ML20247N373

Safety Evaluation Supporting Amends 76 & 64 to Licenses NPF-10 & NPF-15

ML20247N373
Person / Time
Site:	San Onofre
Issue date:	08/30/1989
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20247N362	List: ML20247N357 ML20247N373 ML20247N385
References
NUDOCS 8909260205
Download: ML20247N373 (5)

Text

._

go ctog'o 0

UNITED STATES

[" g(/h, NUCLEAR REGULATORY COMMISSION nN,4mj WASM NGTON, D. C. 20555

>v f

SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 76 TO FACILITY OPERATING LICENSE NO. NPF-10 AND AMENDMENT NO.-64 TO FACILITY OPERATING LICENSE NO. NPF-15

~

SOUTHERN CALIFORNIA EDISON COMPANY SAN DIEGO GAS AND ELECTRIC COMPANY THE CITY OF RIVERSIDE, CALIFORNIA THE CITY OF ANAHEIM, CALIFORNIA SAN ONOFRE NUCLEAR GENERATING STATION, UNITS 2 AND 3 DOCKET NOS. 50-361 AND 50-362

1.0 INTRODUCTION

By letters dated May 19, 1988, and March 10, 1989, Southern California Edison Company (SCE), et al.. (the licensees) requested enanges to the Technical Specifications for Facility Operating Licenses No. NPF-10 and No. NPF-15 that authurize operation of San Onofre Nuclear Generating Station (SONGS), Units 2 and 3 in San Diego County, California. These requests - designated as PCNs 246 and 290 - proposed to extend the inter-val for certain of the required 18 month surveillance tests in order to support the nominal 24 month fuel cycle. Bnth Units 2 and 3 are operating in their first such cycle and will be required to shut down to perform the 18 month surveillance unless the required interul is extended.

SCE has submitted proposed changes to cover all the 18 month surveillance tests which cannot be performed during plant operation. Many of these requests I

would have changed the required interval from "at least once every 18 months to "at least once per refueling interval. By letter dated March 1

20, 1989, SCE amended these requests to define " refueling interval" as 24 months. This definition has been included in the Frequency Notation table of the Technical Specifications (Table 1.2) by Amendments 73 and 61

)

to Licenses No. NPF-10 and No. NPF-15 respectively.

j

)

2.0 DISCUSSION AND EVALUATION By letter dated May 19, 1988, the licensees proposed to change Technical Specification 3/4.7.6, " Snubbers," to extend the 18 month surveillance I

interval to at least once per refueling interval (24 months). Specifica-l l

tion 3/4.7.6 delineates the operability requirements for snubbers, defines an augmented inservice inspection program to demonstrate operability, and specifies compensatory actions to be taken when the operability require-l ments are not met.

8909260205 890830 PDR ADOCK 05000361 P

pg i

\\

).

Operability of snubbers ensures that the structural integrity of the Reactor Coolant System and all other safety related systems is maintained during and following a seismic event or any other event which imparts dynamic loads. Surveillance Requirement 4.7.6.b requires a visual inspec-tion of all snubbers on a regular basis. The interval for visual inspec-tions is decreased as a function of the number of inoperable snubbers discovered. With no inoperable snubbers found, a maximum interval of 18

~

months'plus or minus 25% is allowed.

With one inoperable snubber per inspection period, the interval is 12 months plus or minus 25%. The proposed change would increase the maximum interval to 20 months plus or minus 25% and would increase the interval for the one inoperable snubber case to 14 months plus or minus 25%. Surveillance Requirement 4.7.6.d requires that a representative sample of at least 10% of each type of snubber be functionally tested at least once per 18 months. The proposed change would increase the interval for functional testing to 24 months, would increase the sample size from 10% to 15%, and would revise the bases to be consistent with these changes. Surveillance Requirement 4.7.6.1 requires a service life review of the installation and maintenance records for each snubber at least once per 18 months to verify that the service life has not been exceeded and will not be exceeded prior to the next scheduled review. The proposed change would increase th: interval for the service life review to 24 months.

SCE states that a review of the test history of this surveillance would have limited applicability because of the snubber reduction program which is currently underway and because of the number of design changer which add or delete snub 6crs. SCE also provides an aralysis which shows that a functional test interval of 24 r:onths with a sample size of 15% provides e higher level of operability than an interval of 18 months with a semple size of 10%.

The staff has evaluated the licensees' submittal. The proposed change te the visual inspection interval would add 2.5 months to the allowable interval for both the maximum and the single inoperable snubber cases. We have determined that this small increase would not significantly decrease snubber reliability for a one time extension of the intervals.

In addition, the increased sample size for the functional test more than compensates for the increased functional test intervul, so that it also tends to compensate to some degree for the increased visual inspection interval.

The service life monitoring program is independent of interval since it determines whether the service life will be exceeded prior to the next service life review, whenever that is scheduled to occur. For these redsons, and because the staff is preparing a branch technical position or generic letter on snubber surveillance testing, we find the change proposed by the licensees to be acceptable on a one time only basis. Therefore, we have modified the proposed changes to indicate the one time only approval.

