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Category:CORRESPONDENCE-LETTERS
MONTHYEARML20217M8771999-10-25025 October 1999 Requests That Industry Studies on long-term Spent Fuel Pool Cooling Be Provided to R Dudley at Listed Mail Stop ML20217M4331999-10-19019 October 1999 Submits Rept 17, Requal Tracking Rept from Operator Tracking Sys. Rept Was Used by NRC to Schedule Requalification Exams for Operators & Record Requal Pass Dates ML20217F5841999-10-13013 October 1999 Requests Revocation of License OP-11038-1 for GE Kingsley. Individual Has Been Reassigned to Position within Naesco ML20217F5811999-10-13013 October 1999 Forwards Insp Data & Naesco Evaluation of a EDG Exhaust Insp Conducted on 990407.Insp Ensured That Unacceptable Wall Thinning Will Not Occur During 40-year Design Lifetime of Sys ML20217C7321999-10-0808 October 1999 Forwards Copy of Seabrook Station Videotape Entitled, Completion of Seal Barrier Installation. Videotape Documents Process of Selecting,Designing & Installing Seal Deterrent Barrier to Preclude Entrapment of Seals ML20217B8621999-10-0505 October 1999 Forwards Rev 28,change 1 to EPIP Er 1.1, Classification & Emergencies, Per 10CFR50.54(q).Rev to Procedure Does Not Decrease Effectiveness of Seabrook Station Radiological Emergency Plan ML20217B7471999-10-0101 October 1999 Provides Notification of Change in PCT of More than 50 F,Per Requirements of 10CFR50.46(a)(3)(i),(ii).Tabulation of Large Break LOCA PCT Margin Utilization Applicable to Seabrook Station,Encl ML20212J8271999-09-30030 September 1999 Informs of Completion of mid-cycle PPR of Seabrook Station. Staff Conducted Reviews for All Operating NPPs to Integrate Performance Info & to Plan for Insp Activities at Facility Over Next Six Months.Plant Issues Matrix & Insp Plan Encl ML20216J2381999-09-30030 September 1999 Responds to Re Enforcement Discretion for Nuclear Plants During Y2K Transition.Nrc Expects All Licensees to Operate Nuclear Facilities Safety IAW NRC Regulations & Requirements ML20216J2421999-09-30030 September 1999 Responds to Card Received in Aug 1999,providing Comments on NRC Interim Enforcement Policy Re Enforcement Discretion for Nuclear Plants During Y2K Transition.Informs That Naesc Reported Seabrook as Y2K Ready Prior to 990701 ML20216J2471999-09-30030 September 1999 Responds to Which Provided Comments on NRC Interim Enforcement Policy Re Enforcement Discretion for Nuclear Plants During Y2K Transition.Informs That Naesc Reported Seabrook as Y2K Ready Prior to 990701 ML20212K7921999-09-30030 September 1999 Confirms 990922 Telcon with J D'Antonio & T Grew Re Arrangements Made for NRC to Inspect Licensed Operator Requalification Program at Seabrook Facility ML20212J0301999-09-24024 September 1999 Forwards Insp Rept 50-443/99-10 on 990726-30 & 0809-13.No Violations Noted.Insp Discussed ML20212G5071999-09-21021 September 1999 Submits Complaint to NRC Re NRC Failure to Cite Seabrook Station NPP Operators for Failing to Periodically Calibrate & Establish Adequate Measures to Insure That Relay Equipment Met All Required Calibration Settings Prior to Installation ML20212C1881999-09-20020 September 1999 Ack Receipt of Which Raised Concerns Re NRC Enforcement Actions at Plant & Issuance of NCVs ML20212D1401999-09-17017 September 1999 Forwards SE Accepting Request to Use Proposed Alternative to Certain Weld Repair Requirements in ASME Boiling & Pressure Vessel Code ML20212B9511999-09-17017 September 1999 Forwards NRC Form 396 for MG Sketchley,License SOP-10685, Along with Supporting Medical Exam Info.Nrc Form 396 Has Been Superceded by Revised Version Dtd 971222,which Was Previously Submitted to NRC on 990812.Encl Withheld ML20212C3621999-09-15015 September 1999 Forwards Rev 34 to Seabrook Station Radiological Emergency