ML20034A038
| ML20034A038 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 04/03/1990 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20034A033 | List: |
| References | |
| NUDOCS 9004190213 | |
| Download: ML20034A038 (2) | |
Text
-
t
((ecio
+
o UNITED STATES
'g NUCLEAR REGULATORY COMMISSION 3.c.
r.
l wAssiwoTow.D.c rosss
\\*...*/
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION i
RELATED TO AMENDMENT NO.13 TO FACILITY OPERATING LICENSE NO. NPF-76, HOUSTON LIGHTING & POWER COMPANY CITY PUBLIC SERVICE BOARr_OF SAN ANTONIO CENTRAL POWER AND L1,GHT COMPANY CITY OF AUSTIN. TEXM j
DOCKET NO. 50-498 l
SOUTH TEXAS PROJECT,- UNIT 1 i
i
1.0 INTRODUCTION
By application dated January 25, 1989, Houston Lighting & Power Comnany, et. al., (the 'sicensee) requested changes to the Technical Specifications (TS) (Appendix A to Facility Operating License No. NPF-76) for South Texas Project, Unit 1.
The proposed changes would modify the calibration requirements for the source range neutron monitors to allow for the possible installation of a replacement low noise preamplifier in the i
instrumentation circuitry.
2.0 DISCUSS 10H With present circuitry the chanr.el calibration specified in TS Table i
4.2-1 requires the development of high voltage plateau curves for each of the BF proportional counters detector degradation. Upon replacement witht$elow.noisepreamplifier,thisTSrequirementwillbeaccomplished by varying discriminator bias over a specified range of applied detector high voltages and the recording of changes in the neutron count rate.
A graph of count rate versus discriminator bias is then generated for which-the bias operating point is then selected. Detector degradation is determined by downward deviation in the discriminator bias curve from that j
of previous curves.
3.0 EVALUATION 1
DuringthepreoperationaltestingofSouthTexasProject(STP) Unit 2, two of source range neutron monitor preamplifiers failed their performance testing and required replacement.. At that time.all of the original design preamplifiers, which are the model presently installed in STP Unit 1, were replaced with a new low noise preamplifier that the i
manufacturer provided as a direct replacenent and which had a reduced F
susceptibility to electromagnetic interference. This preamplifier replacement fulfilled a licensing commitment for STP Unit 2.
l 9604190213 9004o3 PDR ADOCK 05000498 P
2 The NRC staff had previously concluded for STP Unit 2 that both methods of channel calibration for periodical assessment of the condition of the source range neutron detectors are acceptable (Section 7.2.2.5 of NUREG-0781, Supplement 6, safety Evaluation of the operation of Soutb Texas Project Unit 2). The proposed channel calibration requirements for STP Unit I are the same as that previously approved for Unit 2.
Thus, the staff likewise finds the incorporation of these alternate requirements to be similarly acceptable.
4.0 ENVIRONMENTAL CONSIDERATION
The amendment involves a change in a requirement with respect 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.
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 exposures.
The Cormission has previously. issued a proposed finding that the amendment involves no significant hazards consideration and there has been no sublic comment on such finding. Accordingly, the. amendment meets the eligi>ility criteria for categorical exclusion set forth in 10 CFR Section 51.22(c)(9).
Pursuant to 10 CFR 51.22(b), no environmental impact statement or environ-mental assessment need be prepared in connection with the issuance of the amendment.
5.0 LONCLUS1011 Besed upon its evaluation of the proposed changes to the South Texas Project, Unit 1 Technical Specifications, the ',,taff has concluded that:
there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and such activities will be conducted in compliance with the Commission's regula-tions and the issuance of the amendment will not be inimical to the comon defense and security or to the health and safety of the public. The i
staff, therefore, concludes that the proposed changes are acceptable.
Date: April 3,1990 Principal Contributor:
P. Milano, NRR/DRSP
,