Letter Sequence RAI |
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MONTHYEARML20247F3961998-05-13013 May 1998 Forwards RAI Re 980306 Submittal Which Transmitted Paducah Gaseous Diffusion Plant Seismic Hazard Analysis.Addl Info Should Be Provided within 21 Days of This Ltr Project stage: RAI ML20249B9211998-06-18018 June 1998 Informs That Licensee Identified Addl Problems W/Analysis Documentation Associated W/Updated Seismic Hazard Analysis Performed by Risk Engineering,Inc,Submitted on 971201 & Revised 980306 Project stage: Other ML20151Y1411998-09-11011 September 1998 Informs NRC of Change in Completion Date for Two Regulatory Commitments Re Updated Seismic Hazard Analysis,Per Licensee .Commitments Made in Ltr,Provided in Encl Project stage: Other ML20153D3641998-09-18018 September 1998 Forwards Rev 2 to Final Rept Updated Probabilistic Seismic Hazard Analyses for Paducah Gaseous Diffusion Plant Paducah, Ky, for NRC Approval.Deviations from Procedural Requirements Identified & Corrective Actions Implemented Project stage: Other ML20154P7881998-10-21021 October 1998 Forwards RAI Re Usec 980306 Transmittal of Paducah Gaseous Diffusion Plant Seismic Hazard Analysis.Requested Addl Info Should Be Provided within 21 Days of Ltr Project stage: RAI ML20195D5481998-11-10010 November 1998 Forwards Response to NRC 981021 RAI Re Licensee Updated Probabilistic Seismic Hazard Analysis Final Rept,Transmitted in .Technical Rept NCEER-97-0010,encl Project stage: Other ML20207J7641999-03-11011 March 1999 Requests Addl Info,Specified in Encl,Re 980918 Paducah Gaseous Diffusion Plant Seismic Hazard Analysis,Rev 2,for Staff Review Project stage: Approval ML20206K0061999-05-0404 May 1999 Forwards Rev 3 to Updated Probabilistic Seismic Hazard Analysis for Paducah Gaseous Diffusion Plant,Paducah,Ky, for NRC Approval.Without Encl Project stage: Other 1998-06-18
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Category:CORRESPONDENCE-LETTERS
MONTHYEARML20217N7591999-10-18018 October 1999 Provides Monthly Update on Progress of Installation of Seismic Upgrade Mods to Bldgs C-331 & C-335 ML20217M3861999-10-15015 October 1999 Provides Addl Changes to SAR Update Certificate Amend Request,Containing Changes That Resulted from re-evaluation of Autoclave head-to-shell O-ring Leakage Analysis Provided by DOE SAR Repts ML20217G1731999-10-14014 October 1999 Requests Addl Info Re Applications Dtd 990924,requesting Amends to Cocs for Paducah & Portsmouth GDPs for Revised QA Programs.Encl Identifies Specific Info Needed.Info Should Be Provided within 30 Days ML20217G1811999-10-14014 October 1999 Forwards Reissued Amend to Coc for Usec Paducah Gdp.Coc Corrects Coc Issued on 991006.Amend Number & Effective Date Were Inadvertently Incorporated as 3 & 991026,instead of 4 & 991105 ML20217F6801999-10-12012 October 1999 Forwards Updated Paducah GDP Certificate Amend Requests at NRC for Approval ML20217B2801999-10-0606 October 1999 Forwards Insp Rept 70-7001/99-203 on 990921-23.No Violations Noted ML20217B3521999-10-0606 October 1999 Forwards Amend 3 to Certificate of Compliance GDP-1 to Revise Six Technical Safety Requirements Sections.Sections Are 2.1.4.17,2.1.4.8,2.3.4.1,2.3.4.4,2.3.4.16 & 3.10.4.b. Compliance Evaluation Rept Also Encl ML20212K8941999-10-0404 October 1999 Forwards Insp Rept 70-7001/99-10 on 990720-0907 & Forwards NOV Indicating That