ML20149H516
| ML20149H516 | |
| Person / Time | |
|---|---|
| Site: | Cooper  |
| Issue date: | 02/11/1988 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20149H515 | List: |
| References | |
| NUDOCS 8802190302 | |
| Download: ML20149H516 (2) | |
Text
_ - _ _ _ _ _ _ - _ _
J E(psagjo UNITED STATES g
g NUCLEAR REGULATORY COMMISSION 3
j WASHING TO N, D. C. 20555
\\
/
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.115TO FACILITY OPERATING LICENSE NO. DPR-46 NEBRASKA PUBLIC POWER DISTRICT COOPER NUCLEAR STATION DOCKET NO. 50-298
1.0 INTRODUCTION
Ey letter dated December 1, 1987, to licensee requested an amendment to the facility Technical Specifications to (1) revise the Sour:,e Range Monitor (SRM) and Intet-mediate Range Monitor (IRM) operability require-ments to clarify that negative power supply voltage is required for opera-bility, (2) delete operability and surveillance requirements for certain post-accident monitoring instrumentation during shutdown and refueling con-ditions, and (3) revise an incorrect statement regarding the main steam line (MSL) high flow isolation instrumentation setpoint.
2.0 DISCUSSION l
A.
On June 16, 1986, wb le in the refueling mode of operation, a 6WR/3 facility experienced multiple failures of IRM 3/4 Ampere fuses connected to the 124 VDC bus.
The event was caused by a surge in the 24 VDC system resulting from a transient while switching on the 480 VAC power supply.
After replacing only the blown fuses for the 124 VDC bus all inoperative IRM channels appeared to be operating normally.
The loss of signal processing, which requires -24 VDC, was not detected until later surveillance tests were conducted prior to startup.
During the period of loss of
-24 VOC power, certain signal processing functions of the SRM and IRM systems were lost rendering the systems inoperable.
Subsequently, the NSSS vendor recommended a plant modification to provide negative voltage sensing relays to trip SRM/IRM channels to INOPERABLE status upon loss of -24 VDC power (General Electric Co. Service Irdormation Letter 445).
Such instrumentation was provided originally for the
+24 VDC power supplies only.
Evaluation:
The protective functions provided by the SRM and IRM systems are not required for protection against the analyzed tran-sients and accidents applicable to Cooper.
For the Rod Withdrawal Event and Control Rod Drop Event, the 120 percent APRM trip function, which is not affected by loss of negative voltage, is credited for protection.
The modification is, however, desirable for the purpose of providing backup protection during plant operation and core moni-toring during subcritical operations.
The proposed modification will be implemented in accordance with criteria for ESSENTIAL (safety grade) equipment ano is consistent with Paragraph III.2.c of Standard Review Plan Section 7.2 which requires power supply fail-safe design of Reactor Protection Systems.
8802190302 800211 PDR ADOCK 05000298 P
6
, l B.
Post Accident Monitoring Instrumentation:
Section 3.2.H of the Technical Specifications requires that a minimum number of operable channels fur the High Range Noble Gas Monitor for the Elevated Release Point. the Turbine Building Ventilation Exhaust Gas Monitor, the Radwaste/Augumented Racwaste High Range Noble Gas Monitor, and the Primary Containment Gross Radiation Monitor be operable at all times.
The proposed amendment would revise applicability requirements to suspend the operability requirements during shutdown and refueling conditions.
This would facilitate maintenance and testing. The cur-rent operability requirenants were implemented in Amendment 90 which added new Technical Specifications based on staff guidance provided by Generic Letter (GL) 83-36. The GL 83-36 guidance allows that the in-struments be inoperable during shutdown and refueling (conditions other than Mudes 1. 2. and 3). however. Amendment 90 as issued did not contain such a provision. The proposed amendment would correct that deficiency and is therefore acceptable.
C.
hSL High Flow Setpoint:
In Amendment 96 the MSL High Flow Isolation Setpoint was reviseo from 140% of rated flow to 150% of rated flow.
Due to an acministrative oversight in preparation of the amendnent..
one ut the attected pages of the Technical Specifications (Page 52) ~
was not revised. The proposed amendment would revise Page 52 to be consistent with Pages 50 and 84 as amenced in Amendment 96. This change is therefore acceptable.
3.0 ENVIRONMENTAL CONSIDERATION
S This amendment involves changes in the use of a facility component located within the restricted area as defined in 10 CFR Part 20 and changes in test requirements. The staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the types, of any ef fluents that may be released of fsite, and that there is no significant increase in individual or cunciative occupational radiation expcsure. The Commission has previously issued a proposed finding that the agendment involves nc significant hazards consideration and there has been no public comment on such finding. Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFR 51.22(b), oc environmental impact state-ment or env'ironmental assessment need be prepared in connection with the issuance of the amendment.
4.0 CONCLUSIGH We have concluded, based on the considerations discussed above, that (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and (2) such activities will be conducted in compliance with the Commission's regulations.
and the issuance of the amendment will not be inimical to the common defense ano security or to the health and safety of the public.
Date: February 11, 1988 Prir41 pal Contributor: William Long
..