Plan & Rev 85 to Seabrook Station Emergency Response Manual, Per 10CFR50,App E & 10CFR50.4 ML20212B5021999-09-14014 September 1999 Forwards Licensee Responses to EPA Questions Re Plant Seal Deterrent Barrier.Util Completed Installation of Subject Barriers on All Three Station Offshore Intake Structures on 990818.Barriers Will Preclude Entrapment of Seals ML20211Q8521999-09-0808 September 1999 Informs That Rl Couture,License SOP-11027,terminated Employment at Naesco on 990907.Revocation of License Requested ML20211N8781999-09-0303 September 1999 Forwards Response to 990820 RFI Re NRC Administrative Ltr 99-03, Preparation & Scheduling of Operator Licensing Exams ML20211J9291999-09-0303 September 1999 Forwards mark-ups & Retypes of Proposed Conforming License Changes Required in Connection with Transfers Being Sought in 990615 Application of Montaup Electric Co & New England Power Co for Transfer of Licenses & Ownership Interests ML20211M3221999-09-0202 September 1999 Responds to NRC Re Violations Noted in Insp of License NPF-86 & Proposed Imposition of Civil Penalty. Corrective Actions:Conducted Prompt Review of Layoff Decision to Determine Relevant Facts DD-99-10, Informs That Time Provided by NRC Regulation within Which Commission May Act to Review Director'S Decision (DD-99-10) Expired.Commission Declined Review & Decision Became Final on 990830.With Certificate of Svc.Served on 9909021999-09-0202 September 1999 Informs That Time Provided by NRC Regulation within Which Commission May Act to Review Director'S Decision (DD-99-10) Expired.Commission Declined Review & Decision Became Final on 990830.With Certificate of Svc.Served on 990902 ML20211J8811999-09-0101 September 1999 Forwards Comments on Seabrook Station Review of Reactor Vessel Integrity Database (Rvid)(Version 2).Minor Discrepancies Were Noted.Proposed Changes Are Encl in Order to Correct Discrepancies ML20211J8411999-09-0101 September 1999 Forwards Updated NRC Form 396 for E Decosta,Nrc License OP-10655-1.Without Encl ML20211G9191999-08-27027 August 1999 Informs NRC That Name of New Company, Ref in Order Approving Application Re Corporate Merger Is Nstar Which Is Massachusetts Business Trust ML20211J0401999-08-26026 August 1999 Responds to 990819 Request,On Behalf of Gr Pageau & Williams Power Corp,For Addl Time in Which to Reply to Nov,Issued on 990803.Response Due to NRC by 991008 ML20211H0651999-08-25025 August 1999 Forwards Insp Rept 50-443/99-05 on 990621-0801.One Violation Re Failure to Include Multiple Components within Scope of ISI Test Program Was Identified & Being Treated as NCV, Consistent with App C of Enforcement Policy ML20211G7761999-08-24024 August 1999 Expresses Great Concern Re Lack of Enforcement Actions Against Seabrook Station Despite Citations NRC Has Issued for Violations of Seabrook Operating License ML20211J2171999-08-23023 August 1999 Expresses Disappointment with Lack of Enforcement Action Against Seabrook Station Despite Repeated Safety Violations ML20211J4971999-08-21021 August 1999 Submits Comments Re Violations Cited in Early Mar & 990509 Insps ML20211H8361999-08-19019 August 1999 Submits Concerns Re Violations at Seabrook Station ML20211F2681999-08-19019 August 1999 Discusses Former Chairman Jackson & 990602 Predecisional Enforcement Conference Re Findings of Ofc of Investigations Involving Allegations Raised by Contract Electrician.Determined That Allegations Not Supported ML20211J3241999-08-15015 August 1999 Expresses Disappointment in Apparent Failure of NRC to Cite Seabrook Station NPP for Recent Violations of Safety Regulations Uncovered During Recent Insps in Mar & May ML20211J1831999-08-15015 August 1999 Submits Concerns Over Serious Deficiencies at Seabrook Station That NRC Has Declined to Take Enforcement Actions