ML18096A740
| ML18096A740 | |
| Person / Time | |
|---|---|
| Site: | Salem  |
| Issue date: | 05/26/1992 |
| From: | Labruna S Public Service Enterprise Group |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML18096A741 | List: |
| References | |
| NLR-N92064, NUDOCS 9206010258 | |
| Download: ML18096A740 (16) | |
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Public Service Electric and Gas Company Stanley LaBruna Public Service Electric and Gas Company P.O. Box 236, Hancocks Bridge, NJ 08038 609-339-1200 Vice President - Nuclear Operations MAY 2 6 1992 NLR-N92064 LCR 92-04
- united states Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 Gentlemen:
REQUEST FOR AMENDMENT SALEM GENERATING STATION UNIT NOS. 1 AND 2 FACILITY OPERATING LICENSES DPR-70 AND DPR-75 DOCKET NOS. 50-272 AND 50-311 In accordance with the requirements of 10CFR50. 90., Public Service Electric and Gas Company (PSE&G) hereby transmits a request for amendment of Facility Operating Licenses DPR-70 and DPR-75 for Salem Unit Nos. 1 and 2.
Pursuant-to the requirements of 10CFR50.91(b) (1), a copy of this request for amendment has been sent to the State of New Jersey.
Specifically, PSE&G is proposing a change to the Salem Technical Specifications to reflect:
an increase to-the SHUTDOWN MARGIN requirements; a reduction in the containment pressure, high~high setpoint and allowable value; and changes to the containment spray system, containment fan cooler and service water ESF RESPONSE TIMES.
These changes are consistent with PSE&G's letter dated April 22, 1992, in which we committed to propose Technical Specification revisions consistent with the corrective actions for LER's 272/91-036 and 272/92-002. contains a qetailed description of the proposed changes and PSE&G's conclusions regarding No Significant Hazards Consideration. contains the affected Technical Specification pages with the proposed changes.
Attachments (2)
Affidavit Sincerely, flOO (
1/t
Document Control Desk NLR-N92064 Attachments (2)
Mr. J. c. Stone Licensing Project Manager Mr. T. Johnson Senior Resident Inspector Mr. T. Martin, Administrator Region I Mr. K. Tosch, Chief Bureau of Nuclear Engineering Department of Environmental Protection CN 415 Trenton, New Jersey 08625 MAY 2 6 1992
REF.:
NLR-N92064 STATE OF NEW JERSEY SS.
COUNTY OF SALEM
- s. LaBruna, being duly sworn according to law deposes and says:
I am Vice President - Nuclear Operations of Public Service Electric and Gas Company, and as such, I find the matters set forth in our letter dated MAY 2 6 1992
, concerning the Salem Generating Station, Unit No. 1, are true to the best of my knowledge, information and belief.
7 Subscribed and Sworn to before me this J__&,
day of m~ 1992 rJ;f-rn ~
fl_. ffifl My Commission expires on KIMBERLY A. HILL NOTARY PUBLIC OF NEW JERSEY My Commission Expires March 9, 1997
NLR-N92064 ATTACHMENT 1 DESCRIPTION OF PROPOSED CHANGE Revise Salem Unit 1 and 2 Technical Specifications as follows:
Specification 3/4.1.1.1:
Change the SHUTDOWN MARGIN limit from
~ 1.6% delta k/k to~ 1.85% delta k/k, effective during Unit 1, Cycle 11 and Unit 2, Cycle 7.
Table 3.3-4 (Items 2.c, 3.b.3 and 4.c):
Change the containment pressure, high-high setpoint from 5 23.5 psig to 5 15.0 psig, and the Allowable Value from 5 24.0 psig to 5 16.0 psig.
Table 3.3-5:
Change the ESF RESPONSE TIME for:
Item 2.g:
Service water system (containment pressure, high signal with loss of offsite power), from 5 48.0 seconds to 5 45.0 seconds.
Item 7.a:
The containment spray system (containment pressure, high-high signal), from 5 45.0 -seconds to 5 33.0 seconds.
