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Category:SAFETY EVALUATION REPORT--LICENSING & RELATED ISSUES
MONTHYEARML20210Q0521999-08-0404 August 1999 Safety Evaluation Approving Relief Request 10 to License DPR-22 Per 10CFR50.55a(g)(6)(i).Inservice Exam for Relief Request 10,Parts A,B,C,D & E Impractical & Reasonable Assurance of Structural Integrity Provided ML20205N0861999-04-12012 April 1999 Safety Evaluation Re Licensee Response to GL 95-07, Pressure Locking & Thermal Binding of Safety-Related Power-Operated Gate Valves ML20204H4951999-03-18018 March 1999 SER Concluding That Licensee Established Acceptable Program to Verify Periodically design-basis Capability of safety-related MOVs at Monticello.Therefore Staff Concludes Licensee Adequately Addressed Action Required in GL 96-05 ML20199E4871999-01-0606 January 1999 SER Accepting Licensee 951116,960214 & 0524 Responses to NRC Bulletin 95-002, Unexpected Clogging of Residual Heat Removal Pump Strainer While Operating in Suppression Pool Cooling Mode ML20198P0691998-12-28028 December 1998 Safety Evaluation Concluding That NSP Proposed Alternative to Paragraph III-3411 of App III to 1986 Edition of Section XI of ASME Code Provides Acceptable Level of Quality & Safety.Alternative Authorized ML20198D0751998-12-10010 December 1998 Safety Evaluation Supporting NSP Proposed Change to EOPs to Use 2/3 Core Height as Potential Entry Condition Into Containment Flooding ML20195E3691998-11-12012 November 1998 Safety Evaluation Concluding That Licensee USI A-46 Implementation Has Met Purpose & Intent of Criteria in GIP-2 & Staff Sser 2 for Resolution of USI A-46 ML20199G7051997-11-19019 November 1997 Safety Evaluation Authorizing Relief Request 8 of Third 10 Yr Inservice Insp Interval ML20059C4051993-10-25025 October 1993 Safety Evaluation Re Inservice Testing Program Relief Requests GR-7 & RCIC-6 for Plant.Proposed Alternative to OM-1 Safety & Valve Relief Valve Requirements Authorized Based on Alternative Providing Acceptable Level of Quality ML20128Q6511985-07-0303 July 1985 Safety Evaluation Re Item 1.1 of Generic Ltr 83-28, Post-Trip Review. Review Program & Procedures Acceptable ML20148N4711978-11-0606 November 1978 Safety Eval Supporting Amend 37 to Provisional Oper Lic DPR-22.Concludes Issuance of Amend Will Not Be Inimical to Nation or People ML20126C1921977-03-0808 March 1977 SER Accepting Proposed Pumpback Sys for Plant ML20128E0801976-08-26026 August 1976 Safety Evaluation Supporting Amend to License DPR-22,re Proposed Interim Program for Offsite Shipment of Spent Fuel ML20127P4091976-07-25025 July 1976 Safety Evaluation Re Amend to License DPR-22,proposing Shipment of Sf from Monticello Nuclear Generating Plant Using GE IF-300 Shipping Cask ML20128D9621976-05-27027 May 1976 Safety Evaluation Supporting Amend 19 to License DPR-22. Amend Changes Involved Reduction in MSL Low Pressure Isolation Setpoint & Reduction in MCPR for 8x8 & 7x7 Fuel ML20126C1771976-04-0202 April 1976 SER Accepting Util Request for Change in Main Steam Isolation Pressure Setpoint Value & Operating Min Critical Power Ratio Limits ML20125A4521975-09-30030 September 1975 Safety Evaluation of Plant Conformance to Requirements of App K to 10CFR50 & Acceptability of Proposed GETAB-based TS ML20127K4141975-09-15015 September 1975 Safety Evaluation Accepting Amend 12/change 20 to DPR-22 Changing Hydraulic Snubber TS ML20127H2311975-07-15015 July 1975 Safety Evaluation Accepting TS Changes Proposed in Re Suppression Pool ML20127K2411975-07-0808 July 1975 Safety Evaluation Accepting Increased Limitations of U-235 ML20127K3281975-04-10010 April 1975 SER Accepting Amend 9/change 18 to DPR-22 Correcting Typos ML20127J5131975-02-0303 February 1975 Safety Evaluation Accepting Amend 7 (TS Change 16) to DPR-22 Re Reactor Vessel Matl Surveillance Program ML20128E0551974-10-16016 October 1974 Suppl Safety Evaluation Supporting License DPR-22 Re Full Term Operating License Application