Some Personnel Were Incorrectly Granted Unescorted Access to Controlled Access Areas Without Having Necessary Specific Training ML20216J8931999-10-0101 October 1999 Forwards Copy of Security Incident Log & Associated Info for Sept 1999 ML20216J9081999-09-30030 September 1999 Forwards Revised Written Event Rept 99-10,rev 3,pertaining to Corroded Fire Sprinkler Heads Affecting Operability of high-pressure Fire Water (HPFW) Sprinkler Sys.No Commitment Contained in Rept ML20217M3701999-09-29029 September 1999 Submits bi-monthly Update on Progress of Mods to Upgrade Audibility of Criticality Accident Alarm Sys (Caas).Schedule for CAAS Audibility Upgrades Attached ML20212H1251999-09-24024 September 1999 Notifies NRC of Change in Regulatory Commitments Associated with Submittal Date for Update of Application SAR Chapter 3.Specifics of Commitment Changes of Listed ML20212H3801999-09-24024 September 1999 Responds to 990723 RAI Re 1999 Annual Update to Certification Applications ML20212F0981999-09-22022 September 1999 Forwards Insp Rept 70-7001/99-12 on 990830-0902.Purpose of Insp Was to Determine If Security Requirements Adequately Implemented & Included Review of Approved Plant Security Plan.No Violations Identified ML20212H3721999-09-22022 September 1999 Forwards NRC Form 790 Classification Record Documents for Paducah & Portsmouth GDPs That Were Generated During Month of Aug 1999.Without Encl ML20217J1211999-09-20020 September 1999 Submits Listed Comments on NRC Proposed Rule, Reporting Requirements for Nuclear Power Reactors ML20212D4291999-09-17017 September 1999 Forwards Required 30-day Written Event Rept Re Criticality Accident Alarm Sys Response Time in Bldg C-710.Encl 2 Contains Commitments Contained in Submittal ML20212D4231999-09-16016 September 1999 Informs That Review of Event Rept Er 99-12 Revealed Listed Two Statements Inadvertently Omitted from Document ML20212B6611999-09-15015 September 1999 Forwards Insp Rept 70-7001/99-202 on 990816-20.No Violations Noted ML20212D2361999-09-15015 September 1999 Submits Monthly Update on Progress of Installation of Seismic Upgrade Mods to Bldgs C-331 & C-335 ML20212A5531999-09-14014 September 1999 Ack Receipt of Informing NRC of Steps Taken to Correct Violations Noted in Insp Rept 70-7001/99-08 ML20212A5441999-09-14014 September 1999 Ack Receipt of Informing NRC of Steps Taken to Correct Violations Noted in Insp Rept 70-7001/99-07 ML20211Q9951999-09-10010 September 1999 Forwards 30-day Written Rept ER-99-12,re Loss of Power to Autoclave Position 1 North & 1 South Process Gas Leak Detection (Pgld) in Bldg C-333-A.Caused by Electrical Short Circuit.Submitted Work Request 501636 for PI SEX-4 ML20211P2091999-09-0909 September 1999 Provides Staff Written Clarification of NRC Reporting Expectations of When Double Contingency Losses Should Be Reported to NRC IAW Bulletin 91-001, Reporting Loss of Criticality Safety Controls, & Suppl ML20216E4891999-09-0909 September 1999 Responds to Violations Noted in Insp Rept 70-7001/99-08. Corrective Actions:On 990602 Responsible Organization Manager Met with FP Engineer Performing Bldg Reappraisal & Made Clear Expectation for Prompt Reporting of Deficiencies ML20211P3831999-09-0303 September 1999 Forwards Coc GDP-1,amend 3 & Coc GDP-2,amend 4 for Paducah (Pgdp) & Portsmouth (Ports) Gdps,Respectively by Revising Pgdp & Ports QAPs in Vol 3 of