ML20211P473
| ML20211P473 | |
| Person / Time | |
|---|---|
| Site: | Hatch  |
| Issue date: | 10/08/1997 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20211P467 | List: |
| References | |
| NUDOCS 9710200204 | |
| Download: ML20211P473 (4) | |
Text
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NUCLEAR REGULATORY CSMMISSl2N
{%,...../j wAswiwotow. o.c. sensusot SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.210TO FACILITY OPERATING LICENSE DPR.57 4
AMD AMFNDMENT NO.iB1TO FACILITY OPERATING LICENSE NPF:5 SOUTHERN NUCLEAR OPERATING COMPANY. INC.. ET &
EDWIN l. HATCH NUCLEAR PLANT UNITS 1 AND 2 DOCKET NOS. 50 321 AND B0 366
1.0 INTRODUCTION
By letter dated May 9,1997, as supplemented September 3,1997, Southern Nuclear Operating Company, Inc. (Southern Nuclear), et al. (SNC or the licensee) proposed license amendments to change the Technical Specifications (TS) for the Edwin 1. Hatch Nuclear Plant (Plant Hatch), Units 1 and 2.
The proposed changes would revise the applicability requirements for the Rod Block Monitor (RBM) to require that the RBM be operable whenever reactor thermal power is greater than or equal to 29 percent of rated thermal power (RTP). The changes modify TS Table 3.3.2.1 1, to revise the operability requirements for the RBM system. These modifications are more restr!ctive than current TS requirements and restore the RBM operability requirements to the requirements that existed pric' to Amendment Nos.105 and 39 for Plant Hatch, Units 1 and 2, respectively.
SNC installed the General Electric (GE) average power range monitor rod block Technical Specification anticipatory reactor trip system (ARTS) revisions to the RBM for both units of Plant Hatch. The ARTS program included a revision to the RBM Applicability section in TS Table 3.3.2.1 1. The amendments, therefore, modify the RBM operability requirements in Table 3.3.2.1 1 and also delete the requirements in TS Section 5.6.5 to report RBM operability requirements in the cycle specific Core Operat'c3 Limits Report (COLR). The September 3,1997, supplemental letter provided clarifying information that did not change the initial proposed no significant hazards consideration determination.
2.0 EVALUATION The design basis of the RBM is to mitigate the consequences of the Rod Withdrawal Error (RWE) event at power. The analysis of the RWE requires a determination that appropriate fuel thermal limits (maximum critical power ratio (MCPR), mechanical overpower (MOP),
thermal overpower (TOP)) are not exceeded for the RWE. Operation with the revised ARTS RBM TS operability statement was approved by the NRC in December 1994 for Plant Hatch, Units 1 and 2 (References 1 and 2). The MCPR limits incorporated into the Plant Hatch RBM operability statement with the ARTS changes were determined from a generic RWE analysis documented in NEDC 30474 P (Reference 3). The limits were developed to assure that the complete withdrawal of any single rod would not violate the Safety Limit MCPR.
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2 The RWE analysis is performed for each cycle using the NRC approved methods described in GESTAR 11 (Reference 4). This analysis showed that the MOP and TOP requirements would be met without tal he credit for en RBM control rod block. GE recently informed SNC that it was necessary to take credit for RBM high trip setpoint to meet the MOP (fuel i
cladding not to exceed 1 percent plastic strain during a RWE) requirements. This RBM restriction was needed at power levels above 29 percent of RTP Currently, the TS allow the RBM to be inoperable when the core power is greater than 90 percent of rated power and the MCPR is greater than 1.40. The more restrictive condition of requiring RBM operability for all operation above 29 percent RTP is being r64uested in order to ensure that the RBM T3 requirements will be adequate in the future without tellence on additional cycle specific requirements being included in the COLM In response to a staff request, the licensee provided assurance, in a supplomontal letter dated September 3,1997, that it will confirm that the RBM TS requirements continue to be valid at every operating cycle.
Below 29 percent RTP, it is assumed fuel damage cannot occur for any single rod withdrawal. By the September 3,1997, letter, the licensee also provided additional assurance, in response to a staff request, that fuel damage cannot occur for any RWE events below 29 percent power. Therefore, requiring the RBM to be operable below 29
- percent RTP is not necessary. On this basis, the changes are acceptable.
Subsequent to the installation of ARTS at Plant Hatch, the NRC approved the replacement of cycle specific power distribution limits in the TS with a reference to the COLR (Reference 5). At that time, the MCPR requirements for the RBM operability were removed from the TS and placed in Section 2 of the COLM. When the improved TS were implemented at Plant Hatch, Units 1 and 2,la March 1995, the RBM operability requirements were added back into the TS, out were not removed from the COLM Section 5.6.5 of the TS is being revised to delete the RBM operability requirements from the COLR. This change is acceptable, in conclusion, the staff finds the licensee's request for changes to the Plant Hatch, Units 1 and 2, Technical Specifications to require that the Rod Block Monitor be operable whenever reactor thermal power is greater than or equal to 29 percent of rated thermal power acceptable. This change is more restrictive than current Technical Specification requirements and restores the RBM operability requirements to the requirements that existed prior to Amendment Nos.105 and 39 for Units 1 and 2, respectively. Requiring both channels of the RBM to be operable for all operations above 29 percent power bounds all conditions for which a rod withdrawal error may cause fuel thermal limits to be
- exceeded. - Below 29 percent RTP, fuel damage cannot occur for any rod withdrawal event. Therefore, requiring the RBM to be operable below 29 percent RTP is not necessary. The Bases have also been modified consistaat with TS changes. Accordingly, the amendments are acceptable.
3.0 STATE CONSULTATION
in accordance with the Commission's regulations, the Georgia State official was notified of the proposed issuance of the amendments. The State official had no comments.
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4.0 ENVIRONMENTAL CONSIDERATION
The amendments change a requirement with respect to the installation ct use of facility -
components located within the restricted area es defined in 10 CFR Part 20 and changes surveillance requirements. 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 lasued a i
proposed finding that the amendments involve no significant hazards consideration, and there has been no public comment on such finding (62 FR 40857 dated July 30,1997).
Accordingly, the amendments meet the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9). Pursuant to 10 CFR 51.:;2(b) no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the
- amendments.
5.0 CONCLUSION
The Commission has concluded, based on the cormiderations 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 cor. ducted 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.
l Principal Contributor: Ron Frohm, Sr.
Date:
October 8, 1997 f
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4 REFERENCES 1.
NRC letter issuing Amendment No.105 to Facility Operating Licerise No. DPR 57 for Edwin 1. Hatch Nuclear Plant, Unit 1, R.A. Hermann to J. T. Beckham, December 31,1984.
l 2.
NRC letter issuing Amendment No. 39 to Facility Operating License No.
NPF 5 for Edwin 1. Hatch Nuclear Plant, Unit 2, G. W. Rivenbark to J. T. Becktum, July 31,1984.
3.
NEDC 30474 P, " General Electric BWR Licensing Report: Average Power Range Monitor, Rod Block Monitor and Technical Specification improvement (ARTS) Program for Edwin 1. Hatch Nuclear Plant Units 1 l
and 2,* December 1983.
4.
NEDE 24011 P A 13, General Electric Standard Application for Reactor Fuel (GESTAR II)," August 1996.
5.
NRC letter issuing Amendment Nos.168 and 106 to Facility Operating Licenses DPR 57 an(J NPF 5 for Edwin 1. Hatch Nuclear Plant, Units 1 and 2. L.P. Crocker to W.G. Harlston, lil, December 29,1989.
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