ML20198F858
| ML20198F858 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 12/30/1997 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20198F854 | List: |
| References | |
| NUDOCS 9801120190 | |
| Download: ML20198F858 (3) | |
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UNITED STA1 ES s
j NUCLEAR REGULATORY COMMISSION t
WASHidQTON, D.C. 3068HOM SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NOS. 56 AND 42 TO FACILITY OPERATING LICENSE NOS. NPF-87 AND NPF-89 TEXAS UTILITIES ELECTRIC COMPANY COMANCHE PEAK STEAM ELECTRIC STATION. UNITS 1 AND 2 DOCKET NOS. 50-445 AND 50-446 1.0. INTRODUCTION By application dated July 9, 1996 (TXXX-96393), as supplemented on December 12, 199i (TXXX-97268), Texas Utilities Electric Company (TV Electric /the licensee) requested changes to the Technical Specifications (TSs)
(Appendix A to Facility Operating License Nos. NPF-87 and NPF-89) for the Comanche Peak Steam Electric Station (CPSES), Units 1 and 2.
These changes a) ply to CPSES Unit I only. The TS is a common document for both units, the c1anges to Unit 2 are only administrative.
The proposed changes would increase the minimum allowable value for the Steam Line Pressure -- Low.
The supplement contains clarifying information end does not change the staff's original proposed no significant hazards determination.
The affected TSs are Table 3.3-3, " Engineered Safety Features Actuation System Instrumentation Trip Setpoints." Specifically, the change increases the minimum allowable value from 593.5 psig to 594 psig for 1.e.1, Steam Line Pressure -- Low, Unit I for Functional Unit 1, Safety Injection; and 4.d.1, Steam Line Pressure -- Low, Unit I for Functional Unit 4, Steam Line Isolation.
2.0 BACKGROUND
The Steam Line Pressure -- Low and the Pressurizer Pressure -- Low setpoints i
for the Reactor Trip System (RPS) and the Engineered Safety Features Actuation System (ESFAS) at CPSES are monitored using Barton model 763 and 763A Gage Pressure Electronic Transmitters.
International Telephone and Telegraph Barton informed all industry users that they had identified an additional error in the transmitter's signal.
This error is incurred from the difference in temperature between the calibration and operational temperatures and impacts the setpoint calculations for the trip setpoints and allowable values for the aforementioned parameters.
The requested setpoint change in the TSs is requested to properly account for the additional error incurred by this temperature difference.
The changes are specific to Unit 1 and do not affect Unit 2 because Unit 2 uses Rosemount transmitters instead of Barton transmitters. Additic,r. ally, the changes are 9001120190 971230 PDR ADOCK 05000445 P
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'O 1-do not represent changes ir. the plant specific value changes and therefore,for Westinghouse Plants.
trcreved Standard Technical Specifications 3.0 NALuATIM The Steam Line Pressur6 -- Low allowable value is used to determine when a instrument channel has drifted beyond its expected range.
The trip setpoint is the nominal value used for calibrating a channel during a surveillance.
The allowable valut is the least conservative value allowed for the channel to still maintain operability in accordance with the assumptions in the accident
- analysis, j
I The steam Lir.e haure -- Low trip setpoint is used in two functional units The ESFAS is of the ESFt.5; Steam Line lsolation and Safety injection (SI)hannels in any one initiated when two of the three Steam Line Pressure -- Low c steam line decreases below the setpoint value. The ESFAS initiation of SI l
subsequently leads to the actuation of the RPS. Thus, the Steam Line Pressure
-- Low feeds into the control logic of both protection systems which protect and mitigate the reactor from damage during accident and transient scenarios.
the assumed setpoint value used for For the plant licensing accident analysis,is the least conservative value the Steam Line Pressure -- Low initiation l
possible to still mitigate the consequences of an accident.
For CPSES, the assumd accident analysis setpoint value is for the initiation of the ESFAS from the steam Line Pressure -- Low logic sequence.
Since the new allowable value of 5g4 peig for the Steam Line Pressure ~ Low setpoint is more
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conservative than the current allowable value of 5g3.5 psig and the assumed safety analysis limit value is not changed, the new allowable value is bounded by the previous analysis and does not increase the likelihood or consequences of an accident.
The setpoint methodology used for calculating the Steam Line Pressure -- Low-setpoint limits was not altered from the previous methodology used to determine the channel statistical allowance. The additional error incurred from the difference between the calibration temperature and the operational
. temperature is of comparable origins to the error incurred from the instrument teercrature sensitivity effects; therefore, the two-sensor temperature effects are added in percent span and included into the total channel statistical 1
allowance. This treatment and methodology are consistent with preytcusly submitted analysis using the Westinghouse methodology.
In summary, the inclusion of the additional temperature error ir the CdlCulation o7 the allowable value for the Steam Line Pressure -- Low setpoint does not impact the safety analysis of the plant.
The assumed accident analysis setpoint limit of 380 psig used in the safety analysis is not changed by the chw,e in the allowable value. Therefore, the new allowable value is bounded by the previous safety analysis. The methodology used to incorporate the additional error in the calculation is consistent with previously approved methodology and treats the error as a tepperature sensitivity error which is-a i
consistent statistical treatment.
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3-4.0 -STATE CONSULTATION In accordance with the Commission's regulations, the Texas State official was notified of the prepesed issuance of tae amendments. The State official had no comments.
5.0 [NVIR0lMENTAL CONSIDERATION The amendments chan e a requirement with respect to installation or use of a facility component ocated within the restricted area as defined in 10 CFR Part 20 The Nuclear Regulatory Commission 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 irdividual or cumulative occupational radiation expm ure. The Comission has previously issued a proposed finding that the oms:#dments 'nvolve no significant hazards consideration, and there has been no puFlic comment on such finding (62 FR 6579). Accordingly, the amendment' meet the eligibility criteria for categorical exclusion set forth i
Pursuant to 10 CFR 51.22(b) no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendments.
6.0 CONCLUS10$
The Commission 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 operation in the proposed manner, (2) such activities will be conducted in compliance with the Comuusion's regulations, defense) the issuance of the amendments will not be inimical to th and (3 and security or to the health and safety of the public.
Principal Contributor: Undine Shoop Date:
December 30, 1997
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