Respective Certificate Applications ML20211L6441999-09-0202 September 1999 Forwards Insp Rept 70-7001/99-11 on 990802-06.No Violations Noted.Insp Consisted of Selective Exam of Procedures & Representative Records,Interviews with Personnel & Observations of Activities in Progress ML20211M3551999-09-0101 September 1999 Forwards Copy of Security Incident Log & Associated Info for Month of Aug 1999,IAW 10CFR95.57(b) ML20211K4041999-08-31031 August 1999 Forwards Responses to Remaining NRC Questions/Comments from 980601 & 0709 NRC RAIs Re SAR Update ML20211M7031999-08-30030 August 1999 Forwards Proprietary Rev 0 to Arming & Arrest Authority Security Plan for Paducah & Portsmouth Gaseous Diffusion Plants, for Review & Approval.Encl Withheld ML20211G9971999-08-26026 August 1999 Forwards Rev 2 to Written Rept Er 99-10,re Corroded Fire Sprinkler Sys in Bldg C-337 & C-333.Analysis of Root Cause Has Not Been Completed.Statistically Based Sprinkler head- Sampling Plan Has Been Completed & Approved ML20211D9751999-08-20020 August 1999 Forwards Rev 1 to Final Written Event Rept Er 99-11,re Unplanned Actuation of C-333-A Autoclave 1 North Autoclave Steam Pressure Control Sys (Aspcs) on 990623 ML20211F1761999-08-20020 August 1999 Requests That Paducah GDP facility,C-709 Lab Annex Bldg Be Added to List of Facilities to Be Exempted from CAAS Detection Coverage ML20211B5021999-08-20020 August 1999 Forwards Amend 2 to Certificate of Compliances GDP-1, Revising Paducah GDP Technical Safety Requirements Re Audibility Requirements for Criticality Accident Alarm Sys at Facility & Related Sections of SAR ML20211A7011999-08-17017 August 1999 Forwards Copy of Final Amend to 10CFR76 for Info of Subcommittee.Final Rule Is Being Transmitted to Fr for Publication.Final Rule Will Amend Regulations That Apply to Paducah & Portsmouth Gaseous Diffusion Plants ML20211D5811999-08-16016 August 1999 Submits Monthly Update on Progress of Installation of Seismic Upgrade Mods to Bldgs C-331 & C-335 ML20210P7421999-08-10010 August 1999 Forwards Insp Rept 70-7001/99-08 on 990529-0719 & Nov. Violations of Concern Because Late Reporting of Problems with safety-related Equipment Could Negatively Impact Continued Availability of Equipment ML20210Q6061999-08-0909 August 1999 Forwards NRC Form 790 Classification Record Documents for Paducah & Portsmouth Gdps,Per 10CFR95.57.Records Were Generated During Month of July 1999.Without Encl ML20210L6571999-08-0404 August 1999 Informs That Staff Completed Initial Review of 990720 Application to Amend Coc GDP-1.Staff Anticipates Completing Review by 990930 ML20211A7901999-08-0404 August 1999 Forwards Info Requested During Briefing by NRC Staff on 990726 Re NRC Interactions with Usec ML20210J1331999-07-30030 July 1999 Forwards Copy of Security Incident Log & Associated Info for Month of July 1999,per Reporting Requirements of 10CFR95.57(b) ML20210H3161999-07-30030 July 1999 Forwards Rev 1 to Written Event Rept ER-99-10,re Corroded Fire Sprinkler Heads Affecting Operability of HP Fire Water Sprinkler Sys in Bldg C-337 & C-333.Testing & Analysis of Root Cause & Corrective Actions Necessary Are Not Complete ML20210P7871999-07-29029 July 1999 Provides bi-monthly Update on Progress of Modifications to Upgrade Audibility of Criticality Accident Alarm Sys,In Response to NRC 981217 Request 1999-09-09
[Table view] Category:OUTGOING CORRESPONDENCE
