ML17164B054
| ML17164B054 | |
| Person / Time | |
|---|---|
| Site: | Susquehanna  |
| Issue date: | 05/25/1999 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML17164B053 | List: |
| References | |
| NUDOCS 9906020027 | |
| Download: ML17164B054 (3) | |
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UNITED STATES NUCLEAR REGULATORY COMMlSSION WASHINGTON, D.C. 20555-0001 SAFETY EVALUATIONBYTHE OFFICE OF NUCLEAR REACTOR REGULATION RELATEDTO AMENDMENTNO.
TO FACILITYOPERATING LICENSE NO. NPF-14 PP&L INC.
ALLEGHENYELECTRIC COOPERATIVE INC.
SUS UEHANNASTEAM ELECTRIC STATION UNIT 1 DOCKET NO. 50-387
1.0 INTRODUCTION
By letter dated March 12, 1999, PP&L, Inc., (PP&L, the licensee) submitted a request for changes to the Susquehanna Steam Electric Station, Unit 1, Technical Specifications (TSs).
The requested changes would change the allowable values for both the core spray (CS) system and the low pressure coolant injection (LPCI) system reactor steam dome pressure-low functions.
2.0 EVALUATION The existing Susquehanna Unit 1 TS Table 3.3.5.1-1 Core Spray System instrumentation item 1.c, "Reactor Steam Dome Pressure-Low (initiation)," and item 1.d, "Reactor Steam Dome Pressure-Low (injection permissive)," both have an existing ALLOWABLEVALUEof ~416 psig. Likewise, LPCI System instrumentation item 2.c, "Reactor Steam Dome Pressure-Low (initiation)," and item 2.d, "Reactor Steam Dome Pressure-Low (injection permissive)," have an ALLOWABLEVALUEof >416 psig. The proposed revised allowable VALUEwould have a range of ">407psig and ~433psig" for functions 1.c, 1.d, 2.c, and 2.d. The licensee stated that the revised setpoint and allowable values were determined based on guidance in General Electric (GE) Topical Report NEDC-31336, "General Electric Instrument Setpoint Methodology" and details for these values are documented in PP&L calculations.
The CS system and the LPCI system are designed to inject water into the reactor vessel to cool the core during a LOCA event. The CS and LPCI injection valves open when reactor pressure drops below the reactor vessel low pressure permissive.
The upper analytical limitfor the permissive is the CS system and the LPCI system's maximum design pressure. The lower analytical limitis the lowest pressure which allows injection to prevent exceeding the fuel cladding temperature limit. The proposed new allowable values were selected to lie within the upper and lower analytical limits as defined in the Susquehanna Final safety Analysis Report (FSAR) accident analyses.
These new values do not affect the LOCA or its "limitingfault" frequency of occurrence and do not introduce any new accidents or malfunctions of equipment important to safety.
The new allowable values also do not change the logic or function of the reactor vessel low pressure permissive.
9906020027 9"70525 PDR ADQCK 05000387 P
PDR The CS system and LPCI system initiation logic has a low pressure permissive function which prevents the CS system injection valves HV-152-F005A/B and the LPCI system injection valves HV-151-F017A/B from opening until reactor pressure has decreased to the system's design pressure.
The purpose of this permissive is to prevent CS system and LPCI system over pressurization and prevent fuel clad temperature limits from being exceeded.
The permissive signals are initiated from pressure instruments that sense reactor steam dome pressure.
The existing Susquehanna Unit 1 TS specifies only a lower allowable value which is based on the analytical limitin FSAR Table 6.3-2 (400 psig) intended to protect against exceeding the peak fuel cladding temperature.
The existing TS does not specify an upper allowable value for piping over pressurization protection design limits specified in FSAR Section 6.3.2 for the CS system and LPCI system.
These piping design limits form the basis for the upper analytical limit. Currently, the upper allowable value is controlled by surveillance procedures.
Establishing the new upper allowable value for this function in the TS is conservative, and the staff finds this acceptable.
The staff had a concern regarding potential interactions between the setpoint and each allowable value and the method that verified instrument operability during instrument surveillance tests to demonstrate that the setpoint calculation uncertainty assumptions are being satisfied.
In response to the staff's concern, the licensee noted that the instrumentation and control system surveillance procedures verify that the pressure switch actuates on decreasing test pressure within the required tolerance bands specified by the setpoint calculations.
These tolerance bands are specified in the procedure as part of the acceptance criteria for the operation of the switches and the relay logic. Control room annunciation and actuation of the appropriate relays in the relay room are also monitored as part of the surveillance.
The licensee has indicated that the surveillance procedures will be updated to incorporate the new setpoint and allowable values for the CS and LPCI systems reactor steam dome pressure-low function provided by the setpoint calculations.
The staff find this acceptable.
Based on a review of the licensee's safety analysis, the staff concludes that the proposed TS changes provide for sufficient margins between safety limits and operating setpoints, and the licensee's setpoint methodology for establishing the revised TS allowable values is consistent with the approved instrument setpoint methodology in GE topical report NEDC-31336. The staff concludes, therefore, that the proposed TS changes are acceptable.
3.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Pennsylvania State officialwas notified of the proposed issuance of the amendment.
The State official had no comments.
4.0 ENVIRONMENTALCONSIDERATION The amendment changes 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
'etermined 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 the amendment involves no significant hazards consideration, and there has been no public comment on such finding (64 FR 17028). Accordingly, the amendment meets the eligibilitycriteria 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 amendment.
5.0 CONCLUSION
The Commission has concluded, based on the considerations discussed above, that: (1) there is reasonable assurance that the health and safety of the public willnot 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 amendment will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributors:
V. Nerses Date:
May 25, 1999