ML20236D804
| ML20236D804 | |
| Person / Time | |
|---|---|
| Site: | Byron, Braidwood, LaSalle, 05000000 |
| Issue date: | 07/22/1987 |
| From: | Ainger K COMMONWEALTH EDISON CO. |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| 3386K, GL-84-15, NUDOCS 8707310069 | |
| Download: ML20236D804 (6) | |
Text
{{#Wiki_filter:1 /O C:mm:nwzith Edison [; 2 )J Address Reply to: Post Office Box 767 One First National Plaza. Chicago, liknois g v (j Chicago, Illinois 60690 - 0767 July 22, 1987 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington DC 20555
Subject:
Byron Station Units 1 and 2 Braidwood Station Units 1 and 2 LaSalle County Station Units 1 and 2 Emergency Diesel Generator Surveillance Testing NRC Docket Nos. 50-454/455, 50-456/457, 50-373/374 Gentlemen: At the request of the NRC staff, Commonwealth Edison is providing information regarding surveillance testing of emergency diesel generators at Byron, Braidwood and LaSalle County Stations. This information request resulted from a telephone call between Commonwealth Edison and the NRC staff on July 20, 1987. The Technical Specifications for each station prescribe the periodic surveillance testing requirements for the emergency diesel generators. Technical Specification 4.8.1.1.2 (attached for each plant) contains the specific surveillance requirements. Time limits for diesel generator starting and loading must be verified as part of the surveillance test. About 10 seconds are allowed for a diesel generator to start and run. Sixty seconds are allowed for a diesel generator to accept its required electrical load. These time limits constitute the " fast start" issue that was addressed in NRC Generic Letter 84-15. Generic Letter 84-15 documented the NRC's position that fast start testing of emergency diesel generators should be reduced so that mechanical stress and wear on diesel engines is minimized. Our review of Generic Letter 84-15 indicates the rate at which a diesel generator is loaded is within the scope of the fast starting concern. Since the Standard Technical Specifica-tions required fast starts for all diesel generator surveillance testing, l Generic Letter 84-15 included an example of an acceptable change to Technical Specifications to accomplish a reduction in the number of fast starts. This proposed change added a footnote to the fast start time limits. G707310069 970722 ) DR ADOCK 05000373 PDR
USNRC July 22, 1987 This footnote was added to Byron, Braidwood and LaSalle County Technical Specification 4.8.1.1.2 so the fast start requirements could be avoided during the surveillance tests, except for once every six months. The footnote was included in the initial issuance of the Byron and Braidwood Technical Specifications. Since this footnote is referenced next to the 60 second time limit for loading the diesel generator, we have interpreted this footnote to allow the flexibility to gradually load the diesel generator. Without this interpretation, the footnote would not provide any benefit towards minimizing mechanical stress and wear on the Byron /Braidwood diesel engines. The footnote was added via an amendment to the LaSalle County Station Technical Specifications. Our amendment request of December 9, 1983, modified l January 11, 1984 (pertinent pages attached), indicated the intent to use the footnote such that "...the 13 second (or 60 seconds) time requirements will not apply for these starts." At Byron and Braidwood Stations, all engine starts are prelubricated using the prelube heaters and pumps. The design of the diesel engine is such that engine speed cannot be controlled during the starting period. The diesel generator will start and run at 600 rpm in 10 seconds. During the monthly surveillance test, the diesel generator loading procedure requires incremental load increases of 1000 kw over 3 to S minutes. During the six month surveillance, the diesel generator is loaded within 60 seconds. At LaSalle County Station, the monthly surveillance procedure requires a local start to control the idle speed of the diesel engine between 400 and 500 rpm. Three minutes later, the engine speed is gradually increased to 900 rpm. Then, the electrical load is applied without timing requirements. During the six month test, the diesel generator is started within 13 seconds, i synchronized to the bus, and then loaded within 60 seconds. I We believe our surveillance testing methods outlined above, which l follow from our interpretation of Technical Specification 4.8.1.1.2, are correct for the following reasons: 1. Commonwealth Edison believes application of a fast load to a diesel generator (within 60 seconds) will cause undue stress on the diesel engine and accelerate the rate of permanent wear on the mechanical parts of the engine. This can negatively affect the overall reliability of a diesel generator. 2. We believe our surveillance testing methods, which permit application of a gradual load to a diesel generator, are consistent with the direction in Generic Letter 84-15 regarding the fast start testing issue. 3. NRC I.E. Information Notice 85-32 "Recent Engine Failures of Emergency Diesel Generators" reinforces our interpretation of Technical Specification 4.8.1.1.2. It states "As part of Generic Letter 84-15, " Proposed Staff Actions to Improve and Maintain Diesel l Generator Reliability", the staff proposed measures to reduce the severity of engine starts and loading." I
