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| | number = ML20212N840 | | | number = ML20212N840 |
| | issue date = 08/22/1986 | | | issue date = 08/22/1986 |
| | title = SER Supporting Util Response to Item 1.C of NRC 840411 Ltr Re No Specific Time Limit Necessary on Containment Purging & Venting During Reactor Operation | | | title = SER Supporting Util Response to Item 1.C of NRC Re No Specific Time Limit Necessary on Containment Purging & Venting During Reactor Operation |
| | author name = | | | author name = |
| | author affiliation = NRC OFFICE OF NUCLEAR REACTOR REGULATION (NRR) | | | author affiliation = NRC OFFICE OF NUCLEAR REACTOR REGULATION (NRR) |
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| | contact person = | | | contact person = |
| | document report number = NUDOCS 8608290202 | | | document report number = NUDOCS 8608290202 |
| | | title reference date = 04-11-1984 |
| | package number = ML20212N829 | | | package number = ML20212N829 |
| | document type = SAFETY EVALUATION REPORT--LICENSING & RELATED ISSUES, TEXT-SAFETY REPORT | | | document type = SAFETY EVALUATION REPORT--LICENSING & RELATED ISSUES, TEXT-SAFETY REPORT |
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| In a letter to the licensee dated November 29, 1978, the staff identified two areas of concern associated with operation of the containment vent and purge valves while the plant is at power. The concerns relate to the following possible events: 1) a LOCA occurring while the isolation signals for opening the purge / vent valves are overridden, and 2) a LOCA occurrina durina purge / vent valve operations. Both of these events could produce unacceptable radioactive releases. The letter requested the licensee to propose a technical specifica-tion either to prohibit venting and purging during onwer operation or to limit the venting and purging operations to 90 hours per year with adequate justifi-cation. As an alternative, the licensee could provide justification for unlimited usage of the vent and purge lines. In response to the letter, the licensee provided information concerninc the operation of their vent and purge valves. On the basis of that informaticn, the staff issued safety evaluations (SE) on April 11 and September 24, 198/. These SEs indicated that the licensee's approach was acceptable, pending receipt of adequate justification for not requiring a vent and purge time limitation. | | In a letter to the licensee dated November 29, 1978, the staff identified two areas of concern associated with operation of the containment vent and purge valves while the plant is at power. The concerns relate to the following possible events: 1) a LOCA occurring while the isolation signals for opening the purge / vent valves are overridden, and 2) a LOCA occurrina durina purge / vent valve operations. Both of these events could produce unacceptable radioactive releases. The letter requested the licensee to propose a technical specifica-tion either to prohibit venting and purging during onwer operation or to limit the venting and purging operations to 90 hours per year with adequate justifi-cation. As an alternative, the licensee could provide justification for unlimited usage of the vent and purge lines. In response to the letter, the licensee provided information concerninc the operation of their vent and purge valves. On the basis of that informaticn, the staff issued safety evaluations (SE) on April 11 and September 24, 198/. These SEs indicated that the licensee's approach was acceptable, pending receipt of adequate justification for not requiring a vent and purge time limitation. |
