ML20246L320
| ML20246L320 | |
| Person / Time | |
|---|---|
| Site: | Salem  |
| Issue date: | 05/09/1989 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20246L318 | List: |
| References | |
| NUDOCS 8905180294 | |
| Download: ML20246L320 (6) | |
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,9 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT N05. 96 AND 72 TO FACILITY OPERATING LICENSE NOS. OPR-70 AND DPR-75 PUBLIC SERVICE ELECTRIC & GAS COMPANY PHILADELPHIA ELECTRIC' COMPANY DELMARVAPOWfRANDLIGHTCOMPANY ATLANTIC CITY ELECTRIC COMPANY SALEM GENERATING STATION, UNIT NOS. 1 Atm,2_
DOCKET N05. 50-272 AND 50-311
1.0 INTRODUCTION
By letter dated December 30, 1988, and supplemented by letters dated April 19 and May 4,1989, Public Service Electric & Gas Company requested' an amendment to Facility Operating License Nos. DPR-70 and DPR-75 for the Salem Generating Station, Unit Nos. I and 2.
The supplemental letters provided corrected technical specification paces which did not change the technical requirements and a connitment to revise FSAR Section 15.4.5.
The suppler, ental letters did not affect the action as noticed in the Federal Register or alter the staff's initial determination.
The licensee's request was for the Technical Specification changes resulting from the use of VANTAGE 5 Hybrid (VANTAGE SH) fuel assemblies for Salem Unit 1 Cycle 9 and Unit 2 Cycle 6 reload core and future cores. The VANTAGE SH fuel desig{STD) fuel assembly designs.n evolves from the VANTAG (0FA),andStandard The features of the VANTAGE SH fuel assembly consist of reconstitutable top nozzles, Zircaloy grids, Debris Filter Bottom Nozzles (DFBNs), and the capability of achieving high burnups. These features were previously reviewed and approved by NRC in the Westinghouse topical report WCAP-10444-P-A,
- Referenced Core Report VANTAiE 5 Fuel Assembly" Addendum 2.
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The licensee also plans to remove thimble plugging devices from the Salem to o cores. Thimble plugging devices are used in Salem Units to limit the 88 bypass flow. These fuel assembly guide thimble tubes that are not in 00 0 RCCA locations or are not equipped with sources or burnable absorbers g
have thimble plugs inserted in them.
SO During the review of VANTAGE 5 fuel design in WCAP-10444-P-A, we "P
identified a few conditions to be resolved for those licensees using I
L VANTAGE 5 fuel design. Since the VANTAGE SH fuel design adopts some features from the VANTAGE 5 fuel design, our review and evaluation will Sa
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address those conditions listed in the safety evaluation of WCAP-10444-P-A that affect Salem's VANTAGE SH fuel.
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.. - 2.0 EVALVATION (1) Statistical Convolution Method In our SER on WCAP-10444, we stated that the statistical convolution method should not be used in VANTAGE 5 for evaluating the fuel rod shoulder gap.
The licensee indicated that the statistical convolution method was not used for the VANTAGE 5H fuel design and the currently approved method was used for evaluating fuel rod shoulder gap. Therefore we consider this acceptable.
(2) Irradiation Demonstration Program In our SER on WCAP-10444, we required that an irradiation program be performed to confirm the VANTAGE 5 fuel performance.
The licensee stated that there were numerous demonstration programs involving 0FA fuel assemblies containing Zircaloy grids irradiated in 14X14,15X15 and 17X17
- cores, The satisfactory performance of these demonstration assemblies resulted in OFA with Zircaloy grids in reload applications in many Westinghouse reactors.
The 0FA fuel assemblies with Zircaloy grids cover the VANTAGE SH fuel design feattaes; we thus conclude that the VANTAGE SH fuel assemblies will perform satisfactorily in Salem.
(3) Improved Thermal Design Procedure (ITDP)
In our SER on WCAP-10444, we stated that those restrictions in approving the use of Westinghouse improved thermal design procedure (ITOP) should be applied to the VANTAGE 5 fuel design.