Against ML20210T1601999-08-13013 August 1999 Informs That as Result of Staff Review of Licensee Responses to GL 92-01,rev,supp1 1, Reactor Vessel Structural Integrity, NRC Revised Info in Reactor Vessel Integrity Database & Is Releasing It as Rvid Version 2 ML20211J2071999-08-13013 August 1999 Expresses Concerns Re Violations Occurring Recently at Seabrook Nuclear Power Station.Requests Effort to See That Measures Taken to Stop Flagrant,Continuing Violations That Hold Danger to Workers & Community ML20210S9611999-08-13013 August 1999 Informs That NRC Received Encl Ltr from Pb Johnston Expressing Concern About Certain Impacts on Shareholders of New England Electric Sys with Respect to Nees Proposed Merger with Natl Grid Group ML20210S9511999-08-13013 August 1999 Responds to to Collins Expressing Concerns with Certain Terms of Proposed Merger Between New England Electric Sys & National Grid Group.Nrc Has No Authority to Interject Itself in Nees Merger with National Grid Group ML20210S2001999-08-12012 August 1999 Forwards NRC Forms 398 & 396 in Support of Applications for Renewal of Operator Licenses for Individuals Listed Below. Without Encls ML20210R8401999-08-11011 August 1999 Forwards Response to NRC Second RAI Re GL 95-07, Pressure Locking & Thermal Binding of SR Power-Operated Gate Valves ML20210S7331999-08-11011 August 1999 Submits Third Suppl to 980423 Application to Renew NPDES Permit NH0020338 for Seabrook Station.Suppl Provides Addl Info on Input Streams & Requests Increased Permit Limit for Chemical Used in Makeup Water Treatment Sys ML20210R9581999-08-11011 August 1999 Forwards ISI Exam Rept of Seabrook Station, for RFO 6, Period 3,for Insps Conducted Prior to & During Sixth Refueling Outage Concluded on 990510 ML20210Q7441999-08-11011 August 1999 Forwards Order Approving Indirect Transfer of Control of Canal Interest in Seabrook Station Unit 1 as Requested in Application & SER ML20210R7931999-08-10010 August 1999 Forwards Cycle 7 Startup Rept for Seabrook Station, IAW Requirements of TS 6.8.1.1 ML20210N9421999-08-0505 August 1999 Informs That North Atlantic Suggests Listed Revisions to 990730 Draft Revisions to Committee Rept & Order.Further Revs Consistent with What North Atlantic Proposed at 990608 Hearing ML20210N5721999-08-0303 August 1999 Discusses Investigations Rept 1-98-005 Conducted by OI at Naesco,Seabrook Station & Forwards NOV & Proposed Imposition of Civil Penalty - $55,000.Violation Re Failure to Promptly Correct Incorrectly Terminated Cables of Control Bldg Air ML20210P3361999-08-0303 August 1999 Discusses Investigation Rept 1-98-005 Conducted by Region I OI at Naesco,Seabrook Station & Forwards Nov.Violations Re Electrical Wiring in Control Panel for Control Bldg Air Conditioning Sys ML20210P3161999-08-0303 August 1999 Discusses Investigation Rept 1-98-005,conducted Between 980129 & 0527 at Seabrook Station & Forwards Nov.Violation Re Discrimination of Williams Power Corp,Contractor of Naesco,Against Electrician for Raising Safety Issues 1999-09-08
[Table view] Category:INCOMING CORRESPONDENCE
MONTHYEARML20217F5841999-10-13013 October 1999 Requests Revocation of License OP-11038-1 for GE Kingsley. Individual Has Been Reassigned to Position within Naesco ML20217F5811999-10-13013 October 1999 Forwards Insp Data & Naesco Evaluation of a EDG Exhaust Insp Conducted on 990407.Insp Ensured That Unacceptable Wall Thinning Will Not Occur During 40-year Design Lifetime of Sys ML20217B8621999-10-0505 October 1999 Forwards Rev 28,change 1 to EPIP Er 1.1, Classification & Emergencies, Per 10CFR50.54(q).Rev to Procedure Does Not Decrease Effectiveness of Seabrook Station Radiological Emergency Plan ML20217B7471999-10-0101 October 1999 Provides Notification of Change in PCT of More than 50 F,Per Requirements