2CAN099604, Responds to RAI Re LPSI & SIT Allowed Outage Time Extensions to Facilitate Review of Tech Spec Change Request
| ML20128G221 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 09/30/1996 |
| From: | Mims D ENTERGY OPERATIONS, INC. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 2CAN099604, 2CAN99604, NUDOCS 9610080396 | |
| Download: ML20128G221 (5) | |
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-:-:- ENTERGY cntergy opera: tons. ine.
ma a m htenM'c AR /2301 ic! 501853 5000 2
September 30,1996 2CAN099604 e
U. S. Nuclear Regulatory Commission Document Control Desk Mail Station PI-137 Washington, DC 20555
Subject:
Arkansas Nuclear One - Unit 2 Docket No. 50-368 License No. NPF-6 Response To Request For Additional Information Concerning LPSI Ar,d SIT Allowed Outage Time Extensions Gentlemen:
By letters dated May 19,1996 (2CAN059502 and 2CAN059503), Entergy Operations requested technical specification changes concerning the allowed outage time for the low pressure safety injection system and the safety injection tanks. In subsequent discussions with the NRC staff, additional information was requested to facilitate the review of the technical specification change requests. Attached are responses to the requested information. If you have further questions, please call me.
Very truly yours, Dwight C. Mims Director, Nuclear Safety DCM/gra Attachments
, /DDl ' ,
W0079 9610080396 960930 PDR ADOCK 05000369 P PDR
U. S. NRC
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September 30,1996 2CAN099604 Page 2 cc: Mr. Leonard J. Callan Regional Administrator U. S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011-8064 NRC Senior Resident Inspector Arkansas Nuclear One P.O. Box 310 London, AR 72847 Mr. George Kalman NRR Project Manager Region IV/ANO-1 & 2 U. S. Nuclear Regulatory Commission NRR Mail Stop 13-H-3 >
One White Flint North 11555 Rockville Pike Rockville, MD 20852 l
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Attachment to
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l Additional RAI for the ANO-2 Application for AOT Extension (LPSI & SIT) 4 j Ref; (1) February 27,1996 letter from Dwight C. Mims, Director of Safety, ENTERGY, j " Response to NRC Questions On ANO-2 Application ..." to NRC; (2) June 14,1996 i letter from D. Pilmer, Chairman, C-E Owners Group, "CEOG Response to Request ..." to l NRC Question: This question addresses the adequacy of the future " Tier 3" implementation at
- that the group members will use one or more of the following tools (Page 4-2, Response
- i. to Question 4): (1)PSA derived matrices or (2) a Risk Calculator. In your response to a different set of RAls sent to ENTERGY (reference 1, page 4, Response to Question 4),
i you list areas you will consider prior to the removal of any important piece of equipment
- from service. NRC's interpretation of your response is that you will use the "PSA derived
- matrices" tool. Clarifications on this point would be appreciated. Specifically
- (1) When l you state that " risk is assessed for each and every work activity scheduled," is the risk i assessed using the PRA model described in your response to Question 1 (reference 1)? (2)
! When you perform your " Aggregate assessments" each day (see bullet 5 of response to ;
i question 4, page 4), do you do so using the PRA model described in your response to
- Question 17 (3) How is the " system priority chart" and the " risk assessment form" related j to the PRA configuration assessment? (4) Does ANO-2 have a " risk calculator," and if so,
, how do you assure that it has up-to-date information in it for accurate configuration control management?
i 4 The specific RAI questions and responses are shown below.
OUESTION 1 4
l When you state that " Risk is assessed for each and every work activity scheduled," is the '
risk assessed using the PRA model described in your response to Question 1 (reference 1)?
RESPONSE
The operations liaison performs an aggregate risk assessment for each work activity. The aggregate risk assessment considers the plant impact of the work activity not only from ;
it's singular effects, but also from an aggregate view considering other existing work i activities, related component / system deficiencies, and various modes of operation. 'Ihe aggregate assessments portion of the overall assessment includes the following items for :
consideration:
Attachm:nt to 2CAN099604 Page 2 of 3 e In aggregate, does the newly identified work activity suggest an increased significance or priority?
e How will the work activity weigh in aggregate should present plant operating status change?.
- From an aggregate view, has an increased operator burden or a new operator workaround emanated?
e Will the deficiency be considered an Operation's concern given the aggregate assessment?
e How is operation in EOP/AOP mode impacted from the aggregate view?
e Should previously identified work activities be upgraded in significance or priority?
For safety significant components, the aggregate assessment will include review of the PSA risk matrix. The PSA risk matrix is derived from the PRA model described in the response to Question 1 ofreference 1. The risk matrix provides the Operations planning and scheduling liaison with a tool to evaluate plant risk configurations based on multiple trains / components being out of service concurrently. The risk matrix identifies minimal, moderate, high and unacceptable risk configurations.
OUESTION 2 When you perform your " Aggregate assessments" each day (see bullet 5 of response to question 4, page 4), do you do so using the PRA model described in your response to Question 17
RESPONSE
The assessment of risk for each work activity is accomplished using the aggregate assessment described in the response to Question 1.
OUESTION 3 How is the " system priority chart" and the " risk assessment form" related to the PRA configuration assessment?
RESPONSE
System priority chart - This chart lists the risk significant systems and prioritizes them according to their respective Core Damage Frequency (CDF). The CDF's from which the system priorities are derived are from a baseline PRA model which is periodically updated to reflect modifications to equipment and/or operating practices.
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- Attachment to 2CAN099604 Page 3 of 3 l Risk assessment form - In order to help determine the impact of a work activity on plant I operations, the operations liaison completes a risk assessment form for any activity that could result in the following:
l e Reactor trip or plant transient e Unexpected loss or degradation of a major con.rol system
. Safety System unavailable for >50% of LCO e Challenge Unit availability l The current philosophy is to evaluate risk, gain, and consequences of each task that meets the above criteria. The ' risk assessment form' provides a set of aualitative questions that ;
the responsible maintenance person must answer in order to allow a aualitative evaluation 1 of the risk, gain and consequences of work activities. The risk assessment form is not
- intended to be used to perform a quantitative type of assessment. As such the risk assessment form is not related to any PRA configuration assessment. NOTE
- This form is only completed for tasks which meet the listed criteria. The form is not completed for each work activity.
OUESTION 4 Does ANO-2 have a " risk calculator" and if so, how do you assure that it has up-to-date information in it for accurate configuration control management?
RESPONSE
ANO-2 does not currently have a " risk calculator". However, as stated in the response to Question 13 of Reference 1, Entergy plans to implement on-line safety monitors (i.e. risk calculators) at both ANO units. It is the intent of ANO to update the on-line safety monitors periodically to reflect plant modifications or changes in plant operating practices.