USNRC July ?2, 1987 4. During recent inspections at Byron and Braidwood Stations in 1986 and 1987, the NRC staff reviewed the diesel generator monthly surveillance procedures and found them acceptable (reference inspection reports 50-454/87-002, 50-456/86-039, 50-456/87-014). It is our understanding that the NRC staff agrees with our diesel generator surveillance testing methods since it was stated during the telephone call on July 20, 1987 that we should continue testing diesel generators in the same manner. However, to avoid any future misunderstanding of Technical Specification 4.8.1.1.2, Commonwealth Edison agreed on the July 20, 1987 telephone call to submit applications for amendments to the Byron, Braidwood j and LaSalle County Station Technical Specifications to clarify the intent of 1 the footnote and its applicability to the time limits in Technical Specifica-tion 4.8.1.1.2. We expect to submit these amendment requests by July 28, 1987. I please direct any questions regarding this matter to this office. Very truly yours, f K. A. Ainger { Nuclear Licensing Administrator Attachments cc: NRC Region III Office Byron Resident Inspector Braidwood Resident Inspector { LaSalle County Station Resident Inspector i 3386K 4
l ELECTRICAL POWER SYSTEMS 1 SURVEILLANCE REQUIREMENTS l 4.8.1.1.1 Each of the above required independent circuits between the offsite transmission network and the Onsite Class 1E Distribution System shall be: a. Determined OPERABLE at least once per 7 days by verifying correct breaker alignments, indicated power availability, and b. Demonstrated OPERABLE at least once per 18 months during shutdown by f transferring manually unit power supply from the normal circuit to the alternate circuit. 4.8.1.1.2 Each dies ~el generator shall be demonstrated OPERABLE: a. In accordance with the frequency specified in Table 4.8-1 on a STAGGERED TEST BASIS by: 1) Verifying the fuel level in ths day tank, 2) Verifying the fuel level in the fuel storage tank, i 3) Verifying the fuel transfer pump starts and transfers fuel from the storage system to the day tank, 4) Verifying the diesel starts from ambient condition and accelerates to at least 600 rpm in less than or equal to 10 seconds.* The j generator voltage and frequency shall be 4160 1 420 volts and I 60 1 1.2 Hz within 10 seconds
- after the start signal.
The diesel generator shall be started for this test by using one of the following signals: a) Manual, or b) Simulated loss of ESF bus voltage by itself, or J c) Simulated loss of ESF bus voltage in conjunction with'an ESF actuation test signal, or d) An ESF actuation test signal by itself. 5) Verifying the generator is synchronized, loaded to greater than or equal to 5500 kW in less than or equal to 60 seco'nds*, operates with a load greater than or equal to 5500 kW for at'least 60 minutes, and 6) Verifying the diesel generator is aligned to provide standby power to the associated ESF busses. b. At least once per 31 days and after each operation of the diesel where the period of operation was greater than or equal to I hour by checking for and remcVing accumulated water from the day tanks;
- The diesel generator start (10 sec) from ambient conditions shall be performed at least once per 184 days in these surveillance tests.
All other engine starts for the purpose of this surveillance testing may be preceded by an engine pre-lube period and/or other warmup procedures recommended by the manufacturer so that mechanical stress and wear on the diesel engine is minimized. BYRON - UNITS 1 & 2 3/4 8-3 j
1 ELECTRICAL POWER SYSTEMS SURVEILLANCE REQUIREMENTS 4.8.1.1.1 Each of the above required independent circuits between the offsite l transmission network and the Onsite Class 1E Distribution System shall be: Determined OPERABLE at least once per 7 days by verifying correct a. breaker alignments, indicated power availability, and b. Demonstrated OPERABLE at least once per 18 n.onths during shutdown by transferring reanually unit power supply from the normal circuit to the alternate circuit. l 4.8.1.1.2 Each diesel generator shall be demonstrated OPERABLE: In accordance with the frequency specified in Table 4.8-1 on a a. STAGGERED TEST BASIS by i 1) Verifying the fuel level in the day tank, J 2) Verifying the fuel level in the fuel storage tank, 3) Verifying the fuel transfer pump starts and transfers fuel from j the storage system to the day tank, 4) Verifying the diesel starts from ambient condition and accelerates to at least 600 rpm in less than or equal to 10 seconds.* The generator voltage and frequency shall be 4160 + 420 volts and l 60 + 1.2 Hz within 10 seconds
- after the start signal.