Item 7.d:
Delete 7.d and replace with new item 2.h, which moves the containment fan cooler response time requirements from the
.containment pressure, high-high signal to the containment pressure, high signal.
Change the containment fan cooler response time criterion from 5 40.0 seconds to < 45.0 seconds.
REASON AND JUSTIFICATION FOR PROPOSED CHANGE These Technical Specification revisions are being proposed to reflect changes made by PSE&G under 10CFR50.59, which have resulted in administratively controlled limits more restrictive than the present Technical Specifications.
These changes were necessitated by the discovery of containment fan coil unit (CFCU) and containment spray (CS) system response times greater than originally assumed for Loss of Coolant Accident or Main Steam Line Break (LOCA/MSLB) analyses, and auxiliary feedwater (AFW) system flow greater than assumed for the MSLB analyses.
Reevaluation of the Salem licensing basis safety analyses, using assumptions consistent with these proposed Technical Specifications, are applicable to Unit 2, Cycle 7 and will be applicable to Unit 1, Cycle 11 (Unit 1 is presently in its tenth refueling outage).
The results of the reevaluation are summarized in Appendix A, and demonstrate that core response, containment temperature and pressure, and offsite radiological doses following a LOCA or MSLB would remain within acceptable limits.
L NLR-N92064 Specification 3/4.1.1.1 The proposed changes to SHUTDOWN MARGIN would make the Technical Specification limits consistent with the limits assumed in the MSLB safety analyses for Unit 1, Cycle 11 and Unit 2, Cycle 7.
The MSLB safety analyses were revised upon discovery of nonconservative auxiliary feedwater (AFW) system flows, reported in Reference 1.
PSE&G discovered the AFW flow rates following a postulated MSLB would be significantly higher than the flows assumed in the MSLB analyses.
Underestimating AFW flow for the MSLB is nonconservative because higher AFW flow to the faulted steam line increases steam generator inventory available for release out of the break, and increases primary system cooling.
Increased primary side cooling results in a greater positive reactivity insertion and also contributes to an increased mass/energy release, resulting in a more severe containment pressurization transient (for breaks inside containment).
SHUTDOWN MARGIN reduces the severity of the SLB by counteracting the return to criticality due to primary side cooling.
Therefore, 0.25% delta k/k available SHUTDOWN MARGIN, in excess of the present Technical Specification limit of 1.6% delta k/k, was credited in the SLB analyses for the Unit 2, Cycle 7 and Unit 1, Cycle 11 Reload Safety Evaluation.
PSE&G is in the process of evaluating design changes or other methods to reduce AFW flow following a postulated MSLB.
Therefore, the change to SHUTDOWN MARGIN is being requested for only one cycle of operation for each Salem unit.
Table 3.3-4 The containment pressure at which the cs system is assumed to actuate in the LOCA/MSLB analyses has been reduced from 25.4 psig to 17.0 psig.
PSE&G's setpoint calculations indicate that a maximum trip setpoint of 15.85 psig and maximum allowable value of 16.58 psig are needed to support an analytical limit of 17.0 psig.
During the Unit 2 sixth refueling outage, the setpoint was lowered from 23.5 psig to 15.0 psig, and the allowable value was lowered from 24.0 psig to 16.0 psig.
These changes support an analytical limit of 17.0 psig, with positive margin relative to the setpoint calculations.
Lowering the containment pressure setpoint for CS system actuation following a LOCA or MSLB, reduces the post accident containment pressure and temperature.
Therefore, this change was credited in the Unit 2, Cycle 7 Reload Safety Evaluation to help offset the effects of the AFW flow condition reported in Reference 1, and the containment spray fluid travel time increase reported in Reference 2 (described below).
A similar change will be implemented during the Unit 1 tenth refueling outage, to support the Reload Safety Evaluation for Unit 1, cycle 11.
Table 3.3-5 During _a review of the Salem UFSAR, PSE&G identified a discrepancy in the response times for CFCU's and the cs system.