MONTHYEARML20217G1731999-10-14014 October 1999 Requests Addl Info Re Applications Dtd 990924,requesting Amends to Cocs for Paducah & Portsmouth GDPs for Revised QA Programs.Encl Identifies Specific Info Needed.Info Should Be Provided within 30 Days ML20217G1811999-10-14014 October 1999 Forwards Reissued Amend to Coc for Usec Paducah Gdp.Coc Corrects Coc Issued on 991006.Amend Number & Effective Date Were Inadvertently Incorporated as 3 & 991026,instead of 4 & 991105 ML20217B2801999-10-0606 October 1999 Forwards Insp Rept 70-7001/99-203 on 990921-23.No Violations Noted ML20217B3521999-10-0606 October 1999 Forwards Amend 3 to Certificate of Compliance GDP-1 to Revise Six Technical Safety Requirements Sections.Sections Are 2.1.4.17,2.1.4.8,2.3.4.1,2.3.4.4,2.3.4.16 & 3.10.4.b. Compliance Evaluation Rept Also Encl ML20212K8941999-10-0404 October 1999 Forwards Insp Rept 70-7001/99-10 on 990720-0907 & Forwards NOV Indicating That Some Personnel Were Incorrectly Granted Unescorted Access to Controlled Access Areas Without Having Necessary Specific Training ML20212F0981999-09-22022 September 1999 Forwards Insp Rept 70-7001/99-12 on 990830-0902.Purpose of Insp Was to Determine If Security Requirements Adequately Implemented & Included Review of Approved Plant Security Plan.No Violations Identified ML20212B6611999-09-15015 September 1999 Forwards Insp Rept 70-7001/99-202 on 990816-20.No Violations Noted ML20212A5441999-09-14014 September 1999 Ack Receipt of Informing NRC of Steps Taken to Correct Violations Noted in Insp Rept 70-7001/99-07 ML20212A5531999-09-14014 September 1999 Ack Receipt of Informing NRC of Steps Taken to Correct Violations Noted in Insp Rept 70-7001/99-08 ML20211P2091999-09-0909 September 1999 Provides Staff Written Clarification of NRC Reporting Expectations of When Double Contingency Losses Should Be Reported to NRC IAW Bulletin 91-001, Reporting Loss of Criticality Safety Controls, & Suppl ML20211P3831999-09-0303 September 1999 Forwards Coc GDP-1,amend 3 & Coc GDP-2,amend 4 for Paducah (Pgdp) & Portsmouth (Ports) Gdps,Respectively by Revising Pgdp & Ports QAPs in Vol 3 of Respective Certificate Applications ML20211L6441999-09-0202 September 1999 Forwards Insp Rept 70-7001/99-11 on 990802-06.No Violations Noted.Insp Consisted of Selective Exam of Procedures & Representative Records,Interviews with Personnel & Observations of Activities in Progress ML20211B5021999-08-20020 August 1999 Forwards Amend 2 to Certificate of Compliances GDP-1, Revising Paducah GDP Technical Safety Requirements Re Audibility Requirements for Criticality Accident Alarm Sys at Facility & Related Sections of SAR ML20211A7011999-08-17017 August 1999 Forwards Copy of Final Amend to 10CFR76 for Info of Subcommittee.Final Rule Is Being Transmitted to Fr for Publication.Final Rule Will Amend Regulations That Apply to Paducah & Portsmouth Gaseous Diffusion Plants ML20210P7421999-08-10010 August 1999 Forwards Insp Rept 70-7001/99-08 on 990529-0719 & Nov. Violations of Concern Because Late Reporting of Problems with safety-related Equipment Could Negatively Impact Continued Availability of Equipment ML20210L6571999-08-0404 August 1999 Informs That Staff Completed Initial Review of 990720 Application to Amend Coc GDP-1.Staff Anticipates Completing Review by 990930 ML20211A7901999-08-0404 August 1999 Forwards Info Requested During