ML20248B082
| ML20248B082 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 05/26/1998 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20248B080 | List: |
| References | |
| NUDOCS 9806010175 | |
| Download: ML20248B082 (3) | |
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8 UNITED STATES NUCLEAR REGULATORY COMMISSION
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WASHINGTON, D.C. SDespect SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 159 TO FACILITY OPERATING LICENSE NO. NPF-49 j
NORTHEAST NUCLEAR ENERGY COMPANY. ET AL.
MILLSTONE NUCLEAR POWER STATION. UNIT NO. 3 DOCKET NO. 50-423 1
1.0 INTRODUCTION
l By letter dated October 15,199'/, as supplemented January 23 and April 8,1998, the Northeast l
Nuclear Energy Company, et al. (the licensee), submitted a request for changes to the Millstone Nuclear Power Station, Unit No. 3 Technical Specifications (TS). The requested changes would revise the action statements and the instrumentation trip setpoint tables in the TS for the reactor trip system (RTS) and engineered safety feature actuation system (ESFAS) instrumentation. In addition, the amendment (1) decreases the reactor trip setpoint for the reactor coolant pump (RCP) low shaft speed (underspeed trip setpoint) from 95.8 percent to 92.4 percent of rated speed, (2) makes editorial changes, and (3) changes the Bases to reflect the new methodology.
The January 23 and April C,1998, letters provided clarifying information that did not change the initial proposed no significant hazards consideration determination.
2.0 EVALUATION The current Millstone Unit 3 TS requirement provides a Limiting Condition for Operation (LCO) option when an RTS or an ESFAS instrumentation channel trip setpoint is found less conservative than its allowable value (AV). The option allows the licensee to either adjust the trip setpoint consistent with the TS value and within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> conduct a calculation to demonstrate satisfaction of an equation justifying operability for the affected channel or declare the channel l
inoperable. The proposed change would remove the option of the calculation and require the operator to declare the instrumentation channel inoperable when its setpoint is found less conservative than the AV. The TS Bases states that the specified AV defines the limit beyond which an instrumentation channelis to be considered inoperable. Therefore, the proposed TS change is conservative with respect to the current requirement and is consistent with the i
l Westinghouse Standard TS (NUREG-1431, Rev.1). The staff, therefore, finds the proposed i
change acceptable.
l The proposed TS change to two columns from five columns retains the AV and the trip setpoint with the trip setpoint relabeled " Nominal Trip Setpoint"(NTS). Each instrument will have a two-sided (t) calibration tolerance band around the NTS, which will be controlled by plant procedures. The TS flases defines calibration tolerance as the numerical difference between the AV and the NTS. The TS Bases further states that an instrumentation channel is considered i
operable and its trip setpoint consistent with the NTS when the process rack bistable setting is 9806010175 990526 PDR ADOCK 05000423 p
PDR l
b e procedures. The TS Bases defines calibration tolerance as the numerical difference between the AV and the NTS. The TS Bases further states that an instrumentation channel is considered operable and its trip setpoint consistent with the NTS when the process rack bistable setting is measured within the "as left ' calibration tolerance. The staff finds the licensee's proposal to retain the above described two columns in the Millstone Unit 3 TS consistent with NUREG-1431, Rev.1 and, therefore, acceptable.
The three columns eliminated from the TS were those parameters used in the equation to establish channel operability in case the instrumentation channel exceeded its AV. These additional columns included those values that could be used to demonstrate that a channel was still operable, even though the AV had been exceeded, thus, reducing the likelihood of the need for issuance of a licensee event report (LER) under the requiremems of 10 CFR 50.73.
However, a subsequent revision of 10 CFR 50.73 changed the reporting requirements for LERs, such that the events reported were only those where the plant experienced loss of an instrument function, and not just a single inoperable instrumentation channel. Further, the option of performing an operability demonstration calculation was removed from the Westinghouse Standard TS. Therefore, there was no longer any benefit to the five-column format for instrument setpoints. The staff finds the licensee's proposal to remove the three additional columns from the Millstone Unit 3 TS acceptable.
The proposed AV changes for all process instrumentation channel setpoints in the RTS and ESFAS based on revised engineering calculations. These AV changes were established in accordance with a previously approved setpoint methodology. The staff finds these changes conservative and, therefore, acceptable The licensee proposed changing the RCP low shaft speed trip setpoint from 95.8 percent to 92.4 percent rated normal speed. The licensee stated that the change will not change the probability of occurrence or consequences of a loss of forced reactor coolant flow event and the existing accident analysis remains valid. The licensee further stated that the change was being made to decrease the incidence of inadvertent tripping caused by transient power line frequency variations. The staff finds the change acceptable. The licensee nas also proposed several editorial changes that the staff finds acceptable.
Based on the review of the licensee's October 15,1997, and January 23 and April 8,1998, submittals, the staff concludes that the proposed TS changes are consistent with the guidelines of NUREG-1431 and approved setpoint methodology. Therefore, the proposed change are acceptable.
3.0 STATE CONSULTATION
in accordance with the Commission's regulations, the Connecticut State official was notified of the proposed issuance of the amendment. The State official had no comments.
4.0 ENVIRONMENTAL CONSIDERATION
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
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e 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 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 (62 FR 61842 dated November 19,1997). Accordingly, the amendment meets 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 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 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 amendment will not be ir.!mical to the common defense and security or to the health and safety of the public.
Principal Contributor: 1. Ahmed Date:
May 26, 1998 1E