of 10CFR50.46(a)(3)(i),(ii).Tabulation of Large Break LOCA PCT Margin Utilization Applicable to Seabrook Station,Encl ML20212G5071999-09-21021 September 1999 Submits Complaint to NRC Re NRC Failure to Cite Seabrook Station NPP Operators for Failing to Periodically Calibrate & Establish Adequate Measures to Insure That Relay Equipment Met All Required Calibration Settings Prior to Installation ML20212B9511999-09-17017 September 1999 Forwards NRC Form 396 for MG Sketchley,License SOP-10685, Along with Supporting Medical Exam Info.Nrc Form 396 Has Been Superceded by Revised Version Dtd 971222,which Was Previously Submitted to NRC on 990812.Encl Withheld ML20212C3621999-09-15015 September 1999 Forwards Rev 34 to Seabrook Station Radiological Emergency Plan & Rev 85 to Seabrook Station Emergency Response Manual, Per 10CFR50,App E & 10CFR50.4 ML20211Q8521999-09-0808 September 1999 Informs That Rl Couture,License SOP-11027,terminated Employment at Naesco on 990907.Revocation of License Requested ML20211N8781999-09-0303 September 1999 Forwards Response to 990820 RFI Re NRC Administrative Ltr 99-03, Preparation & Scheduling of Operator Licensing Exams ML20211J9291999-09-0303 September 1999 Forwards mark-ups & Retypes of Proposed Conforming License Changes Required in Connection with Transfers Being Sought in 990615 Application of Montaup Electric Co & New England Power Co for Transfer of Licenses & Ownership Interests ML20211M3221999-09-0202 September 1999 Responds to NRC Re Violations Noted in Insp of License NPF-86 & Proposed Imposition of Civil Penalty. Corrective Actions:Conducted Prompt Review of Layoff Decision to Determine Relevant Facts ML20211J8411999-09-0101 September 1999 Forwards Updated NRC Form 396 for E Decosta,Nrc License OP-10655-1.Without Encl ML20211J8811999-09-0101 September 1999 Forwards Comments on Seabrook Station Review of Reactor Vessel Integrity Database (Rvid)(Version 2).Minor Discrepancies Were Noted.Proposed Changes Are Encl in Order to Correct Discrepancies ML20211G9191999-08-27027 August 1999 Informs NRC That Name of New Company, Ref in Order Approving Application Re Corporate Merger Is Nstar Which Is Massachusetts Business Trust ML20211G7761999-08-24024 August 1999 Expresses Great Concern Re Lack of Enforcement Actions Against Seabrook Station Despite Citations NRC Has Issued for Violations of Seabrook Operating License ML20211J2171999-08-23023 August 1999 Expresses Disappointment with Lack of Enforcement Action Against Seabrook Station Despite Repeated Safety Violations ML20211J4971999-08-21021 August 1999 Submits Comments Re Violations Cited in Early Mar & 990509 Insps ML20211H8361999-08-19019 August 1999 Submits Concerns Re Violations at Seabrook Station ML20211J3241999-08-15015 August 1999 Expresses Disappointment in Apparent Failure of NRC to Cite Seabrook Station NPP for Recent Violations of Safety Regulations Uncovered During Recent Insps in Mar & May ML20211J1831999-08-15015 August 1999 Submits Concerns Over Serious Deficiencies at Seabrook Station That NRC Has Declined to Take Enforcement Actions Against ML20211J2071999-08-13013 August 1999 Expresses Concerns Re Violations Occurring Recently at Seabrook Nuclear Power Station.Requests Effort to See That Measures Taken to Stop Flagrant,Continuing Violations That Hold Danger to Workers & Community ML20210S2001999-08-12012 August 1999 Forwards NRC Forms 398 & 396 in Support of Applications for Renewal of Operator Licenses for Individuals Listed Below. Without Encls ML20210R8401999-08-11011 August 1999 Forwards Response to NRC Second RAI Re GL 95-07, Pressure Locking & Thermal Binding of SR Power-Operated Gate Valves ML20210R9581999-08-11011 August 1999 Forwards ISI Exam Rept of Seabrook Station, for RFO 6, Period 3,for Insps Conducted Prior