ML20151X596
| ML20151X596 | |
| Person / Time | |
|---|---|
| Site: | McGuire, Mcguire  |
| Issue date: | 08/19/1988 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20151X591 | List: |
| References | |
| NUDOCS 8808260040 | |
| Download: ML20151X596 (6) | |
Text
/pn etog'o UNITEo STATES
'g NUCLEAR REGULATORY COMMISSION n
WASHINGTON, D. C. 20%S
\\...../
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 91 TO FACILITY OPERATING LICENSE NPF-9 AND AMENDMENT NO. 72 TO FACILITY OPERATING LICENSE NPF-17 0,U R POWER COMPANY 00CXL. W ). 50-369 AND 50-370 MCGUIRE NUCLEAR STATION, UNITS 1 AND 2
1.0 INTRODUCTION
By letter dated December 17, 1986, Duke Power Company (the licensee) requested a change to McGuire Unit 1 and Unit' 2 Technical Specification (TS) 4.5.1.1.1c which regards the surveillance requirements for power lockout of the ccid leg accumulator isolation valves. Specifically, the present method for disconnecting power to the isolation valves, which is 'by removal of the breaker from the circuit," would be, deleted.
By letters dated February 13, 1987, March 2, 1987, and September 8, 1987, the licensee provided additional information in support of this request. At the request of the NRC, the licensee submitted an addi-itional request on July 13, 1988, which would add TS 4.5.1.1d.
This additional TS would require that each cold leg accumulator be demonstrated operable at least once per 18 months by verifying proper operation of the power disconnect circuit.
The supporting information provided by the licensee's letters of March 2 and September 8, 1987, and the additional associated surveillance requirement requested by the NRC to periodically verify proper operation of the power disconnect circuit, as proposed by the licensee July 13, 1988, do not alter the substance of the changes or the proposed no significant hazards detarmination as noticed in the Federal Reaister on March 12, 1987 2.0 EVALUATION The isolation valves in the discharge pioing of the ECCS cold leg accumulators are required to be open during Operating Modes 1, 2 and 3 to assure that the accumulators can discharge their borated water into the reactor coolant system when needed to mitigate the consequences of a depressurization accident such as a LOCA. Once the valves are in proper ECCS position during startup, the TS requiros that power to the valves be dirconnected, and periodically verified to remain disconnected, in order to assure that the valves do not subsequently change position.
Fower is aresently 6isconnected by removing the breaker from the circuit. The licensee 1as now modified the design of the power lockout circuit for the cold leg accumulator isolation valves and proposes to revise the TS to reflect use of this modification to disconnect power.
0800260040 000019 PDR ADOCK 05000369 P
PNU
2 In its February 13, 1987 letter, the licensee provided an electrical schematic of the power lockout circuit modification provided for the cold leg accumulator isolation valves.
The modificaticn consists of an additional circuit breaker and motor contactor assembly that is inserted in the snotor operator circuit of the accumulator isolation valve between the existing motor contactor and the valve motor.
There is a two position switch (power disconnect switch) located in the control room with one set of contacts in the control circuit of the new inotor contactor operating coil and an additional set of contacts in the seal-in circuit of the existing motor contactor close circuit. When the power discunnect switch is in the disconnect position the new motor contactor will remain open, removing power from the valve motor and preventing spurious or inadvertent actuation of the valve snotor. When the power disconnect switch is in the enable position the new motor contactor will close following closure of the existing motor contactor, thereby allowing the valve motor to operate and reposition the valve.
Under the existing TS requirements, power is removed from cold leg accumulator isolation valve motors by removal of the circuit breaker that supplies power to the valve motor.
The proposed new way of removing power from the valve motor is to place the power disconnect switch described above in the disconnect..
position so that the new rotor contactor prevents connection of power to the valve notor.
The existing McGuire Technical Specification calls for verifying that power to the isolation valve operator is disconnected by removal of the breaker from the circuit at least once per 31 days when the hCS pressure is above 2000 psig. The propcsed new technical specifications deletes the words "by removal of the bresker from the circuit" and, as first requested, called only for verifying at least every 31 days that power to the isolation valve operator is disconnected when RCS pressure is above ?.000 psig.
By letter dated March 2,1987, the licensee indicated that it would verify that power to the isolation valve operator is disconnected by verifying that the power disconnect switch was in the disconnect position and the valve indicator light indicated the valve was open.
The staff reviewed the licensee's submittal and found that the hardware modifi-cations made to achieve power lockout for the cold leg accumulator isolation valves from the main control room were acceptable. However, the staff was concerned about the means that the licensee had indicated it would use to periodically verify the disconnection of power to the isolation valves.
Specifically, the surveillance, which only verified that the power disconnect switch was in the disconnect position and the valve indicator light indicated the valve was open, would not verify that the power lockout circuit was actually functioning.
Thus, the staff was concerned that undetected failures could occur, such as a short or malfunction of the switch contacts, which could result in disabling of the power lockout function.
The staff requested that the licensee provide additional justification for conducting the surveillance as proposed, or that the licensee provide a periodic surveillance that actually verifies the proper functioning of the power lockout i
circuit. B) its September 8, 1987 letter, the licensee responded by comparing the existing and the proposed method of disconnecting power from the cold leg accumulator isolation valves.