| By letters dated April 1, 1985 and October 23, 1985, the licensee submitted additional information supporting its proposal not to have any operational limitation on use of the vent and porce valves during power operation. This evaluation deals with the acceptability of that proposal. , | | By letters dated April 1, 1985 and October 23, 1985, the licensee submitted additional information supporting its proposal not to have any operational limitation on use of the vent and porce valves during power operation. This evaluation deals with the acceptability of that proposal. , |
| 2.0 EVAltlATION The April 1,1985 letter provided the results of a licensee LOCA dose analysis for the 20-inch vent and purge valves. The analysis assumed the following l | | 2.0 EVAltlATION The {{letter dated|date=April 1, 1985|text=April 1,1985 letter}} provided the results of a licensee LOCA dose analysis for the 20-inch vent and purge valves. The analysis assumed the following l |
| ( conditions: | | ( conditions: |
| * A large pipe break inside the containment instantaneously releases the entire primary coolant mass to the drywell. | | * A large pipe break inside the containment instantaneously releases the entire primary coolant mass to the drywell. |
Latest revision as of 04:45, 5 May 2021
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Category:SAFETY EVALUATION REPORT--LICENSING & RELATED ISSUES
MONTHYEARML20212C2921999-09-16016 September 1999 SER Accepting Licensee Request for Relief from ASME Code Section XI Requirements as Endorsed by 10CFR50.55a for Containment Insp for Pilgrim Nuclear Power Station ML20209C4731999-07-0707 July 1999 Addendum to SE on Proposed Transfer of Operating License & Matls License from Boston Edison Co to Entergy Nuclear Generation Co ML20196H2451999-06-29029 June 1999 SER Denying Licensee Proposed Alternative in Relief Request PRR-13,rev 2.Staff Determined That Proposed Alternative Provides Insufficient Info to Determine Adequacy of Scope of Implementation ML20209A8901999-06-28028 June 1999 SER Accepting Licensee Proposed Alternative to Use Code Case N-573 for Remainder of 10-year Interval Pursuant to 10CFR50.55a(a)(3)(i) ML20195K3431999-06-15015 June 1999 Safety Evaluation Granting Licensee Request to Use Guidance of GL 90-05 to Repair Flaws in ASME Class 3 Salt Svc Water System Piping for Plant ML20207E7471999-05-27027 May 1999 Safety Evaluation Granting Request Re Reduction of IGSCC Insp of Category D Welds Due to Implementation of HWC to License DPR-35 ML20206M1971999-05-11011 May 1999 SER Accepting Request for Approval to Repair Flaws in ASME Code Class 3 Salt Svc Water Piping at Plant ML20153D3901998-09-22022 September 1998 Safety Evaluation Granting 970707 Request to Use Guidance in GL 90-05 to Repair Flaws in ASME Class 3 Salt Svc Water Sys Piping for Pilgrim Nuclear Power Station ML20237E2251998-08-26026 August 1998 Suppl & Revs to SE for Amend 173 for Pigrim Nuclear Power Station ML20216J3741998-03-19019 March 1998 Safety Evaluation Accepting Licensee Request to Evaluate Elevated Tailpipe Temp on Safety Relief Valve SRV 203-3B ML20217D6431997-10-0101 October 1997 Safety Evaluation Granting Request for Approval to Repair Flaws in Accordance W/Gl 90-05 for ASME Class 3 SSW Piping for Pilgrim ML20137D0511997-03-20020 March 1997 Safety Evaluation Approving Third 10 Yr Interval ISI Program & Requests for Relief ML20134K2621997-02-10010 February 1997 Safety Evaluation Accepting Licensee one-time Request to Defer Insp of N2A & N2B safe-end Welds,Per GL 88-01 ML20129H3901996-10-30030 October 1996 Safety Evaluation Re