ML20195D107
| ML20195D107 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 10/28/1988 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20195D105 | List: |
| References | |
| NUDOCS 8811040193 | |
| Download: ML20195D107 (8) | |
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO. 75 TO FACILITY OPERATING LICENSE NO. NPF-12 SOUTH CAROLINA ELECTR.iC & GAS COMPANY SOUTH CAROLINA PUBLIC SERVICE AUTHORITY VIRGIL C. SUMMER NUCLEAR STATION, UNIT NO. 1 DOCKET NO. 50-395
- 1. 0 INTRODUCTION By letter dated May 20, 1988, as supplemented June 20, 1988, July 8, 1988, South Carolina Electric & Gas Company (the licensee) submitted a request for changes to the Virgil C. Summer Nuclear Station, Unit No.1 (Summer Station), Technical Specifications (TS).
The Summer Station TS would be amended to insurporate changes necessary as a result of the utilization of the Vantage 5 fuel.
The proposed changes are discussed in Section 2.2.
In the August 10, 1988 Federal Register (53 FR 30144), the Commission published a "Notice of Consideratio1 of Issuance of Am o dment to Facility Operating License and Proposed No Significant Hazards Cons 41eratio,1 Determination and Opportunity for Hearing." The submittals dated August 5, 1988, August 31, 1988, September 16, 1988, September 30, 1988, October 11, 1988, October 13, 1988, and Octooer 24, 1988, provided additional clarifying information to support the licensee's proposad amendment.
It did not change the (mendment request, nor the initial proposed determina-tion of no significant hazards consideration.
Therefore, this information was not the subject of another notice.
Currentiy, the Summer Station is operating in Cycle 4 with a Westinghouse Il x 17 low parasitic (LOPAR) fueled core.
Future core loaa1ngs are planned to consist of a mixed core of LOPAR ard VANTAGE 5 fuel in Cycle 5 with all VANTAGE 5 cores to be used after Cycle 5.
The major mechanical design featefes of the VANTAGE 5 fuel, relative to the current LOPAR fuel, include the following:
(s) Integral fuel Burnable Absorber (IFBA),
(b) Intermefate Flow Mixer (IFM) Grids, (c) Reconstitutable Top Nozzle, (d) Extended Burnup Capability, (e) Axial Blankets, (f) Six Intermediate Zircaloy Grids, and (g) Smaller Diameter in each Fuel Rod, Guide Thimble, and Instrumentation Tube.
Tha safety analyses for the transition core and full VANTAGE 5 core were performed by the licensee at a thermal power level of 2775 MWt, Conser-vative assumptions include a full power F of 1.62 for a tra W tion core and1.68forthefullVANTAGE5 core;amNimumF of 2.45; 15% steam 0
generator tube plugging; and a positive moderator temperature coefficient GS11040193 GG1028 PDR ADOCK 05000395 PDC P
. (MTC) from 0 to 70% power and then decreasing ?inearly to a zero MTC from 70 to 100% power.
However, the Large Break Loss-of-Coolant-Accident (LOCA) analysis was performed witt. a F of 1.62 for both transition and AH full VANTAGE 5 cores The VANTAGE 5 fuel design has been approved, with conditions, in the Westinghouse topical report WCAP-10444-P-A, "Reference Core Report VANTAGE 5 Fuel Assembly." During the review of VANTAGE 5 fuel design in WCAP-10444-P-A, the NRC staff identified a few conditions to be resolved for those licensees using VANTAGE 5 fuel design.
These conditions were addressed in the licensee's submittal of August 5,1988.
The staff's Safety Evaluation (SE) of the licensee's response to these conditions and the adequacy and the appropriateness of the proposed TS changes follows.
2.0 EVALUATION 2.1 Conditions of WCAP-10444-p-A (1) Statistical Convolution Method In the staff's SE on WCAP-10444-P-A, it was stated that the statis-tical method should not be used for VANTAGE 5 fuel for evaluating the fuel rod shoulder gap.
The licensee indicated that the statistical convolution method was not used for the application of the VANTAGE 5 fuel design at Summer Station.
Also, the currently approved NRC method was used for evaluating fuel rod shoulder gap.
Therefore, the staff considers the licensee's addressing of this condition accept-able.
(2) Seismic and LOCA loads In the staff's SE on WCAP-10444-P-A, it was stated that for each plant specific application, it must be demonstrated that the VANTAGE 5 fuel assembly will maintain a coolable geometry under combined seismic and LOCA loads.
The licensee performed LOCA and seismic loading analyses for the transition core and the all VANTAGE 5 core using an approved method.