Briefing by NRC Staff on 990726 Re NRC Interactions with Usec ML20210F9761999-07-28028 July 1999 Forwards Compliance Evaluation Rept Prepared to Support Amend of Coc GDP-1 Re Criticality Accident Alarm Sys Audibility.Notice of Amend Forwarded to Ofc of Fr Also Encl ML20210G0391999-07-26026 July 1999 Forwards Compliance Evaluation Rept & Fr Notice for Revised Qaps,Per 990212 Application ML20210D8181999-07-23023 July 1999 Submits Response to SA Toelle Ltr Dtd 990614, 10CFR76.68(a)(3) Decreased Effectiveness Reviews & RAI for Paducah & Portsmouth Transmittals of 1999 Annual Update to Certification Applications ML20210V3481999-07-16016 July 1999 Informs That Staff Completed Review of New Payment Surety Bonds (Psb) for Paducah & Portsmouth Gdps,Which Were Provided in .Cancelled Psbs for Liberty Mutual Insurance Co & Safeco Insurance Co of America,Encl ML20209F0611999-07-0909 July 1999 Forwards Insp Rept 70-7001/99-09 on 990621-25.No Violations Noted ML20196K0981999-07-0101 July 1999 Forwards Insp Rept 70-7001/99-07 on 990413-0528 & Nov. Violations Re Failure to Fully Evaluate Situation in Which Safety Sys Relied Upon to Mitigate Consequences of Accident Was Inappropriately Returned to Svc ML20196A1571999-06-17017 June 1999 Confirms Discussions Between K O'Brien & L Jackson to Conduct Meeting on 990630 to Discuss Apparent Violation ML20207F1311999-06-0404 June 1999 Responds to Requesting Copy of OI Rept 3-1998-033 Re Docket Potential Violation of 10CFR76.7 Concerning Employee Protection at Plant.Request Denied for Listed Reasons ML20207F2571999-06-0202 June 1999 Informs That NRC Disagrees with Usec Conclusion for Not re-opening Issue 2 of Compliance Plan,Since Proposed Change to Sarup Submittal Constitutes Major Rev to Operating Safety Bases Contained in Technical Safety Requirements ML20207E8201999-05-18018 May 1999 Refers to Investigation Case 3-1998-033 Re Apparent Violation Involving Usec & Lockheed-Martin Utility Service, Inc Mgt Discriminating Against Employee at Paducah Gaseous Diffusion Plant.Synopsis Encl.Without Encl 2 ML20206N3851999-05-12012 May 1999 Forwards Amend 1 to Coc GDP-1 & Amend 3 to Coc GDP-2 IAW 990316 Applications,Revising Paducah & Portsmouth Gaseous Diffusion Plants Technical Safety Requirement Sections 3.1.1 & 3.10.4 ML20206H5161999-05-0606 May 1999 Informs That NRC Will Not Be Able to Complete Review of Paducah Certificate Amend Request on Criticality Accident Alarm Sys Audibility Upgrade by 990507,as Indicated in NRC .Review Should Be Completed by 990630 ML20206E6481999-04-29029 April 1999 Forwards Insp Rept 70-7001/99-04 on 990224-0412.No Violations Noted ML20205R8041999-04-20020 April 1999 Forwards Partially Withheld Insp Rept 70-7001/99-201 Conducted on 990322-26.Scope & Results of Insp Summarized in Rept ML20205K4251999-04-0707 April 1999 Forwards Compliance Evaluation Rept for GDP-1 & GDP-2, Supporting Change in Title of Executive Vice President, Operations.Notice of Amend,Which Has Been Forwarded to Ofc of Fr for Publication,Encl ML20205K4481999-04-0707 April 1999 Forwards Addl Info Needed for Staff to Complete Review of 990112 Application for Amend Re Seismic Upgrades for Bldgs C-331 & C-335 at Paducah Gaseous Diffusion Plant ML20205J3021999-04-0202 April 1999 Forwards Insp Rept 70-7001/99-05 on 990322-25.No Violations Noted.Insp Included Review of Approved Paducah Physical Security