ML20127J6381974-08-20020 August 1974 Safety Evaluation Accepting Amend 6 to DPR-22 Re Use of 250 Mci Kr-85 ML20127M8571974-05-14014 May 1974 Safety Evaluation Accepting Use of 8x8 Fuel ML20127G6501974-03-30030 March 1974 Safety Evaluation Accepting Loading of 8x8 Fuel Assemblies in Core ML20127G6211974-03-14014 March 1974 Safety Evaluation Accepting 740123 Proposed Changes During Refueling Outage ML20127G6661973-11-27027 November 1973 Safety Evaluation Accepting Proposed Changes Re Reactivity ML20128D8411973-11-27027 November 1973 SER Accepting Util 720922 Request for Change to TS Re Rod Drop Accident ML20127J5461973-11-15015 November 1973 Safety Evaluation Accepting 731026 & 31 Proposed Changes to TS Re off-gas Holdup Sys ML20127G6941973-10-18018 October 1973 Safety Evaluation Accepting Removal of Stated Control Rod Inventory Restriction ML20127G7121973-10-0202 October 1973 Safety Evaluation Accepting Increase in Safety Valve Set Points,Per 730913 Request to Change TS ML20127N7601973-08-24024 August 1973 Safety Evaluation of Fuel Densification Effects on Plant ML20127M7511972-01-14014 January 1972 Safety Evaluation Accepting Proposed Change 2 to DPR-22 TS Re Gaseous Radwaste Sys Design ML20127N6411970-03-30030 March 1970 Suppl 1 to SE in Matter of NSP Monticello Nuclear Generating Plant Unit 1 1999-08-04
[Table view] Category:TEXT-SAFETY REPORT
MONTHYEARML20217D1261999-09-30030 September 1999 Monthly Operating Rept for Sept 1999 for Monticello Nuclear Generating Plant.With ML20216E7031999-08-31031 August 1999 Monthly Operating Rept for Aug 1999 for Monticello Nuclear Generating Plant.With ML20210Q0521999-08-0404 August 1999 Safety Evaluation Approving Relief Request 10 to License DPR-22 Per 10CFR50.55a(g)(6)(i).Inservice Exam for Relief Request 10,Parts A,B,C,D & E Impractical & Reasonable Assurance of Structural Integrity Provided ML20210Q6611999-07-31031 July 1999 Monthly Operating Rept for July 1999 for Monticello Nuclear Generating Plant.With ML20209F7901999-06-30030 June 1999 Monthly Operating Rept for June 1999 for Monticello Nuclear Generating Plant.With ML20195H0351999-05-31031 May 1999 Monthly Operating Rept for May 1999 for Monticello Nuclear Generatintg Plant.With ML20206N1721999-04-30030 April 1999 Monthly Operating Rept for Apr 1999 for Monticello Nuclear Generating Plant.With ML20205N0861999-04-12012 April 1999 Safety Evaluation Re Licensee Response to GL 95-07, Pressure Locking & Thermal Binding of Safety-Related Power-Operated Gate Valves ML20205P5701999-03-31031 March 1999 Monthly Operating Rept for Mar 1999 for Monticello Nuclear Generating Plant.With ML20204H4951999-03-18018 March 1999 SER Concluding That Licensee Established Acceptable Program to Verify Periodically design-basis Capability of safety-related MOVs at Monticello.Therefore Staff Concludes Licensee Adequately Addressed Action Required in GL 96-05 ML20205G7391999-02-28028 February 1999 Monthly Operating Rept for Feb 1999 for Monticello Nuclear Generating Plant.With ML20202F7901999-01-25025 January 1999 1999 Four Year Simulator Certification Rept for MNGP Simulation Facility ML20199E4871999-01-0606 January 1999 SER Accepting Licensee 951116,960214 & 0524 Responses to NRC Bulletin 95-002, Unexpected Clogging of Residual Heat Removal Pump Strainer While Operating in Suppression Pool Cooling Mode ML20199F6211998-12-31031 December 1998 Monthly Operating Rept for Dec 1998 for Mngp.With ML20205H0561998-12-31031 December 1998 Northern States Power Co 1998 Annual Rept. with ML20198P0691998-12-28028 December 1998 Safety Evaluation Concluding That NSP Proposed Alternative to Paragraph III-3411 of App III to 1986 Edition of Section XI of ASME Code Provides Acceptable Level of Quality & Safety.Alternative Authorized ML20198D0751998-12-10010 December 1998 Safety Evaluation Supporting NSP Proposed Change to EOPs to Use 2/3 Core Height as Potential Entry Condition Into Containment Flooding ML20198B2531998-11-30030 November 1998 Monthly Operating Rept for