The staff position on a permanent change to the surveillance interval will be provided in the branch technical position or generic letter.

l.

i PCN-290 By letter dated March 10, 1989, the licensees proposed to add a new Technical Specification 3/4.10.7, "Special Test Exceptions, 18 Month Channel Calibrations," to the Unit 2 license to allow a one time extension I

of the 18 month channel calibrations for 52 Reactor Protective System (RPS), Engineered Safety Features Actuation System (ESFAS), Remote Shut-down Monitoring, and Accident Monitoring instruments. The proposed 4

calibration interval for cycle 4 would extend to "the cycle 5 refueling outage.... or October 1,1989, whichever occurs first."

(October 1, 1989, is 24 months from the date of the last surveillance of the instrument

~

which needs to be calibrated first.) By letter dated May 15, 1989, SCE provided additional justification for the proposed change. By letter dated June 30, 1989, SCE modified their request to delete 49 instruments that were calibrated during the unscheduled outage in May and June of 1989, and to extend the interval to "the scheduled cycle 5 refueling outage, or October 18, 1989, whichever comes first" for the remaining three instru-ments.

(October 18, 1989, is 24 months from the date of the last surveil-lance of the instrument which needs to be calibrated first.) Those three instruments are 1) Pressurizer Level on Remote Shutdown Panel LO42,

2) Pressurizer Pressure - High Range on Remote Shutdown Panel L411, and

3) the Pressurizer Water Level accident monitoring instrument.

Operability of the remote shutdowr. instrumentation on Panel LG42 ensures that sufficient capability is available to permit shetdows and maintenance of NOT STANDBY of the facility from iccations outside tLe c(norol room in the event of control room inhabitability. Operability of the rer:ote shutdown instrumentation on Panel L411 ensures that sufficient capability is available to permit shutdown and maintenance of COLD SHUTDOWN of tne f acility in the event of a fire in the cable spreading room, control room, or Remote Shutdown Panal Lt'4L Operability of the eccident monitoring instrumentation ensuras that sufficient information is available on selected plant parameters to monitor and assess these varihbles following an accident. SurveillanceRequirements(SRs)4.3.3.5and4.3.3.6 require each remote shutdown monitoring and accident monitoring instrument, i

l respectively, to be demonstrated operable by, in part, performance of a channel calibration at least once per 18 months.

Technical Specification 4.0.2 allows a 25% extension of surveillance intervals, for a maximum interval of 22.5 months between channel calibra-tions.

l This 22.5 month interval will expire on September 1,1989, for the remote shutdown monitoring and accident monitoring pressurizer level instruments.

It will expire on September 30, 1989, for the remote shutdown monitoring pressurizer pressure instrument.

r 4

1

?

1 By letter dated May 15, 1989, SCE provided the results of a detailed study of past instrument drift in support of this request. The study examined the long term drift characteristics of transmitters and statistically l

adjusted this drift to reflect the maximum drift expected over 30 months at a 95% probability and a 95% confidence level.

The staff has evaluated the licensees' submittal.

Because the scheduled l

start of the cycle 5 refueling outage has been changed to September 8, 1989, the channel calibration extension required to prevent. unnecessary plant shutdown has become seven days for the pressurizer level instruments.

A 21 day extension would allow for a two week slip in the start of the outage. The pressurizer pressure instrument will require no extension for up to a three week slip in the outage schedule. Therefore, the staff has determined, and the licensee has agreed, that a three week extension of the pressurizer level instruments'is all that is required. The instruments in question are used for monitoring purposes only and initiate no automatic protective actions. The staff concludes that a three week, or approxi-mately 3%, extension of the surveillance interval for the pressurizer level instruments would not affect operability of those instruments. Any drift over that short time period would be expected to be small and not observable to the cperators. Since these instruments do not initiate any autortatic actions, the surveillance extension could not cause any setpoints to be exceeded.

For these reasons, the staff finds that the required extension would have no adverse effect upon public health and safety and is therefers acceptable.

In addition, the staff has concluded, and the licensee has agreed, that the approved extension should be located in SRs 4.3.3.5 and 4,3.3.6 for the remote shutdown monitoring and accident tunitoring instruments respectively. Consequently, those sections of the technical specifications will be revised and the new Specification 3/4.10.7 proposed by the licensees will not be required.

3.0 CONTACT WITH STATE OFFICIAL The NRC staff has advised the Chief of the Radiological Health Branch, State Department of Health Services, State of California, of the proposed determination of no significant hazards consideration.

No comments were received.

4.0 ENVIRONMENTAL CONSIDERATION

Pursuant to 10 CFR 51.21, 51.32 and 51.35, an environmental assessment and finding of no significant impact have been prepared and published (54FR35736) in the Federal Register on August 29, 1989. Based upon the environmental assessment, the Commission has determined that the issuance of the amendments will not have significant effect on the quality of the human environment.

y

5.0 CONCLUSION

i 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, (2) such activities will be conducted in compliance with the Commission's regulations and (3) the issuance of the amendments will not be inimical to the common defense and security or to the health and safety of the public.

Principal Contributor:

D. Hickman Dated:

August 30, 1989 l

_ - _.