ML20133C786
| ML20133C786 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 01/07/1997 |
| From: | Eaton R NRC (Affiliation Not Assigned) |
| To: | Roche M GENERAL PUBLIC UTILITIES CORP. |
| References | |
| TAC-M94856, NUDOCS 9701080093 | |
| Download: ML20133C786 (7) | |
Text
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January 7, 1997 I
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Mr. Michael /B. Roche Vice President and Director GPU Nuclear Corporation Oyster Creek Nuclear Generating Station Poss Office Box 388 Forked River, New Jersey 08731
SUBJECT:
OYSTER CREEK - REQUEST FOR ADDITIONAL INFORMATION REGARDING EMERGENCY DIESEL GENERATOR ALLOWED OUTAGE EXTENSION REQUEST (TAC N0.
M94856)
Dear Mr. Roche:
The U.S. Nuclear Regulatory Commission (NRC) staff has reviewed your application of February 22, 1996, regarding the subject change to your technical specifications and has determined that additional information is required to complete our review.
The information required for the review of the probabilistic safety assessment portion is contained in the enclosure.
In order to meet our current schedule the staff requests that you respond within 60 days of receipt of this letter.
Sincerely, (Original Signed By)
Ronald B. Eaton, Senior Project Manager Project Directorate I-2 Division of Reactor Projects I/II Office of Nuclear Reactor Regulation Docket No. 50-219
Enclosure:
As stated i
cc w/ enclosure:
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M. Roche Oyster Creek Nuclear GPU Nuclear Corporatiori Generating Station Cc:
Ernest L. Blake, Jr., Esquire Shaw, Pittman, Potts & Trowbridge 2300 N Street, NW Washington, DC 20037 Regional Administrator, Region I U.S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406-1415 BWR Licensing Manager GPU Nuclear Corporation; 1 Upper Pond Road l
Parsippany, NJ 07054 i
Mayor Lacey Township 818 West Lacey Road Forked River, NJ 08731 Licensing Manager Oyster Creek Nuclear Generating Station
. Mail Stop: Site Emergency Bldg.
P.O. Box 388 Forked River, NJ 08731 Resident Inspector c/o U.S. Nuclear Regulatory Commission P.O. Box 445 Forked River, NJ 08731 Kent Tosch, Chief New Jersey Department of Environmental Protection Bureau of Nuclear Engineering CN 415 Trenton, NJ 08625 December 1996
Reauest for Additional Information i
on the Oyster Creek Anolication for Technical Specifications Chance i
on EDG Allowed Outane Time (A0T)
BACKGROUse0 In reviewing risk-based TS modifications and associated amendments, the NRC i
staff will use an approach that focuses on three areas. These areas include:
The validity of the PSA and associated insights regarding the TS change.
1.
2.
Identification of risk-significant plant configurations prior to A0T entry.
3.
Plant configuration and centrol based on PSA insights.
The staff will evaluate:
- 1) the appropriateness of licensee activities in each area, (2) the applicability of the licensee's probabilistic risk assessment (PRA) methodology to support the proposed TS change, and (3) the impact of the proposed TS change on plant operational risk and containment performance, and the significance of licensee proposed compensatory measures.
The staff's conclusion will be based upon licensee commitment to compensatory measures, in conjunction with PRA insights and findings.
MFINITIONS (1) Change in average CDF (am(CDF)):
m(CDF) average CDF (per year) m (CDF) -
The conditional m(CDF) with the proposed A0T in place 2
m (CDF) -
The m(CDF) with the current A0T in place i
Therefore, am(CDF) - m (CDF) - m,(CDF) g (2) Change in instantaneous CDF (oCDF ):
i CDF (2) -
The conditional CDF when the plant is in the proposed i
A0T CDF(l)
The base CDF (unconditional) 1-modelled A0T configuration with an EDG unavailable Therefore, ACDF, - CDF (2) - CDF(1) i ATTAcimENT
(3) Change in average large early release frequency (am(LERF))
m(LERF) - average LERF (per year) m (LERF) - conditional m(LERF) with proposed A0T in place a
i e,(LERF) - m(LERF) with current A0T in place Therefore, am(LERF) - m,(LERF) - m (LERF) 3 (4) Change in instantaneous large early release frequency (RERF,)
LERF,(2) = the conditional LERF when the plant is in proposed A0T LERF(1) - the base LERF (unconditional) 1 - modelled configuration with an EDG unavailable Therefore, EERF, = LERF,(2) - LERF(l)
REQUESTED QtIEST10RfS Please respond to the questions generated below. Where sensitivity studies are requested, provide the change in average SB0/ LOOP induced CDF, instantaneous CDF, average LERF, and instantaneous LERF as a result of the proposed A0T extension.
Break down these contributions into percentages of LOOP and SB0 contribution.
Provide the initial and final values for the change in instantaneous and average LERF and CDF, as well as the change.
Area 1 1.
With respect to your explanation to question #4 in your June 13, 1996, response to a RAI, the basic OCPRA which you used for part of your analysis is your IPE.- Is this correct?
If this is correct, have any changes been made to the IPE since you submitted it to NRC? If so, please discuss any major differences, specifically with respect to LOOP and SB0 sequences.
2.