to & During Sixth Refueling Outage Concluded on 990510 ML20210R7931999-08-10010 August 1999 Forwards Cycle 7 Startup Rept for Seabrook Station, IAW Requirements of TS 6.8.1.1 ML20210K3281999-07-30030 July 1999 Forwards Response to NRC RAI Re License Amend Request 98-17. North Atlantic Concurs with Staff That Bases Should State That Maintaining ECCS Piping Full of Water from RWST to Reactor Coolant Sys Ensures Sys Will Perform Properly ML20210H8991999-07-27027 July 1999 Forwards Tabulation of Current LBLOCA & SBLOCA Peak Clad Temp Margin Utilization Tables Applicable to Seabrook Station ML20210H0921999-07-27027 July 1999 Forwards Naesc Semi-Annual Fitness-for-Duty Rept,Jan-June 1999, Per 10CFR26.71(d).Rept Includes Data from 990101- 0610 ML20210S9911999-07-18018 July 1999 Requests NRC Intervene for All Shareholders of New England Electric System & to Help with Merger with National Grid Group & That NRC Petition Security & Exchange Commission to Investigate Matter Relative to No Shareholder Options ML20210A2521999-07-15015 July 1999 Forwards Rev 33 to Seabrook Station Radiological Emergency Plan & Rev 84 to Seabrook Station Emergency Response Manual ML20209J0601999-07-14014 July 1999 Forwards Rev 11 to Vols 1-10 of State of Nh Radiological Emergency Response Plan & Vols 11-50 to Town Radiological Emergency Response Plans,In Support of Vermont Yankee & Seabrook Station.Vols 17-19 of Were Not Included ML20209G1351999-07-0909 July 1999 Forwards Relief Request Re Repair Welding on SA-351 Matl to Be Installed in Seabrook Station SW Pumps & SW Cooling Tower Pumps ML20209D2871999-07-0606 July 1999 Submits Response to NRC AL 99-02,re Numerical Estimate of Licensing Actions Expected to Be Submitted in Fy 2000 & 2001.Schedule Does Not Include Activities Which Meet AL Definition of Complex Review ML20209C9021999-06-30030 June 1999 Provides Revised Distribution List for Seabrook Station Correspondence to Reflect Current Organization ML20196G2391999-06-23023 June 1999 Responds to GL 98-01,Suppl 1, Y2K Readiness of Computer Sys at Nuclear Power Plants. Y2K Readiness Disclosure for Plant Encl ML20196G3381999-06-23023 June 1999 Forwards LAR 99-19 for License NPF-86,increasing AOT for Cracs from 30 Days to 60 Days on One Time Basis for Each Train to Facilitate on-line Implementation of Design Enhancements During Current Operating Cycle ML20195J0981999-06-17017 June 1999 Forwards Responses to Questions Posed in Re Application of New England Power Co for Transfer of Control of Licenses NPF-49 & NPF-86.Copy of 1998 Schedule 13G, Included,As Requested ML20196D0561999-06-16016 June 1999 Forwards Certified Copy of Endorsements 77 & 78 to Nelia to Policy NF-0296 ML20195H1741999-06-15015 June 1999 Forwards Original & Copy of Request for Approval of Certain Indirect & Direct Transfer of License & Ownership Interests of Montaup Electric Co (Montaup) with Respect to Nuclear Facilities Described as Listed ML20195J1221999-06-15015 June 1999 Forwards Addl Clarifying Info to Suppl Info Provided at 990602 Predecisional Enforcement Conference at Region I. Proprietary Declarations by Util Employees to Correct Inaccuracies Encl.Proprietary Info Withheld,Per 10CFR2.790 ML20210K4971999-06-15015 June 1999 Forwards Copy of Ltr from Concerned Constitutent AC Menninger from Franconia,Nh to Senator Smith Re Seabrook Nuclear Power Station Y2K Readiness ML20195E9731999-06-0707 June 1999 Forwards Rev 32 to Seabrook Station Radiological Emergency Plan & Rev 83 to Emergency Response Manual ML20206T4201999-05-20020 May 1999 Forwards Certified Copies of Resolution Adopted by Shareholders of National Grid Group Approving Acquisition of New England Electric Sys & Vote of New England Electric Sys Shareholders Approving Merger with National Grid Group ML20196L2001999-05-0707 