Facility IPE Submittal for Internal Events & Internal Flood ML20129F4031996-09-27027 September 1996 Safety Evaluation Accepting Second ten-year Interval Inservice Insp Program Plan Request for Relief ML20059C3751993-12-29029 December 1993 Safety Evaluation Granting Exemption & Approving Alternative DAC Values for Use in Place of Generic Value for Radionuclides Specified in App B to 10CFR20.1001 - 20.2402 ML20058G2781993-11-29029 November 1993 Safety Evaluation Granting IST Program Relief Per 10CFR50.55a(f)(6)(i) & Approving Alternatives Per 10CFR50.55a(f)(4)(iv) ML20056F5301993-08-11011 August 1993 Safety Evaluation Re Licensee Response to Reg Guide 1.97, BWR Neutron Flux Monitoring. Criteria of NEDO-31558, Acceptable for Current BWR Operating License & Const Permit Holders ML20127P5431993-01-25025 January 1993 Safety Evaluation Supporting Amend 145 to License DPR-35 ML20126F8121992-12-23023 December 1992 Safety Evaluation Accepting Facility Design W/Respect to RG 1.97 ML20244C2901989-06-0606 June 1989 Draft Safety Evaluation of Util Compliance W/Atws Rule (10CFR50.62) Re Alternate Rod Injection & Recirculation Pump Trip Sys.Alternate Rod Injection Sys Not in Compliance W/Atws Rule Re Diversity ML20235V7341989-03-0303 March 1989 Safety Evaluation Accepting Util Revised Temp Profile,Per GE EAS-98-0887, Drywell Temp Analysis for Pilgrim Nuclear Power Station ML20154P6611988-09-28028 September 1988 SER Approving Rev 3 to Plant Second 10-yr Inservice Insp Program,Per 10CFR50.55a(g)(4) ML20151D0551988-07-18018 July 1988 Safety Evaluation Supporting Licensee Response to Generic Ltr 83-28,Item 2.2.1 Re Equipment Classification Programs for All safety-related Components ML20151E2041988-07-15015 July 1988 Safety Evaluation Supporting Incorporation of Reactor Protection Sys Circuitry Into Tech Specs & Deletion of 6- Month Channel Functional Test ML20154J9101988-05-17017 May 1988 Safety Evaluation Accepting Util Technical Evaluations & Acceptance Criteria Re Fire door-to-frame,frame-to-wall & Anchor Bolt Irregularities ML20155F8871988-03-24024 March 1988 Safety Evaluation Concluding That Internal Smoke Seals for Conduits Passing Through Fire Barriers from One Fire Area to Another Consistent W/Branch Technical Position 9.5-1 & Acceptable,Per Util 880203 Submittal ML20236Y3991987-11-10010 November 1987 SER Accepting Util Responses to Generic Ltr 83-28,Item 2.1, Part 1 Re Equipment Classification.Salp Input Encl ML20236V3081987-10-28028 October 1987 Safety Evaluation Supporting Acceptance of Offsite Dose Calculation Manual Updated Through Rev 1 on Interim Basis. App D to Technical Evaluation Rept EGG-PHY-7725 Encl ML20235M1611987-09-30030 September 1987 Safety Evaluation Supporting Util 870708 Proposed Change to Tech Specs Concerning LPCI Subsystem Testing ML20236Y3591987-07-22022 July 1987 Safety Evaluation Accepting Licensee Request to Modify Standby Liquid Control Sys Tech Specs,Per Requirements of ATWS rule,10CFR50.62.C.4.SALP Input Also Encl ML20206G8141987-03-26026 March 1987 Safety Evaluation Re Util Requests for Relief from Inservice Insp Requirements for Surface & Volumetric Exam of RHR Sys HX Nozzles & Exam of 100% Required Vol for nozzle-to-vessel Welds.Requests Granted W/Listed Conditions ML20215H9581987-03-17017 March 1987 Safety Evaluation Supporting Tech Spec Change Re Control Room High Efficiency Air Filter Sys.Salp Input Encl ML20212L8941987-01-15015 January 1987 Safety Evaluation Supporting Vacuum Breaker Analysis Performed to Predict Impact Velocities & Resulting Stresses ML20236Y3501986-09-0303 September 1986 Safety Evaluation Accepting Licensee 850813 