The results showed that the fuel assembly l
in eitSer casa has enough margin to sustain the combined seismic and LOCA loads such that the structural integrity and coolible geometry are mafMtained.
Based on the licensee's acceptable results, the staff has concluded that the licensee has adequately addressed the conditt6n of s'eismic and LOCA loads.
(3)
Irradiation Demonstration Program l
In the staff's SE on WCAP-10444-P-A, the staff stated that they would require that an irradia* ion program bo performed to confirm the VANTAGE 5 fuel performante.
The licensee stated that Summer Station has four VANTAGE 5 demonsteation assemblies irradiated up to an I
assembly average of 30,000 MWD /MTU.
Post-irradiation examinations l
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. showed all four assemblies were of good mechanical integrity.
These four assemblies have been reinserted for continuing irradiation.
The staff, thus, concludes that the VANTAGE 5 fuel will perform satis-factorily in the Summer Station core.
(4) Improved Thermal Design Procedure (ITOP)
In the SE on WCAP-10444-P-A, the staff stated that those thernal hydraulic restrictions, which were applied in approving the use of Westinghouse improved thermal design procedure (ITOP), should also be applied to the VANTAGE 5 fuel design.
The licensee indicated that they conformed to these restrictions of ITOP for Summer Station.
The staff, therefore, concludes that this is acceptable.
(5) Departure from Nucleate Boiling (ON8R) Limit In the SE in WCAP-10444-P-A, it was stated that a plant-specific analysis shou'ad be performed to show that the ONBR limit is not violated with the higher value of F
, The licensee examined all the transientanalysesrelatedtoDNBReWicuiations(1.s2forthetran-sition core and 1.68 for the all VANTAGE 5 core excluding the large break LOCA analysis), and concluded that there were no DNBR limit violations.
The staff has reviewed the licensee's analysis and has concluded that it is acceptable.
(6) Reactor Coolant Pump Shaft Seizure In the staff's SE on WCAP-10444 P-A, it was stated that the mechanistic approach in determining the fraction of fuel failures during the reactor coolant pump shaft seizure accident was unacceptable, and that the fuel failure criterion should be the 95/95 DNBR limit.
The licensee reanalyzed this accident using approved computer codes.
The results showed that the number of fuel failures was less than 15%
of the total fuel rods in the core based on the 95/95 DNBR limit.
J Based on the acceptable fuel failure criterion of the 95/95 ONBR If91t, the staff concludes that the reactor coolant pump shaf t seizure accident is satisfacterily addressed for VANTAGE 5 fuel.
(7) Positive Moderator Temperature Coefficient In the staff's SE on WCAP-10444-P-A, it was stated that if a positive MTC ir-Intended, the same positive MTC should be used in the plant-specific analysis.
The licensee indicated that a positive MTC was l
considered in the analyses, and all appropriate safety criteria for non-LOCA accidents were not changed from previous FSAR results.
Consequently, the staff considers this acceptable, i
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(8) LOCA Analysis In the staff's SE t,n WCAP-10444-P-A, it was stated that the plant-specific LOCA analysis should be performed to show that the require-ments of 10 CFR Part 50 are met.
The licensee analyzed large break LOCA and small break LOCA using the approved Westinghouse LOCA r
Evaluation Model with a F of 2.45.
The results show that all the 9
requirements in 10 CFR 50.46 and Appendix K to 10 CFR 50 were met.
The staff, therefore, concludes that the requirements of 10 CFR Part l
50 and Appendix K to 10 CFR Part 50 are satisfied for the utilization of the VANTAGE 5 fuel in Summer Station cores.
l However, because the large break LCCA analysis was performed with an
[
F,Uensee.62forthefullVANTAGE5 cores,ratherthan1.68,the of 1 i
IT will be required to subait a new large break LOCA analysis f
if an F higher than 1.62 is to be used for the full VANTAGE 5 core.
