ML20056E169
| ML20056E169 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 08/12/1993 |
| From: | Storz L CENTERIOR ENERGY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| REF-GTECI-A-47, REF-GTECI-SY, TASK-A-47, TASK-OR 2164, GL-89-19, TAC-M74935, NUDOCS 9308200170 | |
| Download: ML20056E169 (3) | |
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- GNTERf0R ENE8HW Louis F. Storr 300 Madison Avenue Vice President - Nuclear 1oledo, OH 43652-0001 Davis-Besse (419)249 2300 Socket Nu.nber 50-346 License Number NPF-3 Serial Number 2164 August 12, 1993 United States Nuclear Regulatory Commission Document Control Desk Vashington, D. C.
20555 Subj ect: Response to NRC Generic Letter Number 89-19: Request for Action Related to Resolution of Unresolved Safety 1ssue A-47
" Safety Implication of Control Systems in LVR Nuclear Power Plants" Gentlemen:
This letter is submitted by the Toledo Edison Company to address-the remaining open issue for the Davis-Besse Nuclear Pever Station' Unit Number 1 (DBNPS) in response to NRC Generic Letter Number 89-19,
" Request for Action Related to Resolution of Unresolved Safety Issue A-47" (Toledo Edison Log Number 3091 dated September 20, 1989).
Generic Letter Number 89-19 discussed that as a result of the NRC staff's technical resolution of Unresolved Safety Issue (USI) A-47, it was determined that protection should be provided for certain control system failures, and that selected emergency procedures should assure that plant transients resulting from control sy. tem failures do not compromise public safety. As a result of this :schnical resolution, the NRC staff concluded that all pressurized va'er reactor (PVR) plants should provide automatic steam generator overfill protection.
Furthermore, the NRC staff concluded that plant procedures and Operating License Appendix A Technical Specifica!bns r,hould include provisions to verify periodically the operability or
- .he overfill protection and to assure that automatic overfill protaction is available to mitigate main'feedvater (MFW) overfeed during reactor power operation.
In Toledo Edison's response (Serial Number 1783, dated March 20, 1990),
J CD it was stated that the DBNPS has in place a Steam and Feedvater Rupture C.1 Control System (SFRCS) trip on Steam Generator (SG) high level that C
closes the MFV isolation valves, the MFV control' valves, tfie Main Steam g
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Docket Number 50-346 License Number NPF-3 Serial Number 2164 Page,2 Isolation Valves (MSIVs), and initiates auxiliary feedwater (AFW).
This is a safety-grade trip using two actuation channels with a 2-out-of-2 per actuation channel initiating logic. The closure of the MSIVs removes the main steam supply to the Main Feedwater Pump Turbines (MFPTs) which causes their shutdown. The MFPTs are not tripped separately. The design for the overfill-protection system is sufficiently separate from the MFV control system to ensure that MFW isolation occurs on a steam generator high-water-level signal when t
required, even if a loss of power, a loss of ventilation, or a fire in the control portion of the MFV control system should occur.
l Generic Letter 89-19 recommended including in the Technical Specifications a provision to verify periodically the operability of overfill protection. Toledo Edison considered this recommendation generic and referred it to the Babcock and Wilcox Owners Group (BV0G) committee on technical specification improvements. The BV0G and the NRC staff discussed the issue. After discussion, the BV0G recommended i
that each Babcock and Vilcox plant separately determine if a Technical Specification for overfill protection is appropriate.
t Toledo Edison currently subjects the SFRCS SG high level trip to surveillance testing similar to the surveillance testing required for other SFRCS instrumentation. The testing includes a channel check, channel functional test and channel calibration. Because the DBNPS i
currently performs this testing and in order to take credit for the SFRCS SG high level trip in the Updated Safety Analysis Report, Toledo Edison plans to submit a license amendment application by December 17, 1993, adding SFRCS SG high level trip surveillance testing to the Technical Specifications.
In the NRC letter dated April 18, 1990, to the Toledo Edison Company, (Log Number 3220) Enclosure 2 states that USI A 47, " Safety Implication of Control Systems in LVR Nuclear Power Plants," is resolved in all respects except for the SG high level trip TS.
Vith the submittal of this letter and commitment to propose TS for the SFRCS SG high level trip, Toledo Edison has addressed the remaining open item for the DBNPS from Generic Letter 89-19.
Should you have any questions or require additional information, please contact Mr. Dale R. Vuokko, Manager - Regulatory Affairs (Acting), at (419) 249-2366.
Very truly yours, G*eu
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Q FVK/dle ec:
J. B. Hopkins, NRC Senior Project Manager J. B. Martin, Regional Administrator, NRC Region III S. Stasek, DB-1 NRC Senior Resident Inspector Utility Radiological Safety Board i
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Docket Number 50-346 License Mumber NPF-3 Serial Number 2164 Enclosure Page' 1 RESPONSE TO NRC GENERIC LETTER
" REQUEST FOR ACTION RELATED TO RESOLUTION OF UNRESOLVED SAFETY ISSUE A-47" FOR l
DAVIS-BESSE NUCLEAR POWER STATION UNIT NUMBER 1 This letter is submitted in conformance with Section 182a, Atomic Energy Act of 1954, as amended, and 10CFR50.54(f) in response to Generic Letter Number 89-19 " Request for Action helated to Resolution of Unresolved Safety Issue A-47."
By:
k L. F. Storz, Vice Presfdent - Nuclear Sworn and subscribed before me this 12th day of August, 1993.
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Y/d/l/h Af0 Notsry FuW ic, State of Ohio
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