ML20236L310
| ML20236L310 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 07/06/1998 |
| From: | Sorensen J NORTHERN STATES POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9807100308 | |
| Download: ML20236L310 (4) | |
Text
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Northern States Power Company Prairie Island Nuclear Generating Plant 1717 Wakonade Dr. E.
Welch, MN 55089 July 6,1998 10 CFR Part 2 U S Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555 l
PRAIRIE ISLAND NUCLEAR GENERATING STATION Docket Nos. 50-282 License Nos. DPR-42 50-306 DPR-60 Response to Notice of Violation (Office of Investigations Report No. 3-97-034)
Your letter of June 4,1998, which transmitted Office of Investigations Report No. 3-97-034 required a response to a Notice of Violation. Our response to the notice is contained in the attachment to this letter.
l In this response we have made no new NRC commitments. If you have any i
questions concerning this response, please contact Jack Leveille at 612-388-1121,
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x4662.
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Joel P. Sorensen Plant Manager l
Prairie Island Nuclear Generating Plant c:
Regional Administrator-lil, NRC NRR Project Manager, NRC
/0 Senior Resident inspector, NRC State of Minnesota, Attn: Kris Sanda J. E Silberg Attachment Response to Notice of Violation 9807100308 900706 PDR ADOCK 05000282 G
PDR l
t Attachment Response to Notice of Violation
.-Violation:.
10 CFR 50.9(a), " Completeness and Accuracy of information" requires, in part, that
- information provided to the Commission by a licensee be complete and accurate in all material respects.
Contrary to the above, Supplement 2, dated February 12,1997, to License Amendment Request dated January 29,1997, " Amendment of Cooling Water System Engineering Intake Design Basis," was not complete and accurate in all material respects.
- Specifically, the supplemental response stated, "During the first trial usage of the l procedure, the operators accomplished management of the cooling water demand, but not in the original 15 minute time frame." This statement was not oc. curate in that the 4
' operators never recognized that they were in an earthquake scenario and never l
o-entered the procedure being validated before the scenario was terminated. The submittal also inaccurately stated, "The procedure was then discussed with the crew to
' L determine how the procedure should be changed to improve performance. The
. changes were made and another trial usage was run. The 15 minute time frame was-3
~ achieved the second time." in actuality, the operators were specifically briefed on the J
event, the procedure to be used and the required actions. Despite this, the required valve closures were not begun until 16 minutes into the event. The statements were material because the basis for License Amendment 126/120, issued March 20,1997, was the operator's ability to'successfully recognize and respond to an earthquake prior to the cooling water pumps losing suction. Fortunately, NRC recognized the inaccuracy
. of the above statements and required extensive validation of the actual operator
- response time prior to approving the amendment.
This is a Severity Level IV violation (Supplement 1).
Reason for Violation:
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Background discussion --
L In November 1995, a test was performed on the Emergency intake Line for the
- Cooling Water System (the essential service water system at Prairie Island). The
_ purpose of the line is to provide water supply to the cooling water pumps if a i-L
4 Attachment Pag 32 seismic event would make the intake canal (normal supply of water) incapable of sup, plying the pumps. It had been questioned whether the emergency intake line could pass the flowrate assumed in the Updated Safety Analysis Report (USAR) for the plant. The test determined that the assumed flowrate could not be achieved. The emergency intake line was declared inoperable, entering a Technical Specification Limiting Condition for Operation Action Statement.
Options for restoring the system to operability were considered. One option being considered was that of isolating the non-essential cooling water loads in order to reduce the total load demand below the flowmte of one cooling water pump, then removing extra pumps from service; this would reduce the flowrate to a rate that could be passed through the Emergency intake Line.
A draft procedure was written to respond to an event in this way and, in order to test the procedure, a simulation was performed with a shift crew that was in training. The purposes of the simulation were to find the fiaws in the procedure in order to improve the procedure and to determine if the actions could be concluded in a short time frame. The operators were observed to be moving to management of the event, preparing to reduce cooling water flow, but not by entry into the intended procedure. Since the purpose of the simulation was to evaluate the procedure, the simulation was stopped. The statement in the submittal ("During the first trial usage of the procedure, the operators accomplished management of the cooling water demand, but not in the original 15 minute time frame.") was not intended to imply that the procedure worked or that the crew entered the procedure.
After stopping the first simulation, the procedure author and the crew worked through the scenario difficulties and the procedure was revised and the simulation re-run with the same crew. The procedure was then determined to be workable. The time of performance was of interest but was not the over-riding factor; the precise time the operators would have available to them was not yet known in November 1995. Fifteen minutes was thought to be a conservative estimate of the time available to reduce the totalload demand below the flow rate of one cooling water pump before the loss of water from the intake bay could starve the suction of the pumps. Calculations to determine the amount of time available were being developed in a parallel path. The primary purpose of the simulator runs was to ensure the procedure would result in the proper configuration of the cooling water system. In fact, during the second run, the elapsed time was not recorded by the engineer. It was concluded that the procedure was adequate to re-establish operability of the emergency intake line.
f Approximately one year later, the NRC issued a letter that concluded that the plant's reliance on operator action to establish operability of the cooling water system constituted an unreviewed safety question. A License Amendment Request was submitted January 29,1997 to address the seismic concerns of the intake canal and the operability requirements for the cooling water system with i
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Attachm:nt l
Page 3 l
the reduced flowrate capacity of the emergency intake line. Within a few days, l
discussions with the staffled to the February 12,1997 submittal addressed by l
'- the violation. At the time of this submittal, the time available to manage the cooling water loads was estimated by NSP to be 3.4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> (as indicated in the l
January 29,1997 submittal). The February 12,1997 submittal was intended to describe the purpose of the simulator runs as a procedure development tool, not as a formal validation of the procedure. That is why a different crew was not used for the second run (the use of the same crew is clearly stated in the submittal). The time given in the submittal for performance of the procedure was stated as "[t]he 15 minute time frame," meaning approximately 1b minutes. The engineer who oversaw the simulation and prepared the submittal to the NRC had not recorded the time nor remembered it exactly. When the questions from the NRC staff were being answered, it was thought that the pertinent issue was the method used to evaluate the procedure. The time elapsed was a secondary question since there were 3.4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> available (as thought at the time of the submittal) versus a "15 minute time frame."
The reason for the violation was the use of imprecise language in the submittal regarding elapsed time because less significance was placed on the actual elapsed time than on the method of evaluating the procedure.
l Corrective Actions Taken and Results Achieved:
A formal procedure validation was performed with several crews and accurate time estimates for performance were determined. This information was formally submitted to the NRC in Supplement 5 to the License Amendment Request dated January 29,1997.
4 Corrective Steps To Avoid Further Violations:
Since the submittalin question, an enhanced and documented review process for submittals to the NRC was instituted. It has been observed that this process has improved the quality of the information provided to the NRC.
Date When Full Compliance Will Be Achieved:
Full compliance has been achieved.
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