ML17158C217
| ML17158C217 | |
| Person / Time | |
|---|---|
| Site: | Susquehanna  |
| Issue date: | 06/26/1997 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML17158C216 | List: |
| References | |
| NUDOCS 9707100207 | |
| Download: ML17158C217 (4) | |
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON~ 0 C 2055&4001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT N0.166TO FACILITY OPERATING LICENSE NO. NPF-14 ENDMENT NO. 140TO FACILITY OPERATI G LICENSE O.
NPF-22 PENNSYLVANIA POWER
& LIGHT COMPANY ALLEGHENY ELECTRIC COOPERATIVE INC.
. SUS UEHANNA STEAM ELECTRIC STATION UNITS 1
AND 2 DOCKET OS.
50-387 AND 388
- 1. 0 INTRODUCTION By letter dated June 10,
- 1996, as supplemented on July 25, 1996, the Pennsylvania Power and Light Company (the licensee) submitted a request for changes to the Susquehanna Steam Electric Station (SSES),
Units 1 and 2, Technical Specifications (TSs).
The requested changes would change the differential temperature Technical Specifications allowable values and trip setpoints for the reactor water cleanup system (RWCU) penetration room steam leak detection function.
2.0 DISCUSSION AND EVALUATION RWCU equipment spaces located outside the primary containment are provided with isolation instrumentation to detect reactor coolant piping breaks.
Several means of break detection are employed, one of which is the compartment high differential temperature function.
This instrumentation system senses the ventilation supply air temperature (cold leg) and exhaust air temperature (hot leg) to determine if a high differential temperature
- exists, an indication of steam discharge into the compartment airflow.
The RWCU compartment high temperature isolation function is not needed for reactor protection but is provided as a radiological protection feature.
Typically, the high differential temperature instruments are designed, and setpoints
- selected, to be capable of detecting the smallest possible leak without incurring spurious actuation due to the ventilation system and other transients.
For RWCU lines in RWCU compartments, a 25 gpm leak has historically been considered an appropriate heat source for use in analyses to determine the temperature difference to be sensed.
This specific leakage detection capability is specified in General Electric design specifications and accepted by the staff as a licensing basis requirement for SSES and similar facilities.
9707i00207 970626 PDR ADQCK OM00387 P
The licensee has experienced spurious RWCU isolations in the past, and as corrective action, requested instrument setpoint changes (approved in Amendments 123/90) and made ventilation system louver adjustments
(
Reference:
subject of violations 387/88-15-01 and 388/88-18-01).
To improve leakage detection system performance, an RWCU isolation system design basis and setpoint review was performed by the licensee to determine what should be the plant specific appropriate differential temperature instrument setpoints.
The review included a reanalysis of the temperature rise that would occur in the RWCU Pump
- Room, RWCU Heat Exchanger
- Room, and RWCU Penetration Room should a
25 gpm leak occur.
(These rooms are separate subcompartments of the contiguous RWCU Area, and are connected by open archways.)
The analysis was performed using the licensee's COTTAP (Compartment Transient Temperature Analysis Program)
- code, a thermal-hydraulic analysis code used by the licensee to analyze secondary containment pressure and temperature transients due to high energy line breaks and other events.
(A detailed description of the COTTAP code was published in "Nuclear Technology," April 1991.)
The licensee using COTTAP calculated the temperature rise of each subcompartment ventilation airflow resulting from a 25 gpm RWCU system line break.
Appropriate margins for drift and error were then applied to the delta-T to determine the proposed new TS limits.
Based on the licensee's reanalysis, the RWCU leakage detection
- system, using the proposed new setpoints developed in accordance with Regulatory Guide 1. 105, Revision 2 (1986), will be capable of initiating RWCU System isolation in the event of a 25 gpm line break.
Specifically in Table 3.2 of the TSs the following changes have been proposed:
The RWCU/Area Ventilation Delta Temperature - High trip setpoint has been changed to < 69 degrees F,
and the allowable value would be changed to < 72 degrees F..
With these
- changes, the level of sensitivity of the RWCU/Area Ventilation Delta Temperature will be consistent with the leakage detection system design basis and radiological dose analysis assumptions.
The proposed setpoint changes are therefore acceptable.
3.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Pennsylvania State official was notified of the proposed issuance of the amendments.
The State official had no comments.
- 4. 0 ENVIRONMENTAL CONSIDERATION The amendments change a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20.
The NRC 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 radiation
exposure.
The Commission has previously issued a proposed finding that the amendments involve'o significant hazards consideration, and there has been no public comment on such finding (61 FR 64389).
Accordingly, the amendments meet 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 the amendments.
5.0
~ON U
IGN 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 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:
W. Long Oate: June 26, 1997
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