Plan ML20204H9611999-03-18018 March 1999 Forwards RAI Re 990212 Applications Requesting Amends to Coc for Paducah & Portsmouth Gaseous Diffusion Plants for Revised QAPs ML20204C2721999-03-17017 March 1999 Ack Receipt of Application to Amend Coc GDP-1,re Criticality Sys Audibility Upgrades,Transmitted by Ltr . NMSS Anticipates Completing Technical Review by 990301 ML20204F2511999-03-17017 March 1999 Ack Receipt of Informing NRC of Steps Taken to Correct Violations Noted in Insp Rept 70-7001/98-18.Actions Will Be Examined During Future Insp ML20207M1081999-03-11011 March 1999 Discusses Us Enrichment Corp Participation in Round Robin Sample Exchange Program Administered by Nbl for Verfying Quality of Licensee U Destructive Measurement Sys.Invoices FL0237-99 & FL0238-99 for Amount Listed Encl ML20207K3011999-03-11011 March 1999 Forwards Insp Rept 70-7001/99-01 on 990113-0223.No Violation Noted.Continuing Problems with Some Plant Staff Understanding & Adherence to long-standing Plant Policies & Procedures Were Found ML20207J7641999-03-11011 March 1999 Requests Addl Info,Specified in Encl,Re 980918 Paducah Gaseous Diffusion Plant Seismic Hazard Analysis,Rev 2,for Staff Review ML20207G2231999-03-0505 March 1999 Discusses Insp Rept 70-7001/98-18 on 981201-990112 & Forwards Notice of Violation Re Failure to Maintain Control of Classified Matter at Paducah Facility ML20207B3361999-03-0202 March 1999 Ack Receipt of 990212 Applications for Amend to Cocs GDP-1 & GDP-2.Staff Has Completed Initial Administrative Rev of Applications & No Omissions of Deficiencies Were Identified. Staff Anticipates Completing Review by 990416 ML20203G4011999-02-0909 February 1999 Forwards Insp Rept 70-7001/99-02 on 990125-29.No Violations Noted.Insp Consisted of Selective Exam of Procedures & Representative Records,Interviews with Personnel & Observations of Activities in Progress ML20202G2501999-01-29029 January 1999 Discusses 990125 Meeting with Us Enrichment Corp in Lisle,Il Re Implementation Status of C/A Plans for Nuclear Criticality Safety Program & Basis for Proposed Changes to Completion Dates for Some C/A.List of Attendees Encl ML20202F0531999-01-29029 January 1999 Forwards Renewed Cocs for Paducah & Portsmouth Gaseous Diffusion Plants Located in Paducah,Ky & Piketon,Oh. Compliance Evaluation Rept Encl Also ML20202F5731999-01-26026 January 1999 Informs That Chairman Has Sent Rept to Congress on Gaseous Diffusion Plants,As Required by Aec.Rept Discusses Status of Health,Safety & Environ Conditions at Plants Located Near Paducah,Ky & Portsmouth,Oh for Period from 971001-980930 ML20202F0461999-01-26026 January 1999 Expresses Appreciation for 981104,comments on Draft Rept to Congress.Changes Were Made to Rept to Address All of Comments Except for One.Event Notification Summary Was Not Revised to Addl Info Requested ML20202F5591999-01-26026 January 1999 Expresses Appreciation for 981104,comments on Draft Rept to Congress.Future Repts Will Be Prepared in Conjunction with Recertification Reviews ML20199H1011999-01-15015 January 1999 Forwards Second NRC Rept to Congress,Covering Period from 971001-980930.Rept Discusses Status of Health,Safety & Environ Conditions at Gaseous Diffusion Plants Near Paducah,Ky & Portsmouth,Oh ML20199G2161999-01-14014 January 1999 Forwards Amend 23 to Coc GDP-1,revising TS Requirement 2.3.4.7 on Product & Tails Withdrawal