NLR-N92064 With regard to the containment analyses for LOCA and MSLB, Salem UFSAR Section 15.4.8.2.3 states:
"In all analyses, the times assumed for the initiation of containment sprays and fan coolers are 59 and 35 seconds, respectively, following the appropriate initiating trip signal.
These times are based on the assumption of loss of offsite power, and the delays are consistent with Technical Specification limits.
The delay time for spray delivery includes the time required for the spray pumps to reach full speed and the time required to fill the spray headers and piping."
Technical Specification Table 3.3-5 (Unit 1 and 2) defines ESF RESPONSE TIME test criteria for the CFCU's and the CS system.
Containment Pressure Containment Spray Containment Fan Coolers High-High
~ 45 seconds
~ 40 seconds It was also discovered that response time testing for the CFCU's and the CS system did not include delays associated with Loss of Offsite Power (LOOP).
The service water Technical Specification response time from the containment pressure, high signal is 48 seconds.
Because the CFCU's rely on increased service water flow, service water response must be consistent with CFCU response time requirements.
This discrepancy was identified during Unit 1 Cycle 10 and Unit 2 Cycle 6.
The 18 month ESF response time test data from Unit 1 ninth refueling and Unit 2 fifth refueling were reviewed against the safety analysis assumptions to determine operability of the CFCU and CS systems.
Test.data from 1R6 through 1R8 and 2R2 through 2R4 were also reviewed to help determine safety significance and reportability of the discrepancies.
These test data are summarized in Table 1, and demonstrated the Technical Specification limits were not exceeded.
The eight sets of test data reviewed, combined with system performance characteristics (e.g., CS pump typically starts in approximately 2 seconds) and separate acceptance criteria for diesel start times and load sequencing delays, were deemed sufficient to conclude the discrepancies did not result in a violation of Technical Specifications, nor would they have prevented fulfillment of a safety function.
CFCU's and Service Water System Based on test data CFCU response time exceeded the 35 seconds assumed in the safety analyses, but a reevaluation using 45 seconds showed the containment pressure and temperature, following a LOCA or MSLB, would remain within acceptable limits.
Therefore, the CFCU response time in Table 3.3-5 is being changed from 40 to 45 seconds.
Because CFCU emergency heat removal rate is based on increased service water flow, service water response time in Table 3.3-5 is being changed from 48 to 45 seconds.
NLR-N92064 The Technical Specifications incorrectly list the CFCU's under the containment pressure, high-high signal.
CFCU's are actuated from the containment pressure, high signal.
The Technical Specifications are being revised to reflect this by moving the CFCU's from Item 7.d to Item 2.h on Table 3.3-5.
Containment Spray System The CS system ESF response time test ends when the spray pump has reached a point on its pump curve in recirculation flow (pump discharge valve opening time is considered, but is typically not limiting).
The licensing basis safety analyses assumed that it takes an additional 28 seconds for flow to travel through the header and exit the spray nozzles.
This assumption was based on input provided to Westinghouse by a PSE&G memo (6/29/78).
Because the memo does not meet PSE&G's present standards for engineering calculations, a Discrepancy Evaluation Form (DEF) was written in accordance with our Engineering Discrepancy Control process.
Recalculation of the spray fluid travel time resulted in an increase from 28 seconds to 47 seconds.
This increased time was reported in Reference 2.
In order to account for the 47 second travel time, the LOCA/MSLB analyses were reevaluated, increasing the assumed total response for the CS system from 59 to 80 seconds.
An 80 second total response time, with 47 seconds allocated to fluid travel time, requires a 33 second ESF response time test criterion.
Therefore, the CS response time of Table 3.3-5 is being revised to 33 seconds.
