ML20210G168
| ML20210G168 | |
| Person / Time | |
|---|---|
| Site: | McGuire, Mcguire  |
| Issue date: | 09/17/1986 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20210G152 | List: |
| References | |
| NUDOCS 8609250346 | |
| Download: ML20210G168 (5) | |
Text
-
/
o UNITED STATES 8
NUCLEAR REGULATORY COMMISSION o
r, ej WASHINGTON, D. C. 20u55 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT N0. 62 TO FACILITY OPERATIN3 LICENSE NPF-9 AND AMENDMENT N0. 43 TO FACILITY OPERATING LICENSE NPF-17 DUKE POWER COMPANY DOCKET NOS. 50-369 AND 50-370 McGUIRE NUCLEAR STATION, UNITS 1 AND 2 INTRODUCTION _
The NRC staff has reviewed certain requests by Duke Power Company (the licensee) for license amendments to change Technical Specifications (TS) for McGuire Nuclear Station, Units 1 and 2.
The changes would (1) authorize use of McGuire's
" Turbine Overspeed Reliability Assurance Program" for demonstrating operability of the turbine overspeed protection system, (2) increase the time during which an inoperable turbine stop valve instrument channel may be maintained in an un-tripped condition, and (3) increase the number of reactor coolant loops required to periodically be verified in operation in the hot standby mode. Our evalua-tion of these three changes follows.
EVALUATION Turbine Overspeed Protection By letter dated August 30, 1985, the licensee proposed changes to delete the surveillance requirements in McGuire TS 3/4.3.4, " Turbine Overspeed Protection".
The changes would revise the surveillance requirements of TS 4.4.3.2 by deleting the existing requirements for demonstrating the Turbine Overspeed Protection System to be operable, and substituting a requirement that operability of this system be assured by inservice inspection of the various system components carried out in accordance with a " Turbine Overspeed Reliability Assurance Program" (TORAP). Associated TS Bases 3/4.3.4 " Turbine Overspeed Protection" would also be revised to reflect implementation of TORAP.
The McGuire TORAP is a comprehensive program for testing, calibration, main-tenance and inspection of the Turbine Overspeed Protection System. The overall intent of this program is to maintain the reliability and operability of the Turbine Overspeed Protection System to minimize the potential for turbine missile generation. The Program is described as follows:
(A) The McGuire testing program addresses the turbine valves and the turbine overspeed protection controls. The testing program is performed during each turbine startup, unless tested within the previous 7 days, including startup after each refueling outage.
This program also includes a test of all the turbine valves on a 4 months interval; 8609250346 860917 PDR ADOCK 0000 9
i I
P
q (B)
Calibration of the electrical and mechanical overspeed trip devices 1
is performed during each refueling outage or following major main--
tenance on the turbine or the overspeed protection control systems; and (C)
The turbine valve maintenance program includes inspection and maintenance of all throttle, governor, reheat stop and intercept valves every 40 months. This work consists of removing valve internals and cleaning, inspecting, and repairing valve components.
i In September, 1982, Westinghouse published reports, WCAP-10161 (Proprietary) and WCAP-10162 (Nonproprietary) entitled " Evaluation of Impact of Reduced Test-ing of Turbine Valves." The reports present a study of reduced testing of turbine valves at the Farley Nuclear Plant. The study concluded that turbine valve operability and reliability are not significantly affected by lengthening the valve testing interval. The study also concluded that good operating ex-perience and we W planned maintenance, calibration, testing and inspection programs provide a reasonable bases to increase the valve testing interval at Farley. Since early 1983, Westinghouse has fonnally recomended a monthly valve testing interval to its customers who have similar turbines. As indicated in the SER accompanying Farley Unit I license Amendment 41 and Farley Unit 2 license Amendment 32, the staff has concurred that the valve testing interval could be increased without significantly affecting the probability of turbine missile generation.
In its application for amendments dated August 30, 1985, and a supplemental letter of December 13, 1985, Duke Power Company provided a study that shows McGuire has the same or very similar equipment in the Turbine Overspeed Protection System as Farley. Hence, Duke Power Company, has used the Farley TORAP to establish a similar TORAP at McGuire. The Farley TORAP is described '
j in a letter from Alabama Power Company to the NRC dated October 6, 1983 and a supplemental letter dated November 28, 1983.
The staff has evaluated these McGuire submittals using insights and experiences that were gained from its review of Farley. The staff review primarily l
focused upon three considerations; (A) whether compt'aents in the Turbine Overspeed Protection System at McGuire and Farley Nuclear Stations are indeed similar;-(B) whether McGuire and Farley have the same TORAP; and (C) whether the McGuire TORAP follows the intent of the surveillance requirements which l
would be replaced in the revised TS 4.3.4.2.
1 In its supplemental letter of December 13, 1985, the licensee showed that the l
major turbine valves and overspeed trip devices of the Turbine Overspeed Pro-tection System are identical at McGuire and Farley. Major system components
(
1.e., throttle valves, governor valves, intercept valves, reheat stop valves and mechanical overspeed trip device have the same style numbers (part numbers) at McGuire and Farley. The style numbers are listed in the Westinghouse Steam Turbine Division Interchangeability Data Southeastern Area Utilities book.
The electronic overspeed protection circuits are also identical because both Farley and McGuire have the same Westinghouse digital electro-hydraulic control l
systems. Because of similarity in the system components at both plants, Duke j.
Power Company extrapolated the results of the Farley study to McGuire. The l
i
7 4
sa t
1 only difference between McGuire and Farley TORAP regards the valve maintenance intervals. McGuire's TORAP recuires that all major turbine valves be inspected j
every 40 months; whereas Farley's TORAP requires that all throttle and governor valves be inspected every 39 months and all reheat stop and intercept valves every 60 months. Moreover, Duke Power Company proposed the same maintenance 1
periods on the throttle valves, governor valves and overspeed devices (elec-t trical.and mechanical) as Farley but proposed more stringent maintenance periods on the intercept and reheat stop' valves (40 month inspections vs. 60 month).