Response Re Generic Ltr 83-28,Item 1.1 on post-trip Review.Salp Input Encl ML20212N8401986-08-22022 August 1986 SER Supporting Util Response to Item 1.C of NRC Re No Specific Time Limit Necessary on Containment Purging & Venting During Reactor Operation ML20155F8931986-08-20020 August 1986 Safety Evaluation Accepting Util 831116 Request for Four Exemptions from 10CFR50,App R,Section Iii.G.Level of Fire Safety in Listed Fire Zones Equivalent to Safety Achieved by Compliance W/Requirements ML20206L9511986-08-12012 August 1986 Safety Evaluation on Util Response to Generic Ltr 83-28, Items 3.1.1,3.1.2,.3.2.1,3.2.2 & 4.5.1 Re Maint & Test Procedures for safety-related Equipment & on-line Functional Testing of Reactor Trip Sys.Responses Acceptable ML20205C0621986-07-31031 July 1986 Safety Evaluation Accepting Util 831107 Response to Generic Ltr 83-28,Item 2.1, Post-Trip Review. BWR Parameter List Encl ML20236Y3361986-07-10010 July 1986 Safety Evaluation Supporting Util 831107 Response to Generic Ltr 83-28,Item 1.2 on post-trip Review & Data & Info Capability ML20199L2541986-07-0101 July 1986 Safety Evaluation Supporting Amend 96 to License DPR-35 ML20206D1741986-06-0606 June 1986 Safety Evaluation Supporting Util Response to IE Bulletin 80-11 Re Reevaluation & Testing Requirements in Items 2(b) & 3 Concerning Masonry Wall Design ML20203N3801986-04-30030 April 1986 Safety Evaluation Supporting Util 840625,1204,06,850521 & 1011 Responses to Generic Ltr 86-04 Concerning Recombiner Capability Requirements of 10CFR50.44(c)(3)(ii).Facility Does Not Require Recombiner Capability ML20236Y3711986-04-0101 April 1986 Safety Evaluation Accepting Util Response to Generic Ltr 83-28,Items 3.1.3 & 3.2.3 Re post-maint Testing of Reactor Trip Sys & All Other safety-related Components,Respectively. SALP Input Also Encl ML20137V7621986-02-12012 February 1986 SER Supporting Partial Relief from Generic Ltr 84-11 Re Performance of Visual Exam of Reactor Coolant Piping ML20135E5211985-09-11011 September 1985 Safety Evaluation Supporting post-trip Review Program & Procedures ML20134H3571985-08-13013 August 1985 Safety Evaluation Granting 821203,0804,831201,840628 & 850212 Relief Requests from ASME Code Requirements of Inservice Insp Program,Except for Items B9.10-B9.40 & C5.10-C5.32 Re Pressure Retaining Welds ML20140G1431985-07-0505 July 1985 Interim Safety Evaluation Supporting Util Response to Generic Ltr 83-36 Re NUREG-0737 Tech Specs ML20129C6901985-05-16016 May 1985 Safety Evaluation Re Dcrdr.Supplemental Rept Addressing Concerns Identified Necessary to Meet Requirements of NUREG-0737,Suppl 1 ML20206K6161985-03-13013 March 1985 SER Supporting Proposed Tech Spec Change to Permit Temporary Increase in Main Steam Line High Radiation Scram & Isolation Setpoints to Facilitate Testing of Hydrogen Addition Water Chemistry.Related Documentation Encl 1999-09-16
[Table view] Category:TEXT-SAFETY REPORT
MONTHYEARML20217E3021999-09-30030 September 1999 Monthly Operating Rept for Sept 1999 for Pilgrim Nuclear Station.With ML20212C2921999-09-16016 September 1999 SER Accepting Licensee Request for Relief from ASME Code Section XI Requirements as Endorsed by 10CFR50.55a for Containment Insp for Pilgrim Nuclear Power Station ML20216F3511999-09-0808 September 1999 ISI Summary Rept for Refuel Outage 12 at Pnps ML20216E6881999-08-31031 August 1999 Monthly Operating Rept for Aug 1999 for Pilgrim Nuclear Power Station.With ML20210R3401999-07-31031 July 1999 Monthly Operating Rept for July 1999 for Pilgrim Nuclear Power Station.With ML20209C4731999-07-0707 July 1999 Addendum to SE on Proposed Transfer of