DETERMINATION OF NO SIGNIFICANT HAZARDS CONSIDE~TION The proposed changes to the Salem Generating Station Technical Specifications would increase the minimum SHUTDOWN MARGIN required during MODES 1 through 4 from 1.6% delta k/k to 1.85% delta k/k; reduce the containment pressure, high-high setpoint from 23.5 psig to 15.0 psig, and the allowable value from 24.0 psig to 16.0 psig; decrease the ESF RESPONSE TIME for service water system (from containment pressure, high signal with loss of offsite power), from 5 48.0 seconds to 5 45.0 seconds; decrease the ESF RESPONSE TIME for containment spray system, from 5 45.0 seconds to 5 33.0 seconds; increase the containment fan cooler ESF RESPONSE TIME from 5 40.0 seconds to 5 45.0 seconds; and relocate the containment fan cooler time criterion from the containment pressure, high-high signal to the containment pressure, high signal.
NLR-N92064 These proposed changes: 1)
Do not involve a significant increase in the probability or consequences of an accident previously evaluated.
The proposed changes affect Salem Generating station (SGS) Loss of Coolant Accident (LOCA) and Main Steam Line Break (MSLB) safety analyses assumptions.
These changes have been evaluated to demonstrate that the analysis results remain within acceptable limits as defined by the SGS licensing basis.
In particular:
o The calculated peak containment pressure would remain below the SGS design limit of 47 psig.
o The calculated containment temperature response would not adversely impact the qualification of equipment subject to the SGS Environmental Qualification program.
o Core response to a postulated MSLB, assessed in terms of Departure From Nucleate Boiling Ratio, would remain within acceptable limits.
o Calculated offsite radiological doses would remain well within the limits of 10CFRlOO.
- 2)
Do not create the possibility of a new or different kind of accident from any accident previously evaluated.
The proposed changes involve a setpoint change, response time changes and more restrictive SHUTDOWN MARGIN limits.
They do not involve any new system configurations with the potential for changing the initiation of an accident, nor do they introduce any previously,unconsidered equipment failure modes.
- 3)
Do not involve a significant reduction in a margin of safety.
The SGS licensing basis safety analysis limits define an acceptable margin of safety for plant operation.
The analyses affected by the proposed changes (LOCA and MSLB) have been reevaluated to demonstrate the safety analysis limits are not exceeded.
As discussed above, PSE&G has concluded that the proposed changes to the Technical Specifications do not involve a significant hazards consideration because the changes:
(i) do not involve a significant increase in the probability or consequences of an accident previously evaluated, (ii) do not create the possibility of a new or different kind of accident from any accident previously evaluated, and (iii) do not involve a significant reduction in a margin of safety.
NLR-N92064 REFERENCES 1)
Licensee Event Report 272/91-036, January 9, 1992, "Discovery of Nonconservative Auxiliary Feedwater Flow Rates For Steam Line Break Analyses."
- 2)
LER 272/92-002-00, February 18, 1992, "Containment Spray Fluid Travel Time Greater Than Originally Assumed."
NLR-N92064 Table 1 ESF RESPONSE TIME Test Data Summary 1R6 through 1R9 and 2R2 through 2R5 Loss of Offsite Power Assumed CFCU Service Water 1R9 35.8 sec.
29.2 sec.
1R8 37.0 28.9 1R7 36.4 29.7 1R6 37.8 29.1 2R5 39.5 29.6 2R4 37.4 32.7 2R3 37.8 29.5 2R2 38.5 28.6 Cont. Spray 23.4 sec.
24.2 23.3 24.0 24.0 22.8 22.7 27.6 In all cases, the values are less than the present and proposed Technical Specification requirements.
Unit 1, refueling outages 6 through 9; Unit 2, refueling outages 2 through 5.
Appendix A Results of Safety Analysis Reevaluation Increased auxiliary feedwater (AFW) flows, increased containment fan coil unit (CFCU) response time and increased containment spray (CS) delay time were evaluated for Salem Generating Station (SGS), in accordance with the criteria of 10CFR50.59.
The evaluations concluded that no unreviewed safety question exists, by demonstrating that the conclusions for the UFSAR safety analyses remain valid.
The following are the principal changes to the safety analyses assumptions considered in the evaluation:
- 1)
CFCU's are operating 45 seconds after the containment pressure, high signal is reached (changed from 35 seconds).