The { diesel generator shall be started for this test by using one of J the following ignals: l a) Manual, or b) Simulated loss of ESF bus voltage by itself, or c) Sirnulated loss of ESF bus voltage in conjunction with an ESF actuation test signal, or d) An ESF actuation test signal by itself. 5) Verifying the generator is synchronized, loaded to greater than or equal to 5500 kW in less than or equal to 60 seconds *, operates with a load greater than or equal to 5500 kW for at least 60 minutes, and 6) Verifying the diesel generator is aligned to provide standoy power to the associated ESF busses. b. At least once per 31 days and after each operation of the diesel where the period of operation was greater than or equal to 1 hour by checking for and removing accumulated water from the day tanks;
- The diesel generator start (10 sec) from ambient conditions shall be performed at least once per 184 days in these surveillance tests.
All other engine starts for the purpose of this surveillance testing may be preceded by an engine pre-lube period and/or other warmup procedures recommended by the manufacturer so that mechanical stress and wear on the diesel engine is minimized. f BRAIDWOOD - UNITS 1 & 2 3/4 8-3 L I'
ELECTRICAL POWER SYSTEMS . SURVEILLANCE REQUIREMENTS 4.8.1.1.1 Each of the above required independent circuits between the offsite transmission network and the onsite Class lE distribution system shall be: a. Determined OPERABLE at least once per 7 days by verifying correct breaker' alignments and indicated power availability, and i b. Demonstrated OPERA 8LE at least once per 18 months during shutdown by l manually transferring unit power supply from the normal circuit to the alternate circuit. 4.8.1.1.2 Each of the above required diesel generators shall be demonstrated OPERABLE: ) a. In accordance with the frequency specified in Table 4.8.1.1.2-1 on a STAGGERED TEST BASIS by: 1. Verifying the fuel level in the day fuel tank. 2. Verifying the fuel level in the fuel storage tank. 3. Verifying the fuel transfer pump starts and transfers fuel from the storage system to the day fuel tank. 4. Verifying the diesel starts from ambient condition and accelerates ~ to 900 rpm + 5%, -2% in less than or equal to 13 seconds.* The I generator voltage and frequency shall be 4160 t 150 volts and 60 + 3.0, -1.2 Hz within 13 seconds
- after the start signal.
1 5. Verifying the diesel generator is synchronized, loaded to greater than or equal to 2500 kw within 60 seconds,* and operates with l this load for at least 60 minutes. 6. Verifying the diesel generator is aligned to provide standby power to the associated emergency busses. 7. Verifying the pressure in all diesel generator air start receivers to be greater than or equal to 200 psig. b. At least once per 31 days and after each operation of the diesel l where the period of operation was greater than or equal to 1 hour by checking for and removing accumulated water from the day fuel tanks, c. At least once per 92 days and from new fuel oil prior to addition to the storage tanks by verifying that a sample obtained in accordance with ASTM-0270-1975 has a water and sediment content of less than or equal to 0.05 volume percent and a kinematic viscosity @ 40 C of greater than or equal to 1.9 but less than or equal to 4.1 when tested in accordance with ASTM-0975-77, and an impurity level of less than 2 mg. of insolubles per 100 ml. when tested in accordance with ASTM-D2274-70. ^These diesel generator starts from ambient conditions shall be performed at least once per 184 days in these surveillance tests. All other engine starts for the purpose of this surveillance testing shall be preceded by an engine prelube period and/or other warmup procedures recommended by the manufacturer so that mechanical stress and wear on the diesel engine is minimized. LA SALLE - UNIT 1 3/4 8-3 Amendment No.16 ~
Commonwszith Edissn -{' . (' 2 C ' One First Nabonal Plaza; Chicago, lihnor$ / O Address Reply to. Post Othee Box 767 Chicago. Ilknois 60690 December 9, 1983 Mr. Harold R. Denton, Director Office of-Nuclear Reactor Regulation ) U.S. Nucl' ear Regulatory Commission { Washington, DC 20555
Subject:
LaSalle County Station Units 1 and 2 Request for An Exigent Change to NPF-ll Appendix A Technical Specifications t Regarding Diesel Generator Fast Starts i NRC Docket Nos. 50-373 and 50-374 )
Dear Mr. Denton:
