ML20207L354
| ML20207L354 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 05/23/1979 |
| From: | Varga S NRC |
| To: | Boyd R, Case E, Harold Denton NRC |
| References | |
| IEB-79-05A, IEB-79-05B, IEB-79-5A, IEB-79-5B, NUDOCS 8701120110 | |
| Download: ML20207L354 (1) | |
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MM 2 31979 MEMORANDUM FOR:
See Distribution FROM:
Steven A. Varga
SUBJECT:
I&E BULLETIN 79-05B Attached are responses to I&E Bulletin 79-05B from B&W operating plants checked below.
Additional responses will be distributed when received.
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Plants:
-Project Manager:
DISTRIBUTION:
Crystal River Diianni H. Denton E. Case Oconee Fairtile R. Boyd h sing Besse i
iams R. Woodruff Rancho Seco Garner N. Wagner ANO-1 Swetzig V. Stello D. Eisenhut B. Grime s T.
Ippolito R. Reid R. Vollmer D. Davis A. Schwencer D.
Ziemann R.
DeYoung R. Mattson F. Schroeder J.
Knight R. Tedesco S. Hanauer L. Crocker G. Lainas P. Check Project Manager 870152di10 790523 PDR ADOCK 05000346 Q
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%s EDISON JAMES S. GRAPR May 15, 1979 v.c= Pr==
ai Energy Sweesy (4193 259-5232 Docket No. 50-346 License No. NPF-3 Serial No. 1-67 Mr. James G. Keppler Regional Director, Region III Office of Inspection and Enforcement U. S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137
Dear Mr. Keppler:
This letter is to identify a change in the Davis-Besse Nuclear Power Station Unit 1 response to IE Bulletin 79-05B, item 4.
Enclosed is page 4-1 that revises Toledo Edison's May 4, 1979 (Serial No. 1-65) transmittal.
The effect of the change is that Davis-Besse Unit 1 procedures will not now be modified to provide a manual reactor trip on low pressurizer level. This is a more proper response, because-low pressurizer level is associated with underprescurization rather than overpressurization events. A reactor trip would only aggravate the problem during an underpressurization event as it removes the primary heat source; therefore, our current procedures calling for increasing reactor coolant makeup on decreasing level will be uneffected.
The reactor core will continue to be protected by the low RC pressure trip as analyzed in the FSAR.
Yours very truly, JSG:TJM/pm ene.
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U. S. Nuclear Regulatory Commission Office of Inspection and Enforcement Division of Reactor Operations Inspection Washington, D. C.
20555
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THE TOLEDO EDISCN COMPANY EDtSON PLAZA 300 MACISCN AVENUE TCLECO, CHIO 43E52
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. Docket No. 50-346 License No. NPF-3 Serial No. 1-67 May 15, 1979 Item 4 Provide procedures and training-to operating personnel for a prompt manual trip of the reactor for transients that result in a pressure increase in the reactor coolant system. These transients include:
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Loss of main feedwater i
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Turbine trip Main Steam isolation Valve closure #
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Loss of off-site power e.
Low OTSG level 3
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Low pressurizer level
Response
A hard wired reactor trip on the loss of main teedwater and on a turbine trip will l
be installed prior to Mode 3 operation.\\ rocedures will be prepared and the P
operators will be instructed to manually trip the reactor on the closure of the nain steam line isolation valve, a Anon low staan generat_otlastals, prior to Mode 3 operation. Procedures will be prepared and the operators will be trained to confirm that the reactor has automatically tripped upon a total loss of off-site power which has forced the Emergency Diesel Generators to start. However, if the main turbine-generator is isolated free the 345 KV transmission system and it is supplying the unit's house power (including reactor coolant pumps), then the reactor will not be manually tripped. If the reactor were tripped under this condition, the main turbine generator wculd also be tripped which would result in an unnecessary a
momentary loss of AC power, which would force the Emergency Diesel Generators to start. Also, this tripping would case the loss of forced reactor coolant circulation.
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4-1 Revised May 15, 1979
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y" Seri:1 No.1-68 Item 3 Following detailed analysis, describe the, modifications to design and procedures which you have implemented to assure the reduction of the likelihood of automatic actuation of the pressurizer PORV during anticipated transients.
This analysis shall include consideration of a modification of the high pressure scram setpoint and the PORV opening setpoint such that reactor scram will preclude opening of the P0kV-for the spectrum of anticipated transients discussed by B&W in Enclosure 1.
Changes developed by this analysis shall not result in increased frequency of pressurizer safety valve operation for these anticipated transients.
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Response
Evaluations of the Davis-Besse Nuclear Power Station Unit 1 (DB-1) were performed to consider modifications which would assure the reduction of the likelihood of automatic actuation of the pressurizer PORV during anticipated transients.
The results of these evaluations identified that coincident reduction of the high reactor coolant system (RCS) pressure trip setpoint and elevation of the PORV setpoint would resolve this. At Davis-Besse Unit 1, the high RCS pressure trip is to be reduced from a nominal 2355 psig to-2300 psig. The PORV opening setpoint is to be raised to 2400 psig.
This will assure the reduction of the likelihood of automatic actuation of the pressurizer PORV during anticipated transients.
It should be noted that Davis-Besse Unit I has nominal pressurizer code saf ety valve lift settings of 2435 psig in accordance with " Davis-Besse Nuclear Power Station Unit 1 Technical Specifications" No. 3.4.3.
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( (((/ /t TotEDO EDISON JAMES S. GRANT v.c. w..
May 18, 1979 rwsu s.or,
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Docket No. 50-346 License No. NPF-3 f :7)' l $*
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Serial No. 1-68 L.
Mr. James G. Keppler Regional Director, Region III Office of Inspection and Enforcement U. S. Nuclear Regulatory Comission 799 Roosevelt Road Glen Ellyn, Illinois 60137
Dear Mr. Keppler:
This letter is to further respond to IE Bulletin 79-05B for the Davis-Besse Nuclear Power Station Unit 1.
The attached page 3-1 addresses item 3 of the Bulletin whose response is required prior to Davis-Besse Unit I resuming operation.
Additionally, minor changes are being incorporated into the station's procedures to reflect revisions to Babcock and Wilcox's operating guidelines.
These changes were made as a result of NRC coments and alter, in part, item 2 of the May 4, 1979 (Serial No. 1-65) response.
Yours very truly, Y#
JSG:TJM Attachment ec:
U. S. Nuclear Regulatory Commission Office of Inspection and Enforcement Division of Reactor Operations Inspections Washington, D.C. 20555
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THE TOLEDO EDISON COMPANY EDISON PLAZA 300 MADISON AVENUE TOLEDO, OHIO 43652