This change results in a penalty to the calculated containment pressure and temperature response, by delaying the initiation of heat removal.
- 2)
The CS system is delivering flow into the containment atmosphere 80 seconds after the containment pressure, high-high signal is reached (changed from 59 seconds).
This change also results in a penalty to the calculated containment temperature and pressure response.
Because the radiological dose analyses take credit for iodine removal by the CS system, the increased delay time was also reviewed for impact on offsite dose releases.
- 3)
As reported in LER 272/91-036, newly calculated flows identified an increase to the total integrated AFW delivered to the faulted loop following a Main Steam Line Break (MSLB).
This results in a penalty to the calculated MSLB core response and containment response, because greater AFW flows result in greater primary system cooling and mass/energy release to containment.
Increased primary system cooling results in a higher positive reactivity insertion, contributing to the return to criticality and the mass and energy released inside containment.
- 4)
Available SHUTDOWN MARGIN is assumed to be 1.85 % delta k/k (changed from 1.6 %).
This change results in a net benefit for the core response to a MSLB, by limiting the return to criticality transient resulting from excessive primary system cooling.
This consequently reduces the calculated mass and energy released inside containment, thereby benefitting containment temperature and pressure response.
NLR-N92064 Appendix A 5)
The containment pressure, high-high signal occurs at 17.0 psig (changed from 25.4 psig).
This change results in a benefit to containment temperature and pressure response, by initiating containment spray at a lower containment pressure.
Containment Integrity Analysis for MSLB Analyses for MSLB mass and energy releases inside containment are performed to ensure that the containment pressure and temperatures do not exceed design limits.
The peak containment pressure calculated for each case must be below the Salem Unit 2 containment design pressure of 47 psig.
The containment temperature response is evaluated to demonstrate that the safety-related instrumentation is environmentally qualified.
Cases Analyzed The following MSLB mass and energy cases were reanalyzed using input assumptions consistent with the current plant operating conditions:
o 70% Power, Split Break, Diesel Failure.
o 30% Power, Split Break, Diesel Failure.
o 30% Power, Split Break, Auxiliary Feedwater Runout Protection Failure.
o 102% Power, large Double Ended Rupture, Failure of the Feedwater Control Valve to Close.
o 102% Power, Large Double Ended Rupture, Failure of the Auxiliary Feedwater Runout Protection.
The partial power cases were reanalyzed for containment pressure concerns since they exhibited the highest peak pressures of the cases previously analyzed in the Salem licensing basis.
Other less "limiting cases were not reanalyzed because either the predicted peak pressure is significantly lower than the design limit, or similar sensitivities to the containment pressure are expected.
In addition, two full power cases were reanalyzed to assess the potential impact of containment temperature on Environmental Qualification of equipment.
Results of MSLB Containment Integrity Analysis - Pressure and Temperature Response For all cases analyzed the resultant calculated peak containment pressures are less than the previous licensing basis calculated pressure due to the SHUTDOWN MARGIN and containment pressure, high-high setpoint assumptions made in the analysis.
The 70%
NLR-N92064 Appendix A '
power split break with a diesel failure, results in the highest peak containment pressure (45.5 psig).
All other MSLB cases are less limiting for peak containment pressure and are expected to exhibit approximately the same net benefit as the cases analyzed above.
Therefore, the calculated peak containment pressure remains below the containment design pressure of 47.0 psig.
Similarly, the containment temperature response for all the cases reanalyzed are bounded by previously calculated temperatures.
There is therefore no impact on the environmental qualification of equipment inside containment.
Containment Integrity Analysis -
Loss of Coolant Accident The Loss of Coolant Accident (LOCA) has been reevaluated to ensure that the containment pressure and temperatures do not exceed acceptable limits.
The containment mass and energy analyses for short and long term consequences of a LOCA are described in the UFSAR Section 15.4.
For the Short Term Mass and Energy Release analysis the effect of an increase in AFW flow has no adverse impact on the current licensing analysis.