The purpose of this letter is to. request the following exigent. change in Technical Specifications for_LaSalle County Station Unit l'and that the same change be incorporated into the original Unit 2 Technical Specifications. 1 CHANGE REQUEST NPF-ll/83-06 Revise diesel generator specifications to require a " fast start" only 1 once for each. diesel generator each six months. I This proposed change is addressed in Attachment A and has received onsite and offsite review and approval. Guidance for Technical Specification changes states' "Exioent circumstances exist when a licensee and the NRC must act quicxiy and time does not allow a full 30-day notice...". In this case, Commonwealth Edison Company believes that.such action is warranted. Commonwealth Edison Company is requesting'that the LaSalle County Station Unit 2 original Technical Specifications, as part of NPF-18, be issued to minimize " fast ' starts" on the diesel generators. These changes which are being made for the purpose of minimizing mechani-cal stress and wear on the diesel generators, require a concurrent change i in the Unit 1 NPF-ll Technical Specifications because. diesel generators 0, lA, and 2A have surveillance required in accordance_with both sets of' Technical Specifications. The 18 and 28 diesel. generators are addressed only in the. respective Unit 1 and the Unit 2 Technical Specifications. IN ORDER TO ALLOW THIS STEP TOWARD LESS HARMFUL TESTING.0F i DIESEL GENERATORS TO BE TAKEN IN THE PENDING UNIT 2 LICENSE ISSUANCE, AN EXIGENT UNIT 1 CHANGE 15 NECESSARY. i Q j _l n l 6 /" 9 D $ ll(, c ; & p~a s y s w i i
H. R. Denton December 9, 1983 Commonwealth Edison has reviewed this amendment request and has determined that no significant hazard consideration exists. Our review l 1s documented in Attachment B. I Pursuant to 10 CFR 170, this change reflects one example of a Class III amendment. A remittance of $4,000 is, therefore, enclosed. To the best of my knowledge and belief the statements contained herein and in the attachment are true and correct. _In some respects these statements are not based on my personal knowledge but upon infor-mation furnished by other Commonwealth Edison and contractor employees. Such information has been reviewed in accordance with Company practice-and I believe it to be reliable. Commonwealth Edison is notifying the State of Illinois of our request for this amendment by transmittal of a copy of this letter and its attachments to the designated State Official. If you have any questions concerning this matter, please contact this office. j Enclosed please find three (3) signed originals and forty (40) copies of this letter and the enclosures. Very truly yours, b&A m/9/S3 C. W. Schroeder Nuclear Licensing Administrator 1m Attachments cc: Dr. A. Bournia l NRC Resident Inspector - LSCS G. N. Wright (State of Illinois) SUBSCRIBED and SWORN to before me this M day of [ u t w /ut4_; 1983 ut k a h a rc& u Notary Puolic 7763N h
( ATTACHMENT A LaSalle County Station j Technical Specification Change Request Units 1 and 2 q
SUBJECT:
Diesel Generator Testing Requirements REFERENCES (a): LSCS Technical Specification 3.8.1.1 and 4.8.1.1.2. (b): Marked-Up Technical Specification Pages 3/4 8-1, 8-2, 8-3, 8-7 and B 3/4 8-1 for Unit 1 and Unit 2. (c): Memorandum for Power System Branch from Reliability and Risk Assessment Branch dated February 4, 1983, " Frequency of Diesel Generatcr Fast Start Surveillance Testing by Technical Specifications Requirements." BACKGROUND: Reference (a) specifies the requirement for testing the diesel generators. These requirements specify that the diesel generator be started quickly. These quick starts place unnecessary mechanical stress and wear on the diesel engine. In reference (c) the subject of relaxation of fast start surveillance test frequency was investigated and found to be unlikely to impact risk adversely. DISCUSSION: To reduce the mechanical stress and wear on the diesel generators while still maintaining assurance that the j diesel will perform its design function when required, the j requirements to fast start the diesel should be reduced to semiannually (184 days). Rapid startup engine wear is caused by large dynamic forces and heterogeneous component heating. The diesel generetor will still be started at the same frequency as required by reference (a) to meet the surveillance requirements but taese starts will be preceded by an engine prelube period and/or other warmup procedure recommended by the manufacturer so that mechanical stress and wear on the diesel engine is minimized. This change 1 will increase the reliability of the standby diesel generaters since the large number of fast starts will be reduced..while the fast start capability will be verified by the semi-annual fast start. l l l \\ \\