N As part of its program, Duke Power Company will be disassembling and inspecting
- all turbine valves on a-40 month basis instead of just one of each type valve every 40 nonths as required by TS prior to these amendments. This increased inspection and maintenance schedule increases the reliability of the Overspeed Pictection System and is, therefore, acceptable.
f The staff finds that the McGuire TORAP will accomplish the purpose of the surveillance requirements and, therefore, that replacing the surveillance requirements-irr TS 4.3.4.2 with the' TORAP is acceptable.
In its lettet* of August 30, 1985, the licensee notes that TORAP'will be the subject of on-going review and evaluation such that changes in scope and schedule may occur periodically. The licensee states that this program and any subsequent changes will be reviewed and approved in accordance with its administrative procedures (i.e., any related changes to specified maintenance, calibration or testing activities will be evaluated by Duke Power Company to determine if operability of the turbine overspeed protection system has been affected and appropriate action taken). Because subsequent changes to TORAP can affect the potential for, and effects of, turbine missile generation as analyzed and discussed in McGuire FSAR Sections 3.5.2.7 and 10.2.3, such changes are also subject to the requirements of 10 CFR 50.59.
On the basis of the licensee's statement and the Commission's regulations, the staff con-cludes that subsequent changes to TORAP will be appropriately evaluated by the licensee and, if made without prior Connission approval, are not likely to involve an unreviewed safety question.
Turbine Trip / Reactor Trio System Outage Times On February 21, 1985, the NRC staff issued a letter containing its Safety Evaluation Report (SER) on the Westinghouse Technical Specification (TS) l Optimization Program for increased surveillance intervals and out-of-service times for testing and maintenance of the Reactor Trip System. The Optimiz-ation Program proposal was set forth in WCAP-10271, " Evaluation of Surveillance Frequencies and Out-of-Service-Times for the Reactor Protection Instrumentation System," and Supplement I thereto.
In response to licensee's request by lette; of July 22, 1985, the Commission issued license Amendments 54 for McGuire Unit 1 and 35 for McGuire Unit 2 to authorize several of the changes from the Optimization Program proposal.
However, approval of one of the requested changes was deferred pending further consideration by the licensee. By letter dated June 12, 1986, the licensee addressed this change. The change would modify Action Statement 11 of TS Table j
3.3-1 so as to increase from one to six hours the time during which an inoper-able turbine stop valve instrument channel associated with the turbine trip / reactor trip system may be maintained in an untripped condition.
r We find this change to be consistent with those which we reviewed and accepted for the Optimization Program proposal. Therefore, the staff finds this change acceptable on the basis set forth in the staff's February 21, 1985, SER.
j Reactor Coolant Loops for Hot Standby i
These amendments change Technical Specification 4.4.1.2.3 to require that at least two, rather than at least one, reactor coolant loops shall periodically be verified in operation and circulating reactor coolant when the plant is operating in the hot standby mode.
(A reactor coolant " loop" includes its primary piping, steam generator and reactor coolant pump).
In response to the licensee's letter of January 10, 1986, the NRC issued license Amendment 56 on Unit I and license Amendment 37 on Unit 2 to change the Limiting Condition for Operation associated with Technical Specification 3.4.1.2, " Reactor Coolant System - Hot Standby," by increasing by one the number of reactor coolart loops reouired to be operable and in operation for hot standby.
In its safety evaluation fer-Amendments 56 and 37, the Commission noted that the change to the more restrictive condition was necessary to ensure that sufficient coolant flow is-available when operating in hot standby so that the DNB design bases are met for all operating conditions and postulated accidents in hot standby.
By letter dated May 12, 1986, the licensee noted that its January 10, 1986, letter had also requested a corresponding-change to Surveillance Specification 4.4.1.2.3 which had not been reflected in Amendments 56 and 37. Thus, upon issuance of Amendments 56 and 37, the surveillance requirement was inconsistent (i.e., less restrictive) with its associated limiting condition for operation.
The present amendments correct this inconsistency.
The change to increase by one the number of reactor coolant loops required periodically to be verified in operation and circulating reactor coolant in the hot standby mode represents a more restrictive surveillance requirement in the Technical Specifications.
It has no adverse impact upon safety and is, therefore, acceptable.
ENVIRONMENTAL CONSIDERATION These amendments involve changes.to the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and changes in surveillance requirements. We have determined that the amendments involve no significant increase in the ainounts 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 radiation exposure. The NRC staff has made a proposed detennination that the amendments involve no signi-ficant hazards consideration, and there has been no public connent on such finding. Accordingly, the amendments meet the eligibility criteria for cate-gorical exclusion set forth in 10 CFR 51.22(c)(9). Pursuant to 10 CFR 51.22(b) no environmental impact statement or environmental assessment need be prepared in connection with the issuance of these amendments.
i
r
.. o CONCLUSION The Commission made proposed determinations that the amendments involve no significant hazards considerations which were published in the Federal Register (50 FR 51622) on December 18, 1985, (51 FR 22234) on June 18, 1986, and (51 FR 27283)onJuly 30, 1986, and consulted with the state of North Carolina. No public comments were received, and the state of North Carolina did not have any comments.
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 cornpliance with the Commission's regulations, and the issuance of these amendnents will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributors: Darl S. Hood, PWR #4 PWR Licensing-A F. Burrows, Electrical, Instrumentation and Control Systems Branch J. Tsao, BWR Engineering Branch Dated:
september 17, 1986 t
9 Mm e
- e e