AFW is not modeled in this analysis because of the short duration of the transient (~ 3 seconds)
- Consequently, a change in the flowrate does not impact this analysis.
For the Long Term LOCA Mass and Energy Release Analysis, sensitivity analyses reveal that the AFW model has conservatively small impact on the results in this analysis (increased flow would be a slight benefit for long term depressurization).
AFW flow is modeled during the period following peak containment pressure.
Therefore, an increase in AFW flow rate will not affect the results of the licensing basis analysis.
For the Long Term LOCA Mass and Energy Release Analysis, the peak calculated containment pressure is 45.73 psig for the double-ended pump suction break, with minimum safety injection flow and a diesel failure.
This is less than the maximum containment pressure design value of 47 psig.
Main Steam Line Break Core Response An evaluation of the limiting case of the MSLB core response event was performed for the increased AFW flowrates (core response to a MSLB is not affected by the increase in CFCU or CS delay time).
The evaluation shows a slight increase in the peak heat flux and small changes in pressurizer pressure and cold leg inlet temperature.
There is ample margin to departure from nucleate boiling in the MSLB analysis to cover these small changes.
Therefore, the core response to a MSLB would remain within acceptable limits (i.e, DNBR remains greater than the limits of UFSAR Section 4.4).
NLR-N92064 Appendix A Radiological Dose Evaluation Containment sprays are utilized in the large-break LOCA offsite dose analysis to remove elemental and particulate iodine from the containment atmosphere, to help ensure the offsite radiological doses from a postulated accident would meet the requirements of 10CFR100.
The LOCA dose analysis of record is presented in Section 15.4 of the Salem UFSAR.
Limiting the release of radioactive iodine is necessary to minimize the thyroid doses resulting from an accident.
Based on 10CFRl00.11, the plant design, in combination with the selected plant site, must have calculated accident doses that are less than 300 rem to the thyroid.
Iodine Removal Evaluation The assumptions of the NRC Safety Guide 4 based dose analysis presented in the UFSAR do not include a delay in the initiation of iodine removal by spray.
A total CS delay of 80 seconds is reviewed relative to the impact of off si.te thyroid doses.
The estimated iodine release to the environment during the initial 80 second period following the initiation of the LOCA is 38 curies of Dose Equivalent I-131 without spray operation and 35 curies with spray operation.
Thus, the 80 second delay in spray operation results in an additional 3 curies of iodine released to the environment.
This equates to an increase in the zero to 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> site boundary thyroid dose of approximately 1 rem.
This would result in a 97 rem thyroid dose, which remains well below the 10CFRlOO limit of 300 rem.
The UFSAR dose analysis is conservative in that it uses the Safety Guide 1.4 assumption that 10% of total radioiodine inventory is organic, and therefore not available for removal by the cs system.
The more current guidance of Regulatory Guide 1.4 assumes that 4% of radioiodine is organic, which would increase the amount available for spray removal by 6%.
Other Safety Analyses No other safety analyses are adversely impacted by increasing CFCU and cs delays, or by increasing AFW flows.
Large break LOCA analyses for ECCS performance conservatively minimize containment spray and fan cooler response time, in order to minimize ECCS backpressure.
The containment external pressure analysis (UFSAR section 6.2) assumes actuation of the cs system at zero psig, and is therefore not affected by the containment pressure, high-high setpoint reduction.
Small break LOCA is the only LOCA analysis which models AFW flow.
Because the analysis uses the minimum flow (i.e., more flow is a benefit), the increased AFW flow has no adverse effect on the analysis.
NLR-N92064 Appendix A Non-LOCA events (except MSLB inside containment) which use AFW, use minimum AFW flows in their analyses.
They are therefore not adversely affected by the increased AFW flow.
Conclusions The Salem Generating Station (SGS) safety analyses impacted by increased AFW flow, increased CFCU and CS delay times, have been reevaluated to demonstrate they remain within the limits of the SGS licensing basis.
- NLR-N92064 ATTACHMENT 2