May 1999 Forwards Rev 01-07-00 to RE-21, Cycle 7 COLR, Per TS 6.8.1.6.c ML20206K4301999-05-0707 May 1999 Forwards Copy of Corrective Order of Notice by State of Nh Nuclear Decommissioning Financing Committee ML20206J3321999-05-0505 May 1999 Forwards Tabulation of Number of Tubes Plugged in Each of Two SGs Inspected During Sixth Isi,Per Plant TS SR 4.4.5.5a. Sixth ISI Was Completed on 990420 ML20206J3341999-05-0505 May 1999 Informs That on 990501,ISO New England & New England Power Pool Implemented Restructured Wholesale Electricity Market. Summary of Util Action as Result of Implementation of Subject Market,Encl ML20206J2801999-04-30030 April 1999 Forwards 1998 Annual Financial Repts for CT Light & Power Co,Western Ma Electric Co,Public Svc Co of Nh,North Atlantic Energy Corp,Northeast Nuclear Energy Co & North Atlantic Energy Svc Corp,License Holders ML20206G4371999-04-30030 April 1999 Forwards 1998 Annual Environ Operating Rept for Seabrook Station.Encl Rept Is Summary of Implementation of EPP for Period of Jan-Dec 1998 ML20206H4801999-04-30030 April 1999 Forwards 1998 Annual Radioactive Effluent Release Rept for Seabrook Station. Listed Info Provided in Encls 1999-09-08
[Table view] Category:RESEARCH INSTITUTION/LABORATORY TO NRC
MONTHYEARML19332G5931989-08-0707 August 1989 Advises That Seabrook Scenario Found Complete & Technically Accurate.No Significant Comments Provided ML20207B6671986-12-0505 December 1986 Forwards Draft Technical Evaluation of Emergency Planning Zone Sensitivity Study for Seabrook ML20207F4651986-11-17017 November 1986 Forwards Amended Pages for NUREG/CR-4540,substituting Pages 43,44 & 60 ML20237L1781986-03-20020 March 1986 Submits Description of Four Dose Assessment Scenarios Generated to Compare Against Licensee Results for Variety of Release Pathways.Licensee Should Be Able to Estimate Source Term & Calculate Offsite Doses for Stated Accident Types ML20211E2261986-02-21021 February 1986 Forwards Review of Seabrook Station Probabilistic Safety Assessment:Containment Failure Modes & Radiological Source Terms. W/O Encl ML20211E1441985-09-13013 September 1985 Forwards Draft BNL Rept, Review of Seabrook Station Probabilistic Safety Assessment:Containment Failure Modes & Radiological Source Terms ML20214F5101985-03-13013 March 1985 Forwards List of Questions Re Plant Pra,Per 850512 Telcon. Statement of Work, Review of PRA for Seabrook Nuclear Power Plant, Encl ML20211D1091985-02-0606 February 1985 Forwards Util Responses to Questions Re Probabilistic Safety Assessment ML20206J2911985-01-31031 January 1985 Forwards Draft Preliminary Review & Evaluation of Seabrook Probabilistic Safety Study. Rept Satisfies Level 1 Review Milestone.W/O Stated Encl.Related Info Encl ML20211D0421985-01-17017 January 1985 Discusses Options for Concluding Review of Facility Probabilistic Safety Assessment Due to Lack of Cooperation by Util ML20211C8411984-10-0202 October 1984 Forwards Draft Summary of Results Presented in Seabrook PRA, for Review & Comment ML20211C4841984-08-13013 August 1984 Forwards Set of Questions on Seabrook Pra,Resulting from Preliminary Work on PRA Review ML20211C4301984-06-22022 June 1984 Discusses Proposal to Review Pra,Examining Aspects of PRA Leading to Estimates of Frequencies of Each Plant Damage State to Determine Accuracy of Estimates ML20065C1471982-08-20020 August 1982 Sumbits Results & Discussion of Both Vehicle Demand Estimates Used as Input Data & Evacuation Time Estimates for Off Season Scenario Using Clear Model ML20003D8311981-03-26026 March 1981 Discusses Results of Limited Analysis for Site.Encl Estimate of Seismic Hazard for Site Developed in Same Manner as Seismic Hazard for Sites Involved in SEP 1989-08-07
[Table view] |
Text
... -- . . . . . - . . . . - -. -. . . . .