The licensee indicated that they conformed to these restrictions of ITDP for Salem.
We therefore conclude that this is acceptable.
(4) DNBR Limit In our SER on WCAP-10444, we stated that plant-specific analysis should be performedgoshowthattheDNBRlimitisnotviolatedwiththehigher value of F A employ higheY.
The licengee indicated that the VANTAGE SH fuel does not values of F A and F thus no reanalysis of DNBR transients is needed. WetNereforhconsiderthatthisconditionis satisfied for VANTAGE 5H fuel in Salem.
(5) Positive Moderator Temperature Coefficient (MTC)
In our SER on WCAP-10444, we stated +. hat if a positive moderator temperature coefficient (MTC) is intended, the same positive MTC should I
be used in the plant specific analysis. The licensee indicated that no positive MTC was considered in the submittal. We thus consider that this condition is satisfied for VANTAGE SH fuel in Salem.
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. (6) Reactor Coolant Pump Shaft Seizure In our SER on WCAP-10444, we stated that mechanistic approach (2700*F peak clad temperature) in determining the fraction of fuel failures during the reactor coolant pump seizure accident was unacceptable; the fuel failure criterion should be the 95/95 DNBR limit. The licensee reanalyzed the reactor coolant pump shaft (locked rotor) accident based on a failure criterion of peak' clad temperature of 2700*F. The licensee concluded that there was no fuel failure and the coolability was maintained since the calculated peak clad temperature (2043'F) remained much less than 2700*F and the amount of Zirconium-water reaction was small. As indicated above,
^. we disapprove the use of mechanistic approach based on 2700*F peak clad temperature in determining the fuel failure. We require the licensee to modify the fuel failure criterion based on the approved 95/95 DNBR ligit.
However, since the VANTAGE SH fuel does not employ higher values of FAu and F, we believe that there is no need to reanalyze this accident based oH the 95/95 DNBR fuel failure criterion before operation of Salem with VANTAGE SH fuel.
By letter dated May 4,1989, the licensee committed to modify the fuel failure criterion described in FSAR Section 15.4.5 so that it is based on the 95/95 DNBR limit. The next FSAR update will be mid 1990. The staff finds this acceptable.
TECHNICAL SPECIFICATION CHANGES The proposed Technical Specification changes are related to the use of VANTAGE SH fuel, a new DNBR correlation, and a new rod bow penalty r ethodology. Salem Unit 2 Technical Specifications have some variations from the Unit 1.
We discuss these changes in the following:
(1) Section 2.1.1 Basis, Pages 82-1, B2-4 and B2-6 for Units 1 and 2 The old W-3 DNBR correlation is changed to W-3 (R-Grid) correlation for Standard fuel design. A new DNBR correlation of WRB-1 is added for VANTAGE SH fuel design. All these DNBR correlations are approved for use in licensing applications. We thus consider these changes acceptable.
(2) Section 3/4.2.5 Basis, Page B3/4 2-6 for Units 1 and 2 The old phrase of minimum DNBR limit is changed to the design DNBR value because there are two different DNBR correlations intended for two different fuel designs. We consider this change acceptable.
(3) Section 3.1.3.3, Page 3/41-21 for Units 1 and Page 3/41-18 for Unit 2 The rod drop time is revised to be less than or equal to 2.7 seconds due to the use of VANTAGE SH fuel design. The licensee has taken into account the effect of the increased rod drop time in all safety analyses.
We thus consider this change acceptable.
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.. (a) Section 3.2.3, Pages 3/4 2-9, 3/4 2-10s and 3/4 2-14 for Unit 1 The rod bow penalty is revised to incorporate a new methodology which reduces the rod bow penalty. The licensee has demonstrated that the use of new DNBR correlations has enough margin to offset the rod bow penalty at burnups greater than 24,000 mwd /MTU. We thus consider that the reduced rod bow penalty is acceptable for Unit 1.