Operating License & Matls License from Boston Edison Co to Entergy Nuclear Generation Co ML20209H8251999-07-0101 July 1999 Provides Commission with Evaluation of & Recommendations for Improvement in Processes Used in Staff Review & Approval of Applications for Transfer of Operating Licenses of TMI-1 & Pilgrim Station ML20209E6191999-06-30030 June 1999 Monthly Operating Rept for June 1999 for Pilgrim Nuclear Power Station.With ML20196H2451999-06-29029 June 1999 SER Denying Licensee Proposed Alternative in Relief Request PRR-13,rev 2.Staff Determined That Proposed Alternative Provides Insufficient Info to Determine Adequacy of Scope of Implementation ML20209A8901999-06-28028 June 1999 SER Accepting Licensee Proposed Alternative to Use Code Case N-573 for Remainder of 10-year Interval Pursuant to 10CFR50.55a(a)(3)(i) ML20209B9861999-06-23023 June 1999 Rev 13A to Pilgrim Nuclear Power Station COLR for Cycle 13 ML20217N9061999-06-21021 June 1999 Rept of Changes,Tests & Experiments for Period of 970422-990621 ML20195K3431999-06-15015 June 1999 Safety Evaluation Granting Licensee Request to Use Guidance of GL 90-05 to Repair Flaws in ASME Class 3 Salt Svc Water System Piping for Plant ML20195G8231999-05-31031 May 1999 Monthly Operating Rept for May 1999 for Pnps.With ML20207E7471999-05-27027 May 1999 Safety Evaluation Granting Request Re Reduction of IGSCC Insp of Category D Welds Due to Implementation of HWC to License DPR-35 ML20206M1971999-05-11011 May 1999 SER Accepting Request for Approval to Repair Flaws in ASME Code Class 3 Salt Svc Water Piping at Plant ML20206J6611999-04-30030 April 1999 Monthly Operating Rept for Apr 1999 for Pilgrim Nuclear Power Station.With ML20205L0221999-03-31031 March 1999 Monthly Operating Rept for Mar 1999 for Pilgrim Nuclear Power Station.With ML20207J5471999-03-0909 March 1999 Training Simulator,1999 4-Yr Certification Rept ML20207F9401999-03-0101 March 1999 Long Term Program Semi-Annual Rept for Pilgrim Nuclear Power Station ML20207H5451999-02-28028 February 1999 Monthly Operating Rept for Feb 1999 for Pilgrim Nuclear Power Station.With ML20196E2151998-12-31031 December 1998 1998 Annual Rept for Boston Edison & Securities & Exchange Commission Form 10-K Rept.With ML20206Q2741998-12-31031 December 1998 Monthly Operating Rept for Dec 1998 for Pilgrim Nuclear Power Station.With ML20197J3591998-11-30030 November 1998 Monthly Operating Rept for Nov 1998 for Pilgrim Nuclear Power Station.With ML20195C9951998-10-31031 October 1998 Monthly Operating Rept for Oct 1998 for Pilgrim Nuclear Power Station.With ML20154K0721998-09-30030 September 1998 Monthly Operating Rept for Sept 1998 for Pilgrim Nuclear Power Station.With ML20153D3901998-09-22022 September 1998 Safety Evaluation Granting 970707 Request to Use Guidance in GL 90-05 to Repair Flaws in ASME Class 3 Salt Svc Water Sys Piping for Pilgrim Nuclear Power Station ML20197C5011998-09-0404 September 1998 Rev 12C,Pages 4 & 5 to Pilgrim Nuclear Power Station Colr ML20197C5471998-08-31031 August 1998 Rev 12C to Pilgrim Nuclear Power Station Colr ML20151W8231998-08-31031 August 1998 Monthly Operating Rept for Aug 1998 for Pilgrim Nuclear Power Station.With ML20237E2251998-08-26026 August 1998 Suppl & Revs to SE for Amend 173 for Pigrim Nuclear Power Station ML20237A9941998-07-31031 July 1998 Monthly Operating Rept for Pilgrim Nuclear Power Station ML20236U8201998-07-13013 July 1998 Rev 12B to Pilgrim Nuclear Power Station COLR (Cycle 12) ML20236P0151998-06-30030 June 1998 Monthly Operating Rept for June 1998 for Pilgrim Nuclear Power Station ML20249A3741998-05-31031 May 1998 Monthly