ML20154Q988

Safety Evaluation Supporting Amend 1 to License NPF-56

ML20154Q988
Person / Time
Site:	Seabrook
Issue date:	09/27/1988
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20154Q757	List: ML20154Q754 ML20154Q887 ML20154Q988
References
NUDOCS 8810040123
Download: ML20154Q988 (3)

Text

_ _ _ - _ _ -

g .

i ,

d#pa hvowe, ',

UNITSJ STATss l' ., e NUCLEAR REGULATORY COMMISSION a

$. l M86468eoT086. o. c. Neet J

,e '

5 , *-

5AFETY EVALUAT!0M BY THE OFFICC OF NUCLEAR REACTOR R,EGULAT!0N SUPPORT!NG AMENDMENT NO. 1 TO FACILITY OPERATING LICENSE NO. Npr.5,6 PUBLIC SERVICE CONdANY OF NEW HAMPSHIRE SEABROOK STATION. UNIT 1 DOCKET N0, 50 443

1.0 INTRODUCTION

/BACKGROUWD l On July 8,1988. Public Service Company of New Hampshire (?$NH) requested an i 1

amendment to the Technical Specifications for Seabrook Station. Unit 1 to j 4

change the letpoints for the pressurizer pressure, pressurizer water j level, and steam generator water level channels as a result of replacing q the Veritrak/Tobar transmitters with Rosemount transmitters. This i request was supplemented by PShH's submittal of August 8.1988. l In early 1986 PSNH reported an excessive change in Veritrak transmitter accuracy as the ambient temperature changed from 80 to 130 degrees F. l The transmitters in cuestion, which provice inputs to the Reactor l Protection System (RPS) were returned to Westinghouse for analysis and  ;

I repair. Subsequent testing by West ".ghouse on a lar Veritrak units supp1ted by Tobar (forwerly Veritrak)ger sample of 1

demonstrated calibration shifts in excess of manufacturer e,ecified limits when the ambient temperature was varied from 50 to 320 degrees F. It was .

determined that these excessive chLnges observed in Veritrak transmitter  :

accuracy as the ambient temperature changed could create a condition that '

could violate allowable technical specification limits.

) Based on the test results from Westinghouse and available data on Varitrak/Tobar transmitters, the licensee increased the survetil:nce and calibration requirements for sintlar type class it units located inside i containment which provide inputs to the RP$. Additionally. Westinghouse i recce ended that the licensee revise the trip setpoints for pressurizer l

! low pressure and steam generator low-low level reactor tries. The l Seabrook Technical Specifications now refle:t these revised setpoints. '

I

! Eecause the increase in surveillance and calibration requirements l lergthen the time the plant will need to reeain in Mode 3 during startup l 4

and add to the workload of the station staff and because the existing .

l Technical Specification setpoint? have less margin to the operating range  ;

and thus increase ti.e chance of unnecessary reactor trips, the licensee  ;

has decided to replace the effected transmitters with Rosemount i 1 transmitters to allow the additional surveillance and cr.libration i j requirerents to be deleted and the setpoints relaxed. [

I

! 8910040123 000927 j j DR ADOCK 050 4j3 L

i ,

i 2

2.0 , EVALUATION As stated above, the Veritrak/Tobar transmitters experienced temperature compensation shifts in excess of their specified values; therefore, the calibration frequency of the transmitters was increased and the trip setpoints were revised and set n, ore conservatively. This results in an increase in the probability of unnecessary plant trips.

The Rosemount transmitters replace the Verit.ak/Tobar Class 1E transmitters that provide steam generator level, oressurizer level and pressurizer / pressure inputs to the SSPS. The licensee has determined that the replacement Rosemount transmitters are being used extensively in other operating nuclear power plants and have a proven history of successful operation while performing within stated accuracy limits.

Also, these Rosemount transmitters are environmentally and seismically qualified for their locations inside containment at Seabrook Station.

The staff review and evaluation of the technical specification changes reflecting the above replacement transmitters and the reasons for rsquesting these changes has led to the conclusion that the proposed changes will not:

1. Significantly increase the probability or consequences of any accident previously evaluated. The basis for tais determination is: (1) the replacement Rosemount transmitters are environmentally and seismically qualified for the service intended. (2) these replacement units have a proven history of successful operation under similar applications at other nuclear power plants, and (3) the protection system setpoints were developed by calculating the instrument channel statistical allowance using the previously NRC approved Westinghouse methodology and applying this to the FSAR Chapter 15 accident analysis P.mit.

2. Involve a significant reduction in a margin of safety at the Seabrook Station. For example, the licensee submittal of July 8.

1988 shows that when compared to the calculated values, the steam generator low-low level setpoint is conservative and the margin between the total allowance and the channel statistical allowance is increased for this replacement transmitter application. This is also the case when comparing the calculated values to the low l pressurizer pressure reactor trip setpoint, the low pressurizer pressure safety injection setpoint, and the high pressurizer pressure reactor trip setpoint.

To sumarize, the proposed change provides new values for Total Allowance (TA). Statistical Sunnation of Errors (Z). Trip Setpoint, and Allowable Value for the replacement transmitters in the Seabrook Technical Spe:ification Tables 2.2-1 (Reactor Trip System Instrumentation Setpoints) and 3.3-4 (Engineered Safety Features Actuation System Instrumentation Setpoints). The steam generator water level low-low value is also revised in Specification 4.4.1.2.2. 4.4.1.3.2 and 3.4.1.4.1. to be consistent with the setpoints.

l

,- , - - w

3 The staff has reviewed the pages of the Seabrook Station Technical Spec 4fications which are being revised to reflect the proposed changes as discussed herein and the reasons given for requestirig these changes as presented in Enclosure 2 to the licensee'; submittal datec July 8, 1988.

Based on this review the staff believes that the proposed changes meet tne requirements and follow the guidelines as shown in the Standard Review Plan for instrumentation asecciated with the RPS and the associated safety limits present in Chapter 15 of the Seabrook Station FSAR. Therefore, the proposed changes, as stated, are acceptable.

3.0 ENVIRONMENTAL CONSIDERATION

' is amendment involves a change in the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20.

The staff has determined that the amendment involves 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 radiation exposure. The Commission has previously issued a proposed finding that this amendment involves no significant hazards consideration and there has been no public comment on such finding. Accordingly, this amendment meets the eligibility criteria for categorical 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 this amendment.

4.0 CONCLUS!0N The staff has evaluated the licensee's request to revise the Technical Specifications to change the technical specification setpoints for the pressurizer pressure, pressurizer water level, and steam generator WPter level channels as a result of replacing the Veritrak/Tobar transmitters with Rosemount transmitters.

The staff has 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 cperation in the proposed manner, and (2) such activities will be conducted in compliance with the Commission's regulations and the issuance of this amendment will net be inimical to the conron defense and security nor to the health and safety of the public.

Principal Contributors: Vincent D. Thomas and Conald S. Brinkman Dated: September 27, 1988 l

__ , _ . , , _ _ _ . _ _ . - _ . -