The licensee found the number of failures required to close the accumulator isolation valves was the same for each method.
3 However, the licensee also stated that all of the failures for the existing method may be personnel errors, whereas, in the case of the power disconnect switch, two of the failures must be equipment failures of a specific nature.
The licensee therefore concluded that the power disconnect switch, in conjunction with the proposed surveillance, provided at least the same, if not greater, assurance that the valve was open with the power removed as does physically opening the breaker.
The staff disagreed with the above conclusion. Although we recognized the benefit to be gained in terms of reducing personnel errors by locating the power disconnecting means in the main control room where it can be mcu s closely monitored, this advantage is more than offset by the fact that the proper functioning of the power discor.nect circuit would not be checked. With the existing method called for in the McGuire Technical Specification of renoving the breaker from the circuit, the verification that power is removed froin the circuit when this done is obvious.
Even when the breaker is left in the circuit and is the breaker is simply opened, verification that power is actually removed can be checked by the loss of valve position indication in the control room, although the loss of the position indication is not a desirable condition.
No such direct indication of power removal existed with the proposed modifica.
tion. Therefore, the NRC advised the licensee that the proposed surveillance was deficient because periodic surveillarce of the proper functioning of the power disconnect circuitry was also needed.
The licensee responded to this flRC concern on July 13, 1988. The response proposed the addition of new surveillance TS 4.5.1.1.1d which requires verification of the correct o)eration of the power disconnect circuit at least once every 18 months. With tiis addition, the staff finds that removal of power is reasonably assured and, therefore, that the proposed changes e.re acceptable.
3.0 ENVIRONMENTAL CONSIDERATI0h These amendments involve changes in surveillance requirements. The staff has determined that the amendments irvolve no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite and that there is no significant increase in individual or cumulative occupational exposure. The NRC staff has made a determination that the amendments involve no significant hazards consideration, and there has been no public concent on such finding. Accordingly, the amendments meet the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuint to 10 CFR 51.22(b) no envWnmental impact statement or environmental assu sment need be prepared in connection with the issuance of these amendments.
4.0 _ CONCLUSION The Commission made a proposed determinstion that the amendments involve no significant hazards consideration which was published in the Federal Register (52 FR 7681) on Parch 12, 1987. The CommisU on consulted with the state of flerth Carolina. No public coments were received, and the state nf North Carolina did not have any connents.
l i
We have concluded, based on the considerations discussed above, that:
(k) 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 these amendments will not be inimical to the common defense and security or to the healtl: and safety of the 'gublic.
Principal Contributor:
D. Hood, PD#11-3/DRP-1/II Dated:
August 19, 1988
Mr. H. 8. Tucker Duke Power Company McGuire Nuclear Station cc:
Mr. A.V. Carr, Esq.
Or, John M. Barry Duke Power Company Departmant of Environmental Health P. O. Box 33189 Mecklenburg County 422 South Church Street 1200 Blythe Boulevard Charlotte, North Carolina 28242 Char lotte, North Carolina 18203 r
County Manager of Mecklenburg County Mr. Dayne H. Brown, Chief 720 East Fourth Street Radiation Protection Branch Cho.lotte, North Carolina 28202 Division of Facility Services Department of Hvean Resources 701 Barbour Drive lir. Robert Gill Raleigh, North Carolina 27603-2008 Duke Power Ccmpany Nuclear Production Department P. O. Box 33189 Charlotte, North Carnlina 28242 J. Michael McGarry, III, Esq.
Bishop, Liberman, Cook, Purcell and Reynolds 1200 Seventeenth Street. N.W.
Washington, D. C.
20036 Senior Resident Inspector c/o U.S. Nuclear Regulatory Commission Route 4, Box 529 Hunterville, North Carolina 28078 Regional Administrator, Region 11 U.S. Nuclear Regulatory Commission 101 Marietta Street, N.W., Suite 2000 Atlanta, Georgia 30323 S. S. Kilborn Area Manager, Hid-South Area ESSO Projects Westinghouse Electric Corporation MNC West Tower - Bay 239 P, O. Box 355 Pittsburgh, Pennsylvania 15230
DATED:- August 19, 1988 I
AMENDMENT N0. 91 TO FACILITY OPERATING LICENSE NPF McGuire Nuclear Station, Unit 1 AMEN 0HENT NO. 72 TO FACILITY OPERATING LICENSE NPF McGuire Nuclear Station, Unit 2 NRC POR Local POR-P0fil-3 R/F McGuire R/F S. Varga 14-E-4
- G. Lainas 14-H-3 D. Matthews 14-H-25 M. Rood 14-N-25 D. Hood 14-H-25 OGC-WF 15-B-18 B. Grimes 9-A-2 E. Jordan MNBB-3302 W. Jones P-130A T. Barnhart (8)
P1-137 ACRS (10)
H-1016 GPA/PA 17-F-2 ARM /LFNB AR-2015 E. Butcher 11-F-23 D. Hagan HNBB-3302 F. Rosa J. Lazevenick 8-0-20 1