ML20086Q829
| ML20086Q829 | |
| Person / Time | |
|---|---|
| Site: | Waterford  |
| Issue date: | 07/26/1995 |
| From: | Barkhurst R ENTERGY OPERATIONS, INC. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20086Q831 | List: |
| References | |
| W3F1-95-0088, W3F1-95-88, NUDOCS 9507280207 | |
| Download: ML20086Q829 (9) | |
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- I Td 504 739 6661 Ross P. Barkhurst ut fwma Weavu V/mJ c19 W3F1-95-0088 A4.05 PR July 26, 1995 U.S. Nuclear Regulatory Commission Attn:
Document Control Desk Washington, D.C. 20555
Subject:
Waterford 3 SES Docket No. 50-382 License No. NPF-38 Technical Specification Change Request NPF-38-169 Gentlemen: The attached description and safety analysis supports a change to the Waterford 3 Technical Specifications (TS). The proposed change modifies specification 3.8.1.1 and associated bases by extending the Emergency i Diesel Generator allowed outage time (A0T) from 72 hours to seven days, j with an additional once-per-refueling cycle 10 day A0T for maintenance purposes. This amendment is a collaborative effort of participating Combustion Engineering Owners Group members based on 'an integrated review and assessment of plant operations, deterministic and design ~ basis considerations and plant risk. Joint Application Report CE NPSD-996, referenced herein in support of this change, has been submitted to.the staff for review and approval under separate letter CE0G-95-344 dated July 10, 1995. -{ The proposed change has been evaluated in accordance with 10CFR50.91(a)(1) using criteria in 10CFR50.92(c) and it has been determined that the i proposed change involves no significant hazards considerations. The Plant Operations Review and Safety Review Committees have reviewed and accepted i the proposed change based on the evaluation mentioned above. l b 2S00.e n \\h 9507280207 950726 PDR ADOCK 05000382 \\ l P PDR )
" Technical Specification Change Request NPF-38-169 W3F1-95-0088 Page 2 July 26, 1995 Waterford 3 requests that the implementation date for this change be within 60 days of NRC issuance of the amendment to allow for distribution and procedural revisions necessary to implement this change. Although this request is neither exigent nor emergency, your prompt review is requested. Should you have any questions or comments concerning this request, please contact Paul Caropino at (504)739-6692. Very truly yours, 53 R.P. Barkhurst Vice President, Operations Waterford 3 RPB/PLC/ssf
Attachment:
Affidavit NPF-38-169 cc: L.J. Callan, NRC Region IV C.P. Patel, NRC-NRR R.B. McGehee N.S. Reynolds NRC Resident Inspectors Office Administrator Radiation Protection Division (State of Louisiana) American Nuclear Insurers
UNITED STATES OF AMERICA- ~ NUCLEAR REGULATORY COMMISSION '~ p 'In'the matter of. ) ) Entergy Operat' ions, Incorporated ) Docket No. 50-382 Waterford 3 Steam Electric Station ) AFFIDAVIT R.P. Barkhurst, being duly sworn, hereby deposes and says that' he is Vice President Operations - Waterford 3 of Entergy Operations, Incorporated that he is duly authorized to sign and file with the Nuclear Regulatory Commission the attached Technical Specification Change Request NPF-38-169; that-he is familiar with the content thereof; and that the matters set forth therein are true and correct to the best of his knowledge, information and belief. N R.P. Barkhurst Vice President Operations - Waterford 3 STATE OF LOUISIANA ) ) ss PARISH OF ST. CHARLES ) -Subscribed and sworn to before me, a Notar:r Public in and for'the Parish and State above named this 2@" day of Vowf , 1995. _ SL. E IT% Notary Public My Commission expires N'M ' % b' ..,- e f %
p DESCRIPTION AND SAFETY AWALYSIS OF PROPOSED CHANGE NPF-38-169 l The allowed outage time (A0T) for an inoperable emergency diesel generator (EDG) is being extended from the existing limit of 72 hours to seven days (168 hours). Also, a once-per-refueling cycle 10' day A0T is being added for the purposes of either corrective or preventative maintenance. Existina Specification i See Attachment A P Proposed SDeCifiCation i See Attachment B Backaround i Waterford 3 is equipped with two seismically qualified, class 1E, diesel engine driven generators which supply backup electrical power to the 4160 volt i (V) vital ' AC busses. Each engine is designed to automatically start and tie-on to its respective 4160V engineered safety features (ESF) bus in the event of a bus undervoltage condition on either the 4160V bus or its associated 480V motor control center. The EDGs also receive an auto start command on a safety l injection actuation signal, but will not load unless a bus undervoltage condition exists. Each EDG is designed to start automatically upon receipt of a start signal, attain rated speed and voltage within 10 seconds,'and sequentially accept ESF loads. The EDG is sized to supply reliable power to all safety-related loads in its respectiva division, as well as specific nonsafety related loads. The EDGs have a continuous load rating of 4400 kilowatts (kW) 'with a 2-hour rating of 4840 kW. 1 The EDGs are designed for manual operation from either the local control' panel-or the control room operating panel. This provision allows operation for surveillance testing and manual start and load operations as well as local operations in an event which renders the control room inaccessible. The EDGs are described in chapter 8.3.1 of the Waterford 3 Final Safety . Analysis Report. 1 i
.- Description The current Waterford 3 technical specification (TS) 3.8.1.1 requires that if
- an EDG is declared inoperable for any reason, the EDG be restored to an operable status within 72 hours or place the plant in at least hot standby within the following six hours and in cold shutdown within the following 30 hours. The proposed TS amendment would allow up to seven days to restore operability to an EDG.