Nov 1998 for Monticello Nuclear Generating Plant.With ML20195E3691998-11-12012 November 1998 Safety Evaluation Concluding That Licensee USI A-46 Implementation Has Met Purpose & Intent of Criteria in GIP-2 & Staff Sser 2 for Resolution of USI A-46 ML20195D2381998-10-31031 October 1998 Monthly Operating Rept for Oct 1998 for Monticello Nuclear Generating Plant.With ML20198J4451998-10-22022 October 1998 Rev 2 to SIR-97-003, Review of Test Results of Two Surveillance Capsules & Recommendations for Matls Properties & Pressure-Temp Curves to Be Used for Monticello Rpv ML20154L3471998-09-30030 September 1998 Monthly Operating Rept for Sept 1998 for Monticello Nuclear Generating Plant.With ML20153F0511998-09-21021 September 1998 Rev 2 to MNGP Colr,Cycle 19 ML20153E9361998-09-0808 September 1998 Rev 1 to MNGP Colr,Cycle 19 ML20153B0861998-08-31031 August 1998 Monthly Operating Rept for Aug 1998 for Monticello Nuclear Generating Plant.With ML20237B8461998-07-31031 July 1998 Monthly Operating Rept for July 1998 for Monticello Nuclear Generating Plant ML20236W5041998-07-21021 July 1998 ISI Exam Summary Rept - Refueling Outage 19 ML20236R1941998-06-30030 June 1998 Monthly Operating Rept for June 1998 for Monticello Nuclear Generating Plant ML20249A5861998-05-31031 May 1998 Monthly Operating Rept for May 1998 for Monticello Nuclear Generating Plant ML20247K3971998-04-30030 April 1998 Monthly Operating Rept for Apr 1998 for Monticello Nuclear Generating Plant ML20217D8731998-04-13013 April 1998 Rev 0 to MNGP Colr,Cycle 19 ML20217F6431998-03-31031 March 1998 Monthly Operating Rept for Mar 1998 for Monticello Nuclear Generating Plant ML20216D1041998-03-0505 March 1998 Rev 21 to Operational QA Plan ML20216H6481998-02-28028 February 1998 Monthly Operating Rept for Feb 1998 for Monticello Nuclear Generating Plant ML20203G1431998-02-10010 February 1998 Rev 2 to Inservice Insp Exam Plan,Third Interval,920601- 020531 ML20203B2821998-01-31031 January 1998 Monthly Operating Rept for Jan 1998 for Monticello Nuclear Generating Station ML20202F9161998-01-29029 January 1998 Special Rept:On 980128,two of Three Fire Protection Pumps Were Removed from Svc as Result of Sys Configuration Necessary to Support Planned Maintenance.Fire Pumps Were Returned to Svc on 980128 ML20216D2071997-12-31031 December 1997 1997 Annual Rept for Northern States Power Co ML20197J8131997-12-31031 December 1997 Revised Evacuation Time Estimates for Plume Exposure Pathway Emergency Planning Zone at Monticello Nuclear Power Plant. W/One Oversize Drawing ML20198P2201997-12-31031 December 1997 Monthly Operating Rept for Dec 1997 for Monticello Nuclear Generating Plant ML20203J7131997-11-30030 November 1997 Monthly Operating Rept for Nov 1997 for Monticello Nuclear Generating Plant ML20199G7051997-11-19019 November 1997 Safety Evaluation Authorizing Relief Request 8 of Third 10 Yr Inservice Insp Interval ML20199H8181997-10-31031 October 1997 Monthly Operating Rept for Oct 1997 for Monticello Nuclear Generating Plant ML20217K2081997-09-30030 September 1997 Monthly Operating Rept for Sept 1997 for Monticello Nuclear Generating Plant ML20216H7771997-08-31031 August 1997 Monthly Operating Rept for Aug 1997 for Monticello Nuclear Generating Plant ML20217K2741997-07-31031 July 1997 Monthly Operating Rept for Jul 1997 for Monticello Nuclear Generating Plant ML20196H1081997-07-0808 July 1997 Rev 20 to Operational QA Plan ML20141B9271997-06-30030 June 1997 LOCA Containment Analyses for Use in Evaluation of NPSH for RHR & Core Spray Pumps ML20149E2921997-06-30030 June 1997 Monthly Operating Rept for June 1997 for MNGP ML20148S6341997-06-23023 June 1997 NPSH - Rept of Sulzer Bingham Pump 1999-09-30
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> l SAFETY EVALUATION BY-WE OFFICE OF NUCLEAR REACIOR REGUIATION ON WE PROP 05tu PUMPBACK SYdiud FOT K NFICELLO NUCLEAR P0hER STATION D0atil NO. 50-263 -
Ba'kground c
As a result of recent stmetural analyses perfomed in conjunction.