,9r h BROOKHAVEN NATIONAL LABORATORY
{ ASSOCIATED UNIVERSITIES. INC.
Upton Long Island. New York 11973 DEC 311986 (516) 282s I Department of Nuclear Energy FTS 666' 2626 Building 130 i
November 17, 1986 Mr. Warren Lyon U.S. Nuclear Regulatory Commission Mail Stop 544 (Phillips Building)
Washington, D.C. 20555 RE: FIN A-3778
Dear Warren:
Enclosed please find the amended pages for the Seabrook report (NUREG/CR-
. 4540), which should be substituted for pages 43, 44 and 60.
Please feel free to call me,1f you have any questions or comments.
Sincerely,
'1 k' Mohsen Khatib-Rahoar, Group Leader Accident Analysis Group MKR/df Enclosures
^
cc: W.T. Pratt R.A. Bari W.Y. Kato I
7'7 0.!G 6 0 R74; 4f f'
~' , . .
concrete interaction for a dry cavity situation. For sequences in which early and intermediate failure is not expected to occur, and' for which containment sprays are inoperable, failure is expected to be a certainty.
The conditional probability for a late overpressurization failure with a vaporization release (dry cavity) is shown to be 0.60 for large break 1.0CAs and-0.89 for small breaks and transients. This results from the relative com-petition between the late overpressure failure and the basemat penetration (TW) for accident sequences without the containment sprays for both low pres-sure (AE) and high pressure (SE, TE) scenarios.
The failure time for the late overpressurization failure mode is mgch longer than previously calcul ated for other large dry containment.l. ."
This is as a result of the very high failure pressure for the Seabrook con-tainment. As a consequence of this high containment failure pressure (median pressure of 211 for wet and 187 psia for dry
- sequences) it is difficult to challenge the containment integrity by any conceivable event.
Hydrogen deflagration early in the accident sequence or later after vessel failure when steam condensation occurring as a result of reactivation o sprays (due to regaining of ac power), or other natural heat sink mechanisms,{
which can produce a deinerted atmosphere is not expected to challenge the con-tainment integrity.
The impact of changes in the containment failure distribution discussed in 3.2.5.4 is not significant for late failures.
Basemat Penetration Failure (S4, TW) can result in the absence of containment
- heat removal system (sprays) for a dry cavity. A 26-inch high curb surrounds the reactor cavity that prevents the entry of water into the cavity unless all of the water from the RWST has been injected. The conditional probability of the basemat melt through is usually less than the late overpressurization failure, this is particularly true for Seabrook where there is a natural bed rock formation directly under the basemat foundation. Therefore, the basemat penetration failure probabilities are conservatively assigned.
No Failure (S5, T!i) would result for all sequences with full spray operation.
The radiological release are thus limited to the design basis leakage with essentially negligible off-site consequences.
