ML20070M791
| ML20070M791 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 03/18/1991 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20070M785 | List: |
| References | |
| NUDOCS 9103220008 | |
| Download: ML20070M791 (2) | |
Text
_ _ _ _ _ _ _ _ __ _ _ _ _
gm ef '
o UNITED STATES g
E NUCLE AR REGULATORY COMMISSION 3
e l
wAsmotow. p. c. rosss t
s 5.,3..../
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION R, ELATED TO AMENDMENT NO. 38 TO FACILITY OPERATING LICENSE NPF-68 AND AMENDMENT NO. 18 TO FACILITY OPERATING LICENSE NPF-81 GEORGIA POWER COMPANY, ET AL.
V0GTLE ELECTRIC GENERATING PLANT, UNITS 1 AND 2 DOCKET N05. 50-424 AND 50-425
1.0 INTRODUCTION
By letter dated May 8, 1989, Georgia Power Company, et al. (the licensee) proposed licensing amendments to change the Technical Specifications (TSs) for Vogtle Electric Generating Plant (VEGP or the facility), Units 1 and 2.
The proposed change would revise three of the five values specified for item 1.d.
" Pressurizer Pressure--Low," in TS Table 3.3.-3, " Engineered Safety Features Actuation System Instrumentation Trip Setpoints." Specifically the value for total allowance (TA) would change from 13.1 to 21.25; the value for the statistical summation of errors assumed in the safety analyses (Z) would change from 10.71 to 18.36; and the specified allowable value would change from 2 1860 psig to 2 1856 psig.
The proposed amendments would not change the values specified for trip setpoint (k 1870 psig) and sensor error (1.67).
2.0 BACKGROUND
In 1986, the licensee discovered that the uncertainties due to temperature compensation for transmitters supplied by Veritrak/ lobar were greater than the instrumentation uncertainties that had been assumed in the safety analyses.
Consequently, the Unit 1 TS was changed to add a footnote to revise the trip setpoint for Low Pressurizer Pressure Safety Injection.
Westinghouse conducted evaluations that ac. counted for the increased uncertainty associated with temperature compensation for the Veritrak/Tobar transmitters.
Based on these evaluations, the footnote was omitted when the combined TSs for Units 1 and 2 were issued in March 1989.
The evaluations by Westinghouse included an increased statistical summation of errors and a lower safety analysis limit.
This included evaluating the increase in the difference between the s'aecified trip setpoint and the value used in the enalysis for the trip setpoint.
The licensee notes that the evaluations deaonstrated additional margin between the trip setpoint and the ellowable value which will reduce the possibility of instrument setpoint drift resulting in the instrument being declared inoperable.
The proposed changes to TS Table 3.3.-3 for TA, Z, and Allowable Value are intended to make the TSs consistent with parameters used in these evaluations.
9103220000 910310 ADDCK 050 4
gDR
y 3.0 EVALUAT10h The Final Saf ety Analysis Report for the f acility, as updated March 1990, provides additional information on the Veritrak/Tobar pressure transmitters.
Tables 7.3.1 4, ' Primary System Accidents and Required Instrumentation" and 7.3.1-5, " Secondary System Accidents and Required Instrumentation" list the accuracy of instrumentation fer pressurizer pressure as i 1.75 percent of the instrument span.
The range is from 1700 psig to 2500 psig, corresponding to a span of 800 psi and an accuracy of 1 14 psi.
This agrees with the requested cht.nge in allowable values the difference between the trip setpoint (1670 psig) and the proposed allowable value (1856 psig) is 14 psi.
The licensee notes that safety analyses performed for them by Westinghouse to account for additional uncertainty in the Veritrak/Tobar instrument due to temperature compensation demonstrate the proposed values of TA, Z, and Allowable Value to t,e acceptable. The analyses did not change the trip setpoint and showed the reviseo analyses limits to be bounded by the existing analyses. The NRC has considered the change in the safety analyses limits and finds them acceptable in evaluations performed for the licensee. Moreover, although the proposed allowable value is less than the current allowable value, it is consistent with instrument accuracy and safety analyses, and is, therefore, acceptable.
4.0 ENVIRONMENTAL CONSIDERATION
The amendments involve changes in requirements with respect to the installation or use of facility components located within the restricted area as defined in 10 CFR Part 20.
The staff has determined that the amendments involve 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 Commission's staff has previously issued proposed finding that the amendments involve no significant hazards consideration, and there has been no public coment on such finding. Accordingly, the amendments meet 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 these amendments.
4.0 CONCLU3 ION Ne Comission's proposed determination that the amendments involve no significant hazards consideration was published in the Federal Register (54 FR 31108) on July 26, 1989. The Comission consulted with the State of Georgia. No public comments were received, and the State of Georgia did not have any coments.
The staff has concluded, based on the considerations discussed above, that (1) endangered by operation in the proposed manner, and (2)y of the public will not be there is reasonable assurance that the health and safet l
I such activities will be conducted in compliance with the Comission's regulations, and the issuance of these amendments will not be inimical to the comon defense and security or to the health and safety of the public.
Principal Contributor:
D. Hood, P0!l-3/DRPE P. Loeser, SICB/ DST R. Jones, SRXB/ DST Dated:
March 18, 1991