with a generic review of pool dynamic loads for Mark I pressure - suppression containments, it was determined that the consideration of pool dynamic loads resulting from a postulated loss-of-coolant accident had reduced the margin of safety in the containment design for.the Manticello Nuclear Power Station. Subsequently, the licensee agreed to institute a " differential pressure control system".to mitigate the pool dynamic loads and thereby restore the margin of safety in the containment design. The differential pressure control system establishes a positive pressure between the drywell and torus regions of the containment which reduces :the height of the water leg in the downcomers and subsequently reduces the hydrodynamic loads.
To control combustible gases following a postulated loss-of-coolant accident,=the containment atmosphere is inerted with nitrogen during normal operation. The inclusion of a positive differential pressure between the-drywell and torus results in a loss of nitrogen from the drywell to the .
j torus airspace from leakage through the vacuum breakers on the vent headers. To minimize the loss of_ nitrogen from the system, the licensee has proposed a "pumpback" system which would collect the over-inerted atmosphere in the torus and return it _to .the drywell.
l 4
9212220412 770308 PDR ADOCK 05000263 p PDR
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System Description
1he pumpback system consists of a two inch line which is welded into the existing toms vent bypass line and the drywell atmosphere purge line. The pumpback line takes suction from the torus vent bypass line and branches into two parallel flow paths, each containing an upstream shutoff valve, a 1001, capacity blower, a check valve, and a downstream shutoff valve in series. The parallel lines rejoin and discharge into the drywell atmosphere purge line. The existing isolation valves on both the toms vent bypass and the drywell atmosphere purge line have been changed from a nomally closed position to a normally open position to provide the flow path from the torus airspace to the drywell.
Safety Evaluation The installation of the proposed pumpback system has required the addition of a control valve on the torus vent bypass line to provide the proper containment isolation capability. The new isolation valve, designated CV-7440, is installed in series with an existing control valve, designated CV-2384, to provide redundant containment isolation capability. The outboard isolation valve, CV-7440, is an air operated valve which is open when the valve solenoid is energized and will close' upon the receipt of a Group 2 isolation signal, the loss of the instrument bus associated with the outboard isolation valves, or the loss of instrument air. The inboard isolation valve, CV-2384, receives power from a separate instrument bus, and similarly will close uyn loss of its instrument bus, on loss of instrument air or upon receipt of a Group 2 isolation signal. The position of both valves will be indicated in the control room, i
p '
, s _._
i . . .
4 and the valves will be leak tested in accordance with Appendix J to -
l 10 CFR 50.
4 i
- We have also_ reviewed other potential effects the inclusion of the h
l pumpback systs could have on the consequences of a postulated loss-of-4-
coolant accident. Potential steam bypass of the suppression pool could i
j result- from the direct comunication of the drywell and the torus air
- space. However, the low mass flow rate associated with the 2 inch size j -line in conjunction with the redundant capability to isolate both the l torus vent bypass line-and the drywell atmosphere purge line will result
- i. in a negligible amount of steam bypass. In addition, a swing-disk check
?
! valve, located down stream of the blower, which would prevent reverse a
j flow rom f the drywell and further mitigate the effects of steam bypass.
1
- ' Conclusion
. We have reviewed the proposed pumpback syst m for the Monticello Nuclear Power Station with regard to both containment isolation capability h and potential adverse effects on a postulated loss-of-coolant accident.
The licensee has provided both redundant and diverse isolation capability in conjunction with the existing isolation valves and the added isolation--
valve, CV-7440. In addition, the installation of the punback system ,
will neither increase the probability of an occurrence, nor will_ it increase t
the consequences of a postulated accident. Therefore, we conclude that pumpback system,.as proposed by the licensee, is acceptable.
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