ML20210K430
| ML20210K430 | |
| Person / Time | |
|---|---|
| Site: | Pilgrim |
| Issue date: | 08/08/1997 |
| From: | Oheim H BOSTON EDISON CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20210K435 | List: |
| References | |
| BECO-LTR-2.97, BECO-LTR-2.97-0, TAC-M95277, NUDOCS 9708190256 | |
| Download: ML20210K430 (10) | |
Text
_ __ - - - -__ _ _-__ - ____ - --- - __-_____ - _---_____--_
Boston Edison Pdgrirn Nuclear Power Station Rocky Hdi Road Pivnouth. Massachusetts 02360 August 8, 1997 Henry V. Oheim BECo Ltr. #2.97-082 oeneral Manager - Technical Section U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555 Docket No. 50-293 License No. DPR-35 Supplement to Emergency Diesel Generator Allowed Outace Time Technical Specification Chance (TAC No. M95277)
Ref: 1.
Boston Edison Company Letter No.96-040, " Proposed Technical Specification Changes," dated April 25,1996.
2.
Boston Edison Company Letter No.96-080, " Response to Request For Additional information Regarding Emergency Diesel Generator Allowed Outage Time Technical Specification Change," dated September 5,1996.
Boston Edison Company (BECo) hereby provides additional information in support of the proposed Technical Specification change for the emergency diesel generator (EDG) allowed outage time (AOT) submitted on April 25,1996 (Ref.1).
- 1. Attachment A provides clarification on our previous responses to NRC questions (Ref. 2) and includes information regarding station blackout diesel generator (SBO-DG) reliability. This information responds to a NRC request in a telephone call on January 10,1997.
- 2. Attachment B includes revised Technical Specification pages 3/4.5-7, B3/4.5-6 and B3/4.5-7 requiring verification the SBO-DG is operable prior to voluntarily entering the Limiting Condition for Operation. The revised pages, which are submitted at NRC's request, do not affect our previous 10 CFR 50.92(c) finding of no significant hazards consideration determination included in our proposed Technical Specification change letter (Ref.1).
- 3. As requested by an NRC telephone call on December 2,1996, we performed additional testing of the SBO-DG to demonstrate its reliability. We completed 25 consecutive tests without a failure.
9708190256 970808 PDR ADOCK 05000293 h
- l Il P
PDR 4, a, O Q l 1.
M
Pcg32 4., in response to Licensee Event Report 97-004-00, " Loss of Preferred Offsite Power and Oil Spill Due to Main Transformer Fault While Shutdown", dated April 7,1957 ;BECo Letter No.
97-038A and NRC inspection Report 97-02, item No. 02), we have taken the following actions:
We have implemented procedural enhancements to provide guidance to operators regarding start-up and operation of the SBO-DG unloaded.
At the NRC inspection 97-02 exit meeting, we committed to complete a temporary modificatiun by September 30,1997, and a permanent modification by March 1998, to provide an altemate source of power to SBO-DG auxiliaries to ensure start-up and availability of_ SBO-DG during partial or degraded offsite power conditions. Instead of the temporary modification, a permanent plant design change, PDC 97-14, " Revised Power Supply for SBO Diesel Auxiliaries" is scheduled to be implemented-by September 30,1997.
In summary, the high reliability of EDGs and SBO-DG, and the procedural and auxiliary power supply improvements for SBO-DG fully support our technical bases for EDG AOT Technical Specification change request.
Commitments: This letter contains the following commitment.
We will revise PNPS procedure 1.5.21, " Work Control Scheduling Activities and Guidelines" and prepare training for the work control managers for use of a risk monitor for managing risk during planned on-line maintenance. This will be completed by December,1997.
Should you have any questions regarding this letter, please contact Walter Lobo at (508) 830-7940.