3g 2.2 Technical Specification Changes The proposed Technict) Specification changes, as discussed below, include:
i (1) Core Safety Limits (Figure 2.1-1), (2) Thermal Design Flow (Table 2.2-1), (3) Overpower /0vertemperature Setpoints (Table 2.2-1), (4) Shut-i down Margin for Modes 3, 4, and 5 (Figure 3.1-3), (5) Moderator Tempera-l ture Coefficient Limits (Sections 3/4.1.1.3 and the addition of Figure t
3.1.0), (6) Borated Water Sources (Sections 3.1.2.5 and 3.1.2.6), (7)
Axial Flux Difference (Sections 3.1.3.4 and 3/4.2.1), (8) Heat Flux Hot Channel Factor F (Section 3.2.2 and Figures 3.2-1 and 3.P.-2), (9) F Surveillance (Se9 tion 4.2.2.1),(10) NuclearEnthalpyRiseHotChannkl Factor (Section 3/4.2.3 and Figure 3.2-2), (11) DNB Parameters (Table 3.2-1), (12) Overtemperature/0verpower Trip Response Times (Table 3.3-2),
(13) Reactor Coolant Pump Underfrequency Trip Response Time (Table 3.3-2),
(14) ECCS Accumulators (Section 3.5.1), (15) Charging Pump Surveillance l
(Section 4.5.2), (16) Surveillance during Physics Tests (4.10.2), and (17)
Radial Peaking Factor Limit Report (6.9.1.11).
t Assorted Bases sections were proposed to be revised to reflect the changes
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associated with the safety limits and limiting safety system settings, limiting conditions for operation, and surveillance requirements.
These changes have_been reviewed by the staff and have been judged ecceptable, i
althcogh they are not addressed forther in this SE.
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(1) Core Safety Limits The core safety limits are revised to reflect the use of VANTAGE 5, ITOP, WRB-1 (LOPAR fuel) and WRB-2 (VANTAGE 5 fuel) ONS correlation, i
and F of 1.62.
Based on the approved WCAP-10444-P-A, ITOP method, andDNRcorrelations,thestaffconcludesthattherevisedcore f
safety limits are acceptable.
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. (2) Thermal Desian Flow The thermal design flow is reduced to accommodate the increased resistance of VANTAGE 5 fuel assembly with 15% steam generator tube plugging in all three steam generators.
Based on the approved method in analyzing the reduced flow, the staff considers that the reduced thermal design flow is acceptable.
(3) Overpower /0vertemperature Setpoints Overpower and overtemperature setpoints are revised to maintain consistency with the non-LOCA accident analyses.
Since the revised setpoints are based on the approved method in WCAP-8745, the staff approves the revised overpower and overtemperature setpoints.
(4) Shutdown Marain for Modes 3, 4 and 5 The requirements of shutdown margins for Modes 3, 4, and 5 ar1 revised to reflect the use of VANTAGE 5 fuel during boron dilution event.
Since the analysis is based on the approved method, the staff considers the revised requirements of shutdown margin for Modes 3, 4 and 5 are acceptable.
(5) Moderator Temperature Coefficient (MTC) Limits The MTC limit is revised to reflect a positive MTC from 0 to 70%
power and then decreasing linearly to a zero MTC from 70 to 100%
power.
This revision is required due to the increased RCS boron concentrations for VANTAGE 5 fuel.
The licensee proposed the addition of a new Figure 3.1.0 which presents the acceptable and unacceptable regions for operation with the MTC on the Figure, as a function of percent of thermal power level.
The staff considers the proposed revision acceptable.
(6) Bora_ted Water Sources An increase in the minimum borated water volume for refueling water storage tank (RWST) and the basic acid storage system are proposed to ref1ect_the use of VANTAGE 5 fuel and extended fuel cycles.
The stat f considers these increases acceptable.
(7) Axial PIux Dif'ference The axial power distribution control is revised to follow the recommendation of the Relaxed Axial Offset Control (RAOC) procedure.
Since the RAOC procedure is described in the approved report WCAP-10216-P-A, the staff considers this revision acceptable.
9 (8) Heat Flux Hot Channel Factor (F )
The peaking factor Fn is increased to 2.45 to allow for greater operational flexibi1Yty due to the use of VANTAGE 5 fuel.
The existing Figure 3.2-1 was proposed to be deleted and the axisting Figure 3.2-2 was proposed to be revised and renumbered u Figure 3.2-1.
The new figure 3.2-1 provided K(z)-Normalized F (z) as a function of core height.
Thischangewasmadetorefle9tthenew limits as a result of the new LOCA analysis.
The existing Figure 3.2-3 was renumbered as Figure 3.2-2, and the Figure was revised.
This revision to the Figure was proposed to reflect an F Since the licensee has performed all the analyses based $ of 1.62.
the F of 2.45, the staff considers this revision acceptable.
q (9) F Surveillance q
The licensee proposes to use F surveillance to replace the current F
surveillance.
Since the F surveillance is described in the a$rovedreportWCAP-10216-P-A the staff considers this change acceptable.