l, DISCUSSION (Cont'd) ] ) The diesel generator starts per Table 4.8.1.1.2-1 will have no time requirements associated with them. These tests will verify correct generator voltage and frequency and i after a warmup period will be synchronized to the grid and j loaded to'2600 kw for'60 minutes but the 13 second (or 60 seconds) time requirements.will not apply.for these starts. l Even though these starts have no start time requirements they will be considered to meet the valid test requirement by Reg. Guide.1.108. The semi-annual (184 days) fast l starts will have time requirements as presently required by Technical Specifications 4.8.1.1.2a.4 and 5. The semi- . annual fast starts will be from ambient conditions without a prior warming up procedure. In addition, since the warmup procedure will require additional manpower to perform and because.it requires additional time to complete the surveillance requirements for slow starts, the time to complete action statements of 3.8.1.1 must be increased. CONCLUSION: Commonwealth Edison believes that this change should be added to the Unit 2 Technical Specification prior to license issue and be added to the Unit 1 Technical y Specification by license admendment as an exigent change. The changes to both documents need to be.made at the same time because three of the LaSalle County Station's five diesel generators are contained in both Technical Specif1-cations and therefore identical surveillance requirements j must be maintained to eliminate unnecessary diesel generator i starts to satisfy two different' Technical Specifications. I J -l i 7763N
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) Orie3Irsi Aational' Eaia[Ch5cago.' ilhnois ( QM l ~ ~ y '~ . Address Reply to: Post Ottice Box 767 1 j ~ Chicago Illinois 60690 ,j 4 ) f '9 T i a 1 January 11,ul984 5 i Mr. Harold R. Denton, Director Office. o f' Nuclear Reactor Regulation U.S.. Nuclear Regulatery Commission. .l Washington, DC 20555 6 s .I t
Subject:
LaSalle County Statio"rr Unit 1 l ~ . Request'for an Exigent Change to NPF-ll Appendix A Technical a Specifications Regarding' Diesel Generator Fast' Starts NRC Docket Nos. 50-373 Reference (a): -C. W. S c h r o'e d e r l e t t e r t o H. ' R. D e n t o 1 dated December'9, 198$.
Dear Mr> Denton:
The purpose of this letter is to modify the wc'rding requested in reference (a) for LaSalle County Station Unit 1. Technical Sp'ecifications. Specifically, the insert for page 3/4 8-3 shoulo read as follows: "These diesel generator starts from amolent conditions:shall be perf,ormed at least once per 184 days in these surveillance tests. All other engine starts for the purpose of surveillance testing shall be preceeded by an engine prelube period and/or warmup procedures recommended by the manufacturer, so that mechanical and wear on the diesel engine is minimized." This change has been discussed with Dr. A. Bournia of your staff. In addition, this proposed wording change has received onsite and o f fsite review and approval. To.the best of my knowledge and belief the sta' aments contained herein and in the enclosure are-true and correct. In some' respects these statements are not based on my personal knowledge but upon information furnisned by other Commonwealth Edison and contractor employees. Such information has been reviewed in accordance.with Company practice and I believe it to be reliable. Commonwealth Edison is notifying the State of Illinois of the change.in our. request for this amendment by transmittal of a. copy of this letter and its enclosures to the designated-State Official, n , m O
- f. pC L
H. R. Denton January ll, 1984 If there are any further questions concerning this matter, please contact this office. Enclosed please find three (3) signed originals and forty (40) copies of this letter and the enclosures. 1 Very truly yours, { i fh)Sp. C. W. Schroeder Nuclear Licensing Administrator 1m i cc: Dr. A. Bournia NRC Resident Inspector - LSCS G. N. Wright - (State of IL) SUBSCRIBED and SWORN to before me this // 6/_ d a y a f}. }n v nu 1984 wn O 'd& (IL l Notary PuoliC 1 I l 7977N i i I \\ \\ _ _ _.}}