1 H. V. Oheim techspec/wgt/edgrai3 Attachment A: BECo Response to NRC Request for Additional Information Attachment B: Revised T.S. Pages 3/4.5-7,83/4.5-6 and B3/4.5-7 cc: Mr. Alan B. Wang, Project Manager Project Directorate 1-3 Office of Nuclear Reactor Regulation Mail Stop: OWF 1482 1 White Flint North 11555 Rockville Pike Rockville, MD 20852 U.S. Nuclear Regulatory Commission Region 1 475 Allendale Road King of Prussia, PA 19406
Pcge 3" Senior.Residint inspector Pilgrim Nuclear Power Station l
5Ir. Robert Hallisey Radiation Control Program -
Center for Communicable Diseases Mass. Dept. of Public Health 305 South Street -
Jamaica Plain, MA 02130 Mr. Peter LaPorte, Director Massachusetts Energy Management Agency _
400 Worcester Road P.O. Box 1496 i
Framingham, MA 01701 0313
- Attn: Mr. James Muckerheide
\\
BECo Letter No. 2.97.082 ATTACHMENT A BECO RESPONSE TO NRC ADDITIONAL INFORMATION REGARDING EMERGENCY DIESEL GENERATOR ALLOWED OUTAGE TIME TECHNICAL SPECIFICATION CHANGE
\\
Emeroency Di*sel Generator Allowed Out o,Tima Pilorim Nuclear Power Station A.
Rcferences 1
(1)
Request for Additional Information dated September 5,1996 (BECo Letter No.
l 96-080)
(2)
Proposed Technical Specification Change Request, dated April 25,1996 (BECo Letter No.96-040)
(3)
NRC Conference at Pilgrim Nuclear Power Station, November 13-14,1996 (4)
Response to Station Blackout Rule, dated April 17,1989 (BECo Letter No.89-057)
(5)
Response to SER on Station Blackout Rule, dated June 3,1991 (BECo Letter No.91-074)
(6) NRC SER on Station Blackout Rule, dated February 13,1991 (7). NRC Supplemental SER on Station Blackout Rule, dated January 15,1992 (8) NRC Final SER on Station Blackout Rule, dated March 5,1992 (9)
BECo response to NRC letter to NUMARC, dated August 31,1990 (BECo Letter No.90-106)
(10) BECo response to NRC Pilot Station Blackout Team Inspection 93-80, dated March 11,1994 (BECo Letter No.94-027)
(11) NRC Inspection Report 93-80, dated December 23,1993 (12) NRC Inspection Report 95-16, dated September 11,1995 (13) NRC License Amendment 170, NRC Letter dated February 10,1997 (14) LER 97-004-00," Loss of Preferred Offsite Power and Oil Spill Due to Main Transformer Fault While Shutdown", dated April 7,1997 (BECo Letter No. 97-038A)
(15) NRC Inspection Report 97-02, dated May 22,1997 8.
- Comparison of Maintenance Rule Performance Criteria. Actual Performance. and IPE Values The following table provides a comparison of maintenance rule performance criteria, actual equipment performance, and the 1992 individual plant examination (IPE) values for the emergency diesel generators (EDGs) and the station blackout diesel generator (SBO-DG).
Equipment PNPS Mainienance Actual Performance 1992 IPE Value Function Rule Performance Criteria Emergency Not More Than 1%
0.39 %
1.42%
Diesel (Based on a Five Year Generator (A or Moving Average B)
Through June 1997)
Unavailability SBO Diesel Not More Than 5%
1.84 %
1.20 %
Generator -
(Based on a Three Unavailability Year Moving Average Through June 1997)
Emergency Emergency Diesel 1 Failure in Past 100 4.80E 3 Diesel Generator Reliability Tests Failures / Demand Generator (A or Program 1 Failure in Past 50 B) Failure to Tests Start 0 Failure in Past 25 Tests A1
- Equ)pment PNPS M:inten:nco Actual Perf rm:nc3 1992 IPE Value Function Rule Performance Criteria Emergency Emergency Diesel 1 Failure in the Past 3.3E-4 Diesel Generator Reliability 100 tests Failures / Hour Generator (A or Program 1 Failure in Past 50 B) Failure to Tests Run 0 Failure in Past 25 Tests SBO Diesel Not More Than 1 1 Maintenance Rule 4.80E-3 Generator Functional Failure During Functional Failure Failures / Demand Failure to Start Two Year Moving Time During Latest Two Period Year Period Through June 1997' (Represents 20 Tests)
SBO Diesel See above.
O Run Failures During 3.3E-4 Generator Latest Two Year Failures / Hour Failure to Run Period Through June 1997 Note 1: Note that the SBO Maintenance Rule functional failure (blown out fuse) listed in item B table occurred and was corrected pn'or to the next SBO-DG surveillance test.
The EDG performance is administratively monitored per the maintenance rule program. As shown by the table above, the performance of the EDGs is better than the criteria in the maintenance rule program and consistent with that assumed by the IPE.