(10) Nuclear Enthalpy Rise Hot Channel Factor (F3g)
TheF[useofVANTAGE5 fuel.is increased to allow for greater operational flexibilit to th This reason for the change is similar to the reason for the change in F.
acceptable.
q The staff considers this change (11) DNB Parameters The limits of the DNB parameters, T and pressurizer pressure, are revisedtobeconsistentwiththenN9 analyses due to the use of VANTAGE 5 fuel.
The staff considers these changes acceptable.
(12) Overtemperature/ Overpower Trip Response Times The evertemperature and overpower trip response times are revised to become 8.5 seconds.
Since the slightly increased response times are consist,ent with the analyses, the staff considers there changes acceptarble.
(13)Reacto[CoolaNtPump(RCP)UnderfrequencyTripResponseTime A decrease in the RCP underfrequency trip response time is proposed.
Since this change is consistent with the new analysis, the staff considers this change acceptable.
(14) ECCS Accumulators A change to the contained borated 'ater volume of the ECCS accumu-lators is proposed.
The proposed change is consistent with the LOCA and non-LOCA analyses.
Thus, the staff considers the change accept-able.
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, (15) Changing Pump Surveillance Test Limits A change to the charging pump flow balance test limits is proposed.
The proposed change is based on the revised safety analyses.
- Thus, the staff considers the change acceptable.
(16) Physics Tests Surveillance Requirements The licensee proposed changes to the surveillance requirement i
specification numbers for physics tests to reflect the correct i
surveillance section numbers, as a result of the switching from the use of F to use of F.
The staff considers these changes to the I
surveillEcerequiremektsacceptable.
(17) Radial Peaking Factor Limit Report Administrative Control Section 6.9.1.11, Radial Peaking Factor Limit Report, was proposed to be revised to reflect operation utili'ing VANTAGE 5 fuel, RAOC, and baseload operation.
The staff consio c s this proposed change acceptable.
2.3 Thimble Plug Removal In order to limit the core bypass flow, thimble plug devices were inserted in those guide thimble tubes which were not under Rod Cluster Control (RCC) locations or were not equipped with sources and burnable absorbers.
The devices resulted in a net gain of about 2% in DNBR margin.
The licensee intends to remove the thimble plug devices from the core prinr to operation with the transition core and the all VANTAGE 5 fueled c.oro, as appropriate.
The licensee analyzed the impact of thimble plug removal based on the mechanical and thermal-hydraulic design consideration.
The licensee l
concluded that the major result of thimble plug removal was the increase l
in core bypass flow; and, therefore, it is acceptable to remove all or any combination of the thimble plug devices.
Since the increasing bypass flow was considereo in the non-LOCA and LOCA safety analyses, and no adverse impact was discovered, the staff concludes that the thimble plug removal isadequate{y, addressed.
- 2. 4 Desian_ Basis _ Accident Analyses Relative to the Use of VANTAGE 5 Fuel Amendment 74 to the Summer Station license approved the storage of VANTAGE 5 fuel, both new and irradiated, in the sent fuel pool and the fresh fuel pool.
In the SE which approved that amendment, a radiological dose evaluation was included.
This evaluation stated that the utilization of the VANTAGE 5 fuel, when compared to the operation with the LOPAR fuel, would result in the radiological doses associated with postulated accidents remaining virtually unchanged with the exceptinn of the fuel handling accident.
This same conclusion is also applicable for incor-poration into this SE and is, therefore, referenced.
The results of the fuel handling accident based upon the use of the VANTAGE 5 fuel would remain unchanged from that presented in the SE for Amendment 74.
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3.0 ENVIRONMENTAL CONSIDERATION
This amendment involves a ch=aca in 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 staf f has 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 off site, and that there is no significant increase in individual or cumula-tive occupational radiation exposure.
The Commission has previously issued a proposed finding that this amendment involves no significant hazards consideration, and there has been no public comment on such finding.
Accordingly, this amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR Section 51.22(c)(9).
Pursuant to 10 CFR 51.22(b), no environmental impact statement or environ-mental assessment need be prepared in connection with the issuance of this amendment.
4.0 CONCLUSION
The Commission has issued a "Notice of Consideration of Issuance of Amendment to Facility Operating License and Proposed No Significant Hazards Consideration Determination and Opportunity for Hearing" which has published in the FEDERAL REGISTER on August 10, 1988 (53 FR 30143) and consulted with the State of South Carolina.
No public comments or requests for hearing were received, and the State of South Carolina did not have comments.
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 Conmission's regulations and the issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributors:
S. Wu J. Hayes Dated: October 28, 1988 J'
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