Containment Isolation Failure (S6, 3Ti) is represented by an 8-inch diameter l purge line. The accident sequences where the containment is either not isola-ted or bypassed (Event V) are assigned to these release categories. ,
In the SSPSA, the conditional probability for failure to isolate contain-ment (p-failure mode) is assumed to be negligibly small . This is believed to be an optimistic assumption on the part of the applicant, because even for subatmospheric containment the p-failure mode is expected to have a condi-
*For dry sequences, only primary system water inventory is available in the
! containment. In this case, the containment atmosphere becomes superheated and, at failure, the temperature can exceed 700*F.
l l
t
, l tional failure probability ranging from 4x10 " to about 2x10 3; therefore, one expects the conditional p-failure mode probability r a large dry containment to be somewhat higher, and perhaps approaching =10-An interfacing systems LOCA (V sequence) results from valve oisc rupture or disc failing open for series check valves that normally separate the high pressure system. This event results in a LOCA in which the reactor coolant bypasses the containment and results in a loss-of-coolant outside the contain-ment. Furthermore, the concurrent assuned loss of RHR and coolant make-up capability leads to severe core damage. In the SSPSA, only three possible interfacing systems LOCA sequences have been found and discussed. These are:
- 1. Disc rupture of the check valve in the cold-leg injection lines of the RHR.
- 2. Disc rupture of the two series motor-operated valves in the normal RHR hot-leg suction.
- 3. Disc rupture of the motor-operated valve equipped with a stem mounted
~ ~
limit switch and " disc failing open while indicated closed" in the other motor-operated valve in the normal RHR hot-leg suction.
For the V-sequence, the core melts early with a low RCS pressure and a dry reactor cavity at vessel melt-through. The containment sump remains dry and recirculation is not possible.
The core and containment phenomenology used to arrive at the split frac-tions for the containment event tree and thug "the C-matrix are in general i
agreement with the other previous studies , ,- for PWRs with large dry containments. Furthermore, the' claimed unusually high strength of the Sea-brook containment reduces the impact of sensitivity caused by uncertainties in the severe accident progression. However, should the claimed strength of the containment be reduced to levels comparable to some of the other large dry containments, the impact of uncertainties may becpe significantly more pro-nounced, as discussed on our review of the MPSS-3.
3.6 Release Category Frequencies Based on the containment class frequencies in Table 3.6 and the contain-ment failure matrix of Table 3.9, the release frequencies were computed and are summarized in Table 3.10. Table 3.10 indicates that only eight of the release categories dominate the total release frequency.
Tables 3.11 and 3.12 set forth the contribution to core melt frequency from the various containment response classes and release categories, respec-tively. It is seen that containment classes 2, 4, and 5 dominate the co're melt frequency while the release categories S5 (containment intact), 3T and S3V dominate the source term frequency.
c- ,,w=-.-,.,aw,-,--- -*- e -w-- %--,y . + - - - - - - - - - -+--+--e-. - - - - - - ---,-r---- ---------w-y,w - m - -
r-- -=g-w we
, N ,a ~ .
i
- 5.
SUMMARY
AND CONCLUSIONS ,
i The purpose of this report is tc describ'e the technical review of the Sea-brook Station Probabilistic Safety Assessment and to present an assessment of containment performance, and radiological source term estimates for severe core melt accidents.
The containment response to severe accidents is judged to be an important factor in mitigating the severe accident risk.- There is negligible probability of prompt containment failure. Failure during the first few hours of overpressure failure is
'after corecompared very long melt is also unlikely to the and Reactor the timing Safety Study (WASH-1400).Most core melt accidents would be effectively mitigated by containment spray operation. A comparison of SSPSA and RSS containment failure frequencies is given in Table 5.1.
~
Our assessment of the containment failure characteristics indicate that, there is indeed a tendency to fail containment through a realistic benign mode compared with the traditional gross failures.
The . point-estimate release fractions used in the SSPSA are comparable in magnitude to those used in the RSS. In those cases where comparisons can be made to the more mechanistic source term study carried out by the Accident Source Term Program Office ( ASTP0) of the NRC and reported in BMI-2104 it was found that.the SSPSA releases were either higher than or for the most part similar to the recent release fractions. It was also found that the energy of release was somewhat higher in the SSPSA than for other existing studies.
l r
l i
.-}}