The SBO-DG performance is also administratively monitored per the maintenance rule program. Performance cannot degrade below the rule limits without implementation of corrective actions to restore performance to acceptable maintenance rule program criteria.
The SBO-DG currently meets the maintenance rule program performance criteria but has a higher unavailability level than assumed by the 1992 IPE. Therefore, a sensitivity study was performed, using our updated PRA model, assuming the SBO-DG performed at the maximum unavailability and failure rate permitted by the maintenance rule program. This worse case assumption resulted in a small increase in the plant baseline core damage-frequency but had no adverse impact on our risk evaluation for the acceptability of a 14 day EDG allowed outage time. The current SBO-DG performance, even though below that assumed in the IPE, is inconsequential to our conclusions regarding the acceptability of a 14 day EDG Technical Specification Limiting Condition of Operation for the allowed outage time.
C.
AC and Support Eauipment included Within the Scope of the PNPS Maintenance Rule Procram The following AC and support equipment are included in the scope of the Maintenance Rule ( 10 CFR 50. 65):
. 345 Kv breakers and lines Start-up transformer Emergency diesel generators and support equipment (including fuel delivery)
Emergency service portion of the auxiliary power distribution system 23 KV line Shutdown transformer 4160 Volt buses A2
e 480 Volt bus::s All AC breakers listed in FSAR Table 8.4-3.
Equipment that supports the performance of the risk significant power transmission and distribution functions including the transmission and distribution of electrical power to the safety-related buses, bus protection, power selection / modification, and structural support.
D.
Full Load Rejection Test followina Postulated Replacement of EDG Govemor As further clarification of our response to NRC question 3.a and b (Reference 2), a full load rejection test will not be performed on-line. Major components, such as a govemor, are replaced only when necessary, with a detailed work plan and appropriate post-work test.
1 E.
SBO-DG Batterv Information The 125V DC control power for the SBO-DG is normally supplied from the battery charger within bus A8. The normal supply to the charger is from MCC B40. On a loss of off-site power, the batteries within bus A8 will supply 125V DC to the control and protection system for bus A8. When the station blackout diesel is started, it will then supply power to the battery charger via MCC B40.
The battery charger is rated at 12 amps and the load on the charger is approximately 1 amp during normal operation. The battery consists of 92 cells rated at 1.4V DC per cell (129V DC bank voltage).
During SBO-DG operation, the charger / battery will supply and maintain the necessary DC loads.
F.
Procedural and Eauipment Modifications Following the event described in LER 97-004-00, " Loss of Preferred Offsite Power and Oil Spill Due to Main Transformer Fault While Shutdown" (Ref.14 and 15), which included a failure of the SBO-DG to start, we have taken the following actions to improve the availability of SBO-DG:
- 1. We have revised plant procedure 2.2.146 " Station Blackout Diesel Generator" to provide guidance to operators when to start and how to run the SBO-DG unloaded.
- 2. At the NRC inspection 97-02 exit meeting, we committed to complete a te.nporary modification by September 30,1997, and a permanent modification by March 1998, to provide an altemate source of power to SBO-DG auxiliaries to ensure start-up and availability of SBO-DG during partial or degraded offsite power conditions. Instead of the temporary modification, a permanent plant design change, PDC 97-14, " Revised Power Supp!y for SBO Diesel Auxiliaries" is scheduled to be implemented by September 30,1997. Currently, power to SBO-DG auxiliaries is fed from 480V load center B4 to MCC B40. The modification changes the power supply to MCC B40 from load center 84 to 480V distribution panel P45. On a loss of off-site power, panel P45 will be powered from the 400KW security diesel generator.
G.
Plant Reliability Analysis We will revise PNPS procedure, 1.5.21 " Work Control Scheduling Activities and Guidelines" and conduct training for the work control managers by the end of 1997, to introduce the use of a risk monitor into the planning for each work week. This will enhance the risk management awareness when conducting on-line maintenance.
A3 i
H.
Station Blackout Diesel Generator Reliability Prooram
===1.
Background===
in a telephone call on January 10,1997, the NRC requested information on the station blackout diesel generator reliability program within the scope of the commitments made in item A.3 of reference 4 and item A.6.(b) of reference 5. We are providing the following information clarifying the SBO-DG reliability program.
2.