It also makes provisions for a once-per-refueling cycle allowance for a ten day A0T on a single EDG for the purpose of j performing corrective or preventative maintenance necessary to restore j operability or improve reliability. The desire to perform select corrective and preventative maintenance on-line is based on a number of expected enhancements to the maintenance process. Some examples are: Allow for increased flexibility in the scheduling and performance of ) preventative maintenance. Reduction in the number of individual entries into limiting conditions for operation action statements by providing sufficient time to perform related maintenance tasks within a single entry. l Allow better control of resource allocation. During outage maintenance windows, plant personnel and resources are spread across a large number and wide variety of maintenance tasks. Allowing on-line maintenance gives the plant the flexibility to focus more quality resources on any required or elected EDG maintenance. Avert unplanned plant shutdown and minimize the potential for notice of enforcement discretion requests. Risks incurred by unexpected plant shutdowns can be comparable to and often exceed those associated with continued power operation. Improve EDG availability during shutdown modes. The Combustion Engineering Owners Group (CE0G) " Joint Applications Report for Emergency Diesel Generators A0T Extension," CE NPSD-996, has explored and evaluated the various risk contributors associated with the proposed A0T extensions. This evaluation includes a consideration of the risk associated 1 with "at power", " transition" and " shutdown" operations. i 1 w
? The evaluation of "at power risk" change resulting from the extended EDG A0T I was performed using plant specific information from each of the participating 1 CEOG members. The results for Waterford 3 show that the proposed A0T changes could increase the average core damage frequency (CDF) by approximately 14%. \\ The CE0G Report identifies the "at power risk" increase in CDF at Waterford 3 as being higher than the other plants in the study. This increased impact is primarily due to conservative treatment of the Station Black Out event within Waterford 3's Individual Plant Evaluation (IPE). Specifically, the Waterford 3 IPE assumes that all EDG failures occur at the time of loss of offsite power (i.e. all EDG failures are conservatively assumed to be start failures). Even with this conservative modeling approach, Waterford 3 has a relatively low 4 plant baseline CDF (1.54 x 10 per year). By using a more realistic approach to the treatment of EDG failure, the "at power risk" increase should generally be comparable to those associated with the CE groups as a whole. Transition risk represents the risk associated with reducing power and going to hot or cold shutdown. This risk is of interest in understanding the tradeoff between shutting down the plant and restoring EDG operability while the plant continues operation. The results of this risk assessment indicate that performing a seven day EDG corrective maintenance activity "at power" would be risk beneficial. Shutdown risk is an assessment of the risk associated with removing an EDG from service while the plant is in a shutdown mode of operation. The results of this risk assessment indicate that performing corrective or preventative maintenance at power would be risk neutral when compared with early outage maintenance and result in a slight increase in risk when compared with late outage maintenance. Performing preventative maintenance at power will however provide greater EDG reliability upon entering shutdown modes than if maintenance had been performed at the end of a refueling outage. The CE0G report also performed an assessment of the proposed change on large early release scenarios. The assessment of the three classes of events considered for these scenarios concluded that increased unavailability of one EDG will result in a negligible impact on the large early release probability for Waterford 3.
l . The CE0G report concludes that an EDG A0T extension to seven days with a once i per cycle ten day A0T may potentially result in a small increase in the "at power" risk. However, when the full scope of plant risk is considered, the risks incurred by extending the A0T for either corrective or preventive maintenance will be substantially offset by plant benefits associated with avoiding unnecessary plant transitions, reducing risks during plant shutdown operations and improved EDG reliability upon entering shutdown. Safety Analysis The proposed change described above shall be deemed to involve a significant hazards consideration if there is a positive finding in any of the following areas: 1. Will operation of the facility in accordance with this proposed change involve a significant increase in the probability or consequences of an accident previously evaluated?
Response
No The emergency diesel generators (EDGs) are backup alternating current power sources designed to power essential safety systems in the event of a loss of offsite power. EDGs are not an accident initiator in any accident previously evaluated. Therefore, this change does not involve an increase in the probability of an accident previously evaluated. The EDGs provide backup power to components that mitigate the consequences of accidents. The proposed changes to allowed outage times (A0Ts) do not affect any of the assumptions used in deterministic safety analysis. In order to fully evaluate the EDG A0T extension, probabilistic safety 1 analysis methods were utilized. The results of these analyses indicate no significant increase in the consequences of an accident previously evaluated. These analyses are detailed in CE NPSD-996, Combustion Engineering Owners Group " Joint Applications Report for Emergency Diesel Generators A0T Extension." Therefore, the proposed change will not involve a significant increase in the probability or consequences of any accident previously evaluated. u
- 2. '
Will operation of the facility in accordance with this proposed change create the possibility of a new or different type of accident from any accident previously evaluated? L
Response
'No. This proposed change does not alter the design, configuration, or method of operation of the plant. Therefore, the proposed change will not create the possibility of a new or different kind of accident from any accident previously evaluated. 3. Will operation of the facility in accordance with this proposed change involve a significant reduction in a margin of safety?
Response
No The proposed changes do not affect the technical specification limiting conditions for operation or their bases which support the deterministic i analyses used to establish the margin of safety. Evaluations used to support the requested technical specification changes have been demonstrated to be either risk neutral or risk beneficial. These 3 evaluations are detailed in CE NPSD-996. Therefore, the proposed change will not involve a significant reduction in a margin of safety. Safety and Sianificant Hazards Determination Based on the above safety analysis, it is concluded that: (1) the proposed change does not constitute a significant hazards consideration as defined by 10CFR50.92; and (2) there is a reasonable assurance that the health and safety of the public will not be endangered by the proposed change; and (3) this i action will not result in a condition which significantly alters the impact of the station on the environment as described in the NRC final environmental statement. l 1
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