(5) Section 3.2.3 Page 3/4 2-9, Section 4.2.3.2 Pages 3/4 2-10, 3/4 2-16 and 3/4 2-17, anc Section 3/4.2.3 Basis Pages B3/4 2-4 and S3/4 2-5 for Unit 2 The revisions in these pages for Unit 2 are for the revised rod bow penalty as discussed above for Unit 1.
We thus consider these changes acceptable for Unit 2.
f THIMBLE PLUG REMOVAL In order to limit the core bypass flow, there were thimble plug devices inserted in those guide thimble tubes which were not under RCC locations or were not equipped with sources and burnable absorbers. The devices resulted in a net gain of about 2 percent in DNBR margin. The licensee intends to remove all the thiuble plug devices from the core during the transition core and all VANTAGE SH fueled core.
The licensee analyzed the inpact of thimble plug removal based on the mechanical and thermal-hydraulic design consideration. The licensee concluded that the ma,ior result of thimble plug removal is the increase of core bypass flow. The increasing bypass flow has been considered in the non-LOCA and LOCA safety analyses and no adverse impact was discovered. Based on the licensee favorable results, we conclude that the thimble plug removal is adequately addressed and the adverse impact is minimal.
We have reviewed the licensee's submittal of VANTAGE SH fuel design and Technical Specification changes for Salem Units 1 and 2 transition cores and all VANTAGE 5H cores. Based on the approved generic topical report WCAP-10444-P-A and plant-specific analyses, we approve the use of VANTAGE SH fuel design and Technical Specification changes for Salem. The commitment to modify the fuel failure criterion in FSAR Section 15.4.5, so that it is based on the 95/95 DNBR limit, in the 1990 FSAR update is acceptable.
3.0 COWENTS The State of New Jersey by letter dated March 6, 1989, commented that VANTAGE SH fuel uses grids of Zircalloy-4 instead of Inconel. The concern was that the significant hazards consideration provided by the licensee did not include an evaluation of the potential generation of an excessive
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amount of hydrogen as a result of metal-water reaction involving the grids and the reactor coolant under a postulated Loss of Coolant Accident (LOCA).- The State of New Jersey felt the potential for excessive hydrogen generation warranted an evaluation before a determination of no significant hazard consideration could be rendered.
The NRC responded to the State's concern by letter dated May 2, 1989.
That letter concluded that the use of Zircalloy in lieu of Inconel for the fuel element grid.would involve no significant hazards consideration based on:
1.
The VANTAGE SH fuel design has been reviewed and approved by the NRC on a generic basis, without' conditions pertaining to the use of Zircalloy in core structural components.
2.
The melting temperature of Zircalloy (3362*F) is much higher than-Inconel (2346'F), therefore the fuel bundles will be maintained in a coolable geenetry for a longer period of time.
3.
The weight of Zircalley in the grids is a small fraction of the total Zircalley in the core which reduces the affect of any metal-water reaction involving the grids on the overall hydrogen generation.
4 The use of Zircalloy for core structural components has been previously approved in earlier core designs.
4.0 ENVIRONMENTAL CONSIDERATION
These amendments involve a change to a requirement with respect to the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and changes to the surveillance requirements. The 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 no significant hazards consideration and the State comments on such findings have been addressed. Accordingly, the amendments meet the eligibility criteria for categorical exclusion set forth in 10 CFR51.22(c)(9). Pursuantto10CFR51.22(b),noenvironmentalimpact statement or environmental assessment need be prepared in connection with the issuance of the amendments.
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5.0 CONCLUSION
The Comission made a proposed determination that the amendments involve no significant hazards consideration which was published in the Federal Register (54 FR 6207) on February 8,1989 and consulted with the State of New Jersey. No public comments other than from the State were received.
The staff 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, and (2) such activities will be conducted in compliance with the Commission's regulations and the issuance of the amendshents will not be inimical to the common defense and security to the health and safety of the public.
Principal Contributor:
S. L. Wu Dated:
May 9, 1989 i
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