SBO-DG Reliability Program Pilgrim Nuclear Power Station designated the SBO-DG as the alternate AC power source, meeting the 10CFR50.2 and 10CFR50.63(c)(2) requirements of having the capability to power the shutdown buses within 10 minutes of the onset of a station blackout event. A coping analysis was not required as specified in 10CFR50.63(c)(2) since our method of compliance with the SBO Rule used an alternate AC source (SBO-DG). BECo identified an EDG target reliability of 0.95 (reference 4) to calculate the station blackout duration in accordance with the methodology of Regulatory Guide 1.55. The NRC approved BECo's implementation of the SBO Rule in a series of NRC Safety Evaluation Reports (references 6,7, and 8).
In response to the NRC initial SER (reference 6, page 2, item #f and item 2.2.2), BECo provided information on the alternate AC source (SBO-DG) reliability in item A.6.(b) of reference 5 stating that
- A target reliability of 0.95 will be established and a reliability program implemented post-RFO #9 after completion of the 10 minute energization modification" BECo established a target reliability goal of 0.95 during RFO #9 following the completion of the 10 minute energization modification. The SBO DG reliability program was written and implemented post RFO #9, progressively collecting data to demonstrate the target reliability goal of 0.95. Accordingly, BECo met the intent and scope of the commitment specified in reference 5. The EDG target reliability was later revised to 0.975 (reference 9), when we endorsed NUMARC 87-00 guidance to estabiish the EDG reliability program.
BECo implemented the SBO-DG reliability goat using the guidance of Generic Letter 84-15 that states excessive diesel generator testing is not recommended. Implementation of the reliability goal is documented in NRC inspection reports (references 11 and 12). Even though we collected less than the normally required data towards the reliability goal, the NRC closed unresolved item 93-80-02 based upon BECo's strength in effectively addressing the reliability issues, progressive manner of collecting the data, and the NSAC-108 methodology. NSAC-108 concluded that plants having a small number of demands on the SBO-DG should not be judged unacceptable solely on the basis that the SBO-DG has had few demands within a year (reference 10).
Accordingly, BECo considered the SBO-DG reliability issue resolved and Pilgrim Station in compliance with the SBO Rule.
3.
Additional SBO-DG Start-Up and Reliability Data As a part of its review of the proposed license amendment, the NRC requested that BECo conduct additional testing of the SBO-DG to demonstrate its reliability. In compliance with the request, we performed accelerated surveillance tests in 1997 with no failures.
A4
From October 17,1994 through December 1996, we complatId twelva successful tssts of
- ths SBO-DG Wa performid thirtnn tdditionil tssts of th3 SBO-DG to drmonstrate its reliability; We completed all 25 consecutive runs without a failure by June 1997.
l.
Proposed Technical Specification Paoes Attachment B to this letter contains proposed Technical Specification pages to incorporate the SBO-DG into Pilgrim Technical Specifications. These supersede the pages submitted in reference 1 and include changn approved by the NRC in reference 13.
l Page 3/4.5-7, submitted in reference 1, contained an error.
Surveillance 4.5.F.1 references surveillance 4.9.A.1.b.2.
The correct surveillance is 4.9.A.1.a which is the routine monthly test of the diesel. This error has been corrected on the attached page.
Reference 1 included proposed SBO-DG surveillance 4.5.2: "once every 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> verify correct SBO-DG breaker alignment to the emergency bus associated with the inoperable EDG".
The SBO-DG is manually started and feeds one emergency bus through the same breakers used for the shutdown transformer. When the SBO-DG is requiled to feed a bus, the breaker to one cmergency bus (A501 or A601) is manually opened and pulled-to-lock, and the SBO-DG is started.
Aligning breakers for SBO-DG operation isolates one emergency bus from the shutdown transformer. This is undesirable because the shutdown transformer is capable of automatically supplying power to either emergency bus; whereas, the SBO-DG requires operator action and is capable of supplying only one emergency bus with 2000KW.
Therefore, Surveillance 4.5.2 has been modified to require " once every 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />, verify normal breaker configuration". Modifying the surveillance in this manner assures the breakers are configured so the SBO-DG is capable of being connected to a safety bus without interrupting the normal function of the shutdown transformer.
a BECo Letter No. 2.97.082 ATTACHMENT B REVISED TS PAGES 3/4.5-7, B3/4.5-6 and B3/4.5-7
_.