER VIOLATIONS No additional actions are required.
DATE WHEN FULL COMPLIANCE WILL BE ACHIEVED Full compliance was achieved on March 11, 1996, when the appropriate procedures were revised.
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