ML20058M959

SE Accepting Licensee Response to GL 89-19, Request for Action Re Resolution of USI A-47, 'Safety Implication of Control Sys in LWR Nuclear Power Plants.'

ML20058M959
Person / Time
Site:	Davis Besse
Issue date:	09/28/1993
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20058M957	List: ML20058M955 ML20058M959
References
REF-GTECI-A-47, REF-GTECI-SY, TASK-A-47, TASK-OR GL-89-19, NUDOCS 9310070197
Download: ML20058M959 (2)

Text

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f(y>2 KEC )t UNITED STATES

[,J@fIj NUCLEAR REGULATORY COMMISSION I

• g, g y WASHINGTON. D.C. 205564001

.g y SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION I TOLEDO EDISON COMPANY '

CENTERIOR SERVICE COMPANY i AliQ THE CLEVELAND ELECTRIC ILLUMINATING COMPANY DAVIS-BESSE NUCLEAR POWER STATION. UNIT NO. 1 DOCKET NO. 50-346

1. INRODUCTION y letter dated March 20, 1990, supplemented August 12, 1993, Toledo Edison oompany (the licensee) responded to Generic Letter (GL) 89-19, " Request for Acticn Related to Resolution of Unresolved Safety Issue A-47 ' Safety Implication of Control Systems in LWR Nuclear Power Plants' Pursuant to 10 CFR  ;

50.54(f)."

2. EVALUATION The licensee responded to GL 89-19 Enclosure 2 Item (3)(a) concerning automatic steam generator overfill protection to mitigate Main feedwater (MFW) overfeed events, that they have a safety grade system (steam and feedwater '

rupture control system (SFRCS)) which addresses this issue. The system has two actuation channels corresponding to the two steam generators, each with a >

two out of two initiating logic. The system will close the MFW isolation valves, the MFW control valves, the main steam isolation valves (MSIVs), and initiate auxiliary feedwater on high steam generator level. Either actuation channel functioning will initiate closure of the MSIVs, which results in the shutdown of the MFW pump turbines. In addition, the licensee states that the design for the overfill-protection system is sufficiently separate from the MFW control system to ensure that MFW isolation occurs on a steam generator (SG) high-water-level signal when required, even if a loss of power, a loss of ventilation, or a fire in the control portion of the MFW control system should occur. The NRC staff has reviewed the licensee's response regarding GL 89-19 Enclosure 2 Item (3)(a) and finds it acceptable.

With regard to GL 89-19 Enclosure 2 Itsm (3)(b), the SFRCS SG high-level trip at Davis-Besse is subjected to surveillance testing similar to the safety-grade SFRCS SG low-level trip which int.ledes channel check, channel functional- '

test and channel calibration (including setpoint verification). However, the 9310070197 930928 PDR ADOCK 05000346 P PDR

i i

high-level trip is not included in the Davis-Besse Technical Specifications (TS). The supplemental letter of August 12, 1993, committed to submit a TS change adding surveillance testing for the SFRCS SG high-level trip by December 17, 1993. The NRC staff finds this response to be acceptable for GL 89-19 Enclosure 2 Item (3)(b). Review of the TS change will be conducted under TAC No. M87443.

The licensee stated that GL 89-19 Enclosure 2 Item (3)(c) does not apply to Davis-Besse, because SFRCS provides automatic protection to prevent SG dryout by automatically initiating auxiliary feedwater on low SG 1evel. TS requirements apply to this automatic action. The NRC staff has reviewed the licensee's response regarding GL 89-19 Enclosure 2 Item (3)(c) and finds it acceptable.

3. CONCLUSION The NRC staff has reviewed the licensee's response to GL 89-19, and based on the above, finds that it is acceptable.

Principal Contributor: J. B. Hopkins Date: September 28, 1993 i