If your IPE has been modified to construct the current version of OCPRA which you are using to support this requested EDG A0T gr if OCPRA is not related to your'IPE, please answer the following questions:
Discuss how the current version of OCPRA reflects the as-built, as-operated plant. What reviews were performed to ensure that OCPRA reflects current conditions? What reviews were performed to ensure the OCPRA contains the necessary fine structure (resolution) to evaluate the ATTACHMERY
t proposed TS requirements? Explain any changes that were made to the PRA due to any such review. Discuss the adequacy of the completeness of the PRA, i.e. the inclusion of all significant systems, structures, and components.
Please describe the peer reviews performed on the current OCPRA.
Indicate which reviews were performed in-house versus those performed by outside consultants. Summarize the reviewers' overall conclusions and insights.
From this point forward in the questions, OCPRA refers to the version used in
~
support of the requested EDG A0T extension.
l 3.
Provide the minimal cutset truncation cutoff used to quantify the plant CCF changes.
In particular, indicate what efforts were made to avoid underestimation of the risk due to truncation.
4.
Discus:, your treatment of EDG common cause failure in the PRA. Describe mechanisms which lead to common cause EDG failure to start and failure to run.
5.
Provide a discussion of the LOOP events that have occurred at your facility. Also, provide an explanation of the data used to calculate the LOOP initiating event frequency.
6.
Explain the impact of severe weather on SPO-induced core damage and how this was addressed in the OCPRA.
7.
Discuss recovery of AC power (from weather, switchyard, and grid) in OCPRA.
8.
Discuss the impact of the A0T on accident mitigation capability, e.g.,
the ability to vent, isolate, or flood containment. Discuss any potential increase in ISLOCA probability.
9.
Does the normally closed DC-powered MOV on the outlet piping of the isolation condenser fail shut on loss of DC power? Discuss the impact l
of battery lifetime on the cooling capability of the isolation condenser.
10.
Are the alternate AC (AAC) sources modelled in OCPRA?
If so, discuss how common cause failure was included in your modeling of AAC sources.
What is the reliability of each combustion gas turbine (CGT) which makes up the AAC7 Are the CGTs owned and run by Oyster Creek? If not, how does this affect the reliability? (For example, testing and maintenance, and testing and maintenance outages may not be determined by OC. Also will OC encounter any resistance to using the CGTs when needed? Please l
ATTACHMENT t
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i do not limit your response to the examples provided for guidance.)
If AAC is included in OCPRA, quantify SB0/CDF reduction (credit) taken in
+
OCPRA for AAC.
11.
What are the projected average corrective maintenance and preventive i
maintenance downtimes for EDGs used in your calculations? Explain how q
they are obtained. Discuss any sensitivity analyses that you have done on your CM and PM downtimes that affect the risk results in the previous 4
question. Discuss insights gleaned from the study?
12.
Is the failure of recirculation pump seal modeled in OCPRA? If not, provide sensitivity studies and corresponding results which depict the a
impact of a seal LOCA on the requested A0T extension. Perform those calculations for each of four definitions in Definitions Section.
Provide initial and final values of the variables in the Definitions 2
Section which lead to changes in the variables. Break down t
contributions into LOOP and SB0 as appropriate.
i 13.
For the calculations performed in question #4 in your June 13, 1996, response to a RAI, provide the LOOP contributions in addition to the SB0 contributions you have already given.
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14.
Quantify the impact of the extended EDG A0T on instantaneous and average i
LERF by calculating the change in LERF due to the proposed A0T.
Provide i
your definition of LERF, an explanation of this impact, and the initial I
and final values of LERF which are inputs into the change in
)
instantaneous and average LERF.
15.
Provide the values for the EDG reliability and availability used in OCPRA to calculate the SB0 CDF values. Discuss these values in 1
relationship to any goals associated with the implementation of the maintenance rule and in comparison to the actual past performance of the EDGs at the plant. Also, compare the values used in OCPRA to the target values committed to for SB0.
4 16.
Explain how EDG PM and subsequent on-line operability testing is treated i
in CDF calculations.
Area 2 1.
Given the A0T plant configuration, what does your PRA indicate are the most risk-significant systems? Please explain the results.
2.
For the systems you identified in the previous question, how would you ensure that no risk-significant plant equipment outage configurations would occur while the plant is subject to the LC0 proposed for modification? Are the bases for this assurance reflected in your procedures or TS?
ATTACMENT
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3.
Describe how PRA insights are used in the decision making process, specifically with respect to planning maintenance activities involving the EDGs.
4.
Have you thoroughly reviewed your TS to see if there are needs for any other changes to your TS or TS bases (in addition to the TS amendment items you are currently requesting) due to your request of EDG extension from 7 to 14 days? Please identify any TS changes made to ensure that the plant will not enter a known risk-significant plant configuration while in the A0T.
Area 3 i
1.
Are you capable of performing a "real-time" assessment of the overall
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impact on safety functions of related TS activities before conducting j
test and maintenance activities including removal of equipment from service? Please explain how this "real time" assessment tool, or other processes, will be used to ensure that risk-significant plant configurations will not be entered during the A0T.
2.
Explain how you are going to address the issue of configuration and control, consistent with the Maintenance Rule, i.e., to evaluate the impact of maintenance activities on plant configurations.
3.
Discuss how your configuration risk management program is reflected in TS.
4.
Within the framework of your proposed Configuration Risk Management Program, describe the qualifications of the personnel that will use or 1
report PRA results to upper management.
ATTACHMENT
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