Operating Rept for May 1998 for Pilgrim Nuclear Power Station.W/Undated Ltr ML20247H2081998-04-30030 April 1998 Monthly Operating Rept for Apr 1998 for Pilgrim Nuclear Power Station ML20207B7601998-03-31031 March 1998 Final Rept, Pilgrim Nuclear Power Station Site-Specific Offsite Radiological Emergency Preparedenss Prompt Alert & Notification System Quality Assurance Verification, Prepared for FEMA ML20216G3911998-03-31031 March 1998 Monthly Operating Rept for Mar 1998 for Pilgrim Nuclear Power Station ML20216J3741998-03-19019 March 1998 Safety Evaluation Accepting Licensee Request to Evaluate Elevated Tailpipe Temp on Safety Relief Valve SRV 203-3B ML20248L2241998-02-28028 February 1998 Monthly Operating Rept for Feb 1998 for Pilgrim Nuclear Station ML20202G5251998-01-31031 January 1998 Monthly Operating Rept for Jan 1998 for Pilgrim Nuclear Power Station ML20236M8511997-12-31031 December 1997 1997 Annual Rept for Boston Edison & Securities & Exchange Commission Form 10-K Rept ML20198L7701997-12-31031 December 1997 Monthly Operating Rept for Dec 1997 for Pilgrim Nuclear Power Station ML20203D6101997-11-30030 November 1997 Monthly Operating Rept for Nov 1997 for Pilgrim Nuclear Power Station ML20202D5761997-11-0808 November 1997 1997 Evaluated Exercise BECO-LTR-97-111, Monthly Operating Rept for Oct 1997 for Pilgrim Nuclear Power Station1997-10-31031 October 1997 Monthly Operating Rept for Oct 1997 for Pilgrim Nuclear Power Station ML20217D6431997-10-0101 October 1997 Safety Evaluation Granting Request for Approval to Repair Flaws in Accordance W/Gl 90-05 for ASME Class 3 SSW Piping for Pilgrim ML20217H5621997-09-30030 September 1997 Monthly Operating Rept for Sept 1997 for Pilgrim Nuclear Power Station ML20216J4131997-08-31031 August 1997 Monthly Operating Rept for Aug 1997 for Pilgrim Nuclear Power Station ML20210J3321997-07-31031 July 1997 Monthly Operating Rept for Jul 1997 for Pilgrim Nuclear Power Station 1999-09-08
[Table view] |
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e jourg4; UNITED STATES
. !. n NUCLEAR REGULATORY COMMISSION
$ .E WASHINGTON, D. C. 20555
%,...../
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGt!LATION RELATING TO THE TIME LIMIT ON CONTAINMENT VENTING AND PilRGING BOSTON EpISON COMPANY PILGRIM NtlCLEAR POWER STATION p0CKET NO. 50-293
1.0 INTRODUCTION
In a letter to the licensee dated November 29, 1978, the staff identified two areas of concern associated with operation of the containment vent and purge valves while the plant is at power. The concerns relate to the following possible events: 1) a LOCA occurring while the isolation signals for opening the purge / vent valves are overridden, and 2) a LOCA occurrina durina purge / vent valve operations. Both of these events could produce unacceptable radioactive releases. The letter requested the licensee to propose a technical specifica-tion either to prohibit venting and purging during onwer operation or to limit the venting and purging operations to 90 hours0.00104 days <br />0.025 hours <br />1.488095e-4 weeks <br />3.4245e-5 months <br /> per year with adequate justifi-cation. As an alternative, the licensee could provide justification for unlimited usage of the vent and purge lines. In response to the letter, the licensee provided information concerninc the operation of their vent and purge valves. On the basis of that informaticn, the staff issued safety evaluations (SE) on April 11 and September 24, 198/. These SEs indicated that the licensee's approach was acceptable, pending receipt of adequate justification for not requiring a vent and purge time limitation.
By letters dated April 1, 1985 and October 23, 1985, the licensee submitted additional information supporting its proposal not to have any operational limitation on use of the vent and porce valves during power operation. This evaluation deals with the acceptability of that proposal. ,
2.0 EVAltlATION The April 1,1985 letter provided the results of a licensee LOCA dose analysis for the 20-inch vent and purge valves. The analysis assumed the following l
( conditions:
- A large pipe break inside the containment instantaneously releases the entire primary coolant mass to the drywell.
- No core damage or fuel perforation for the first 17 seconds. '
l
~
f 8608290202 860922 PDR ADOCK 05000293 P
PDR
- The entire prirary coolant inventory of noble pases and iodine, including spiking, is released to the drywell and becomes airborne.
No credit is given for plateout.
~
- The release of the drywell atmosphere activity is via the reactor building vent, yielding an unfiltered ground level release to the environment prior to drywell isolation.
- The release is, at a rate of .323 Mlbs/hr, directly to the environment.
The results of the analysis indicate that the 2-hour site boundary dose to the thyroid would be 40.6 rem, with a whole body aamma dose of 1.34 rem and a beta and gamma skin dose of 5.80 rem. The licensee's analysis is in conformance with the dose assessment guidelines of Position B.5.a of NRC Branch Technical Position CSB 6-4, " Containment Purgina During Normal Plant Operations." The offsite doses are less than those identified in 10 CFR Part 100. Furthermore, the licensee has replaced the 70-inch valves ir the vent and ourge lines with 8-inch valves which are fully qualified to close under the LOCA conditions.
The use of S-inch valves is in conformance with Position B.I.c of the Branch Technical Position CSB 6-4.
The forces associated with the LOCA conditions will not fail the ductwork to the SGTS. Hence, the SGTS can be assumed to be available. The availability of the SGTS will reduce further the offsite doses such that the need for limiting i the operational time for the vent and purge valves does not exist. Our review indicates the licensee's assessment of such ar. accident is reasonable and satisfies Position B.S.a of Branch Technical Position CSB 6 a.
While the number of hours per year of operation of the vent and purge valves has not been specifically limited, there are other constraints which will effectively minimize the coeration of these valves. For example, 10 CFR 50.44(c)(3)(i) requires all BWRs to have inerted containments. Pilgrim Technical Specification 3.7.A.1.1 requires that a pressure differential be maintained between the torus and the drywell. In addition, Technical Specifi-cation 3.7.A.5.a states that the primary contai_nment atmosphere shall be reduced to less than 4% o'jgen by volume with nitrogen gas durina reactor power operation with the reactor coolant pressure above 100 psig, except as specified in 3.7.A.S.b. Technical Specification 3.7.A.S.b provides a limit of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> after placing the reactor in the run mode to reduce the oxygen content to less than 4% and also allows the de-inerting to commence 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> prior to shutdown. On the basis of these restraining items, there is reasonable assurance that the number of hours when the vent and purge valves will be used during power operation will be minimized. Therefore, the staff concludes the likelihood of a design basis LOCA resulting in an accident producing a release as severe as discussed in Regulatory Guide 1.3, while venting and purging, is sufficiently low that it need not be considered for this evaluation. Hence, the licensee's request to eliminate any operational time limit on these valves is acceptable. l l
t i
l
3.0 CONCLUSION
We conclude that there is no need to impose a 90-hour limitation on the operation of the vent and purge valves at Pilgrim for the followino reasons:
- 1) The offsite deses predicted for a LOCA while purging are within the reouire-ments of 10 CFR Part 100; 2) Installation of the 8-inch valves in the 20-inch purge lines assures the availability of the SGTS to further reduce the offsite consequences; and 3) the present te-hnical specifications limiting the oxygen in the primary containment provide assurance that the number of hours of vent and purge operations will be minimized.
Principal Reviewer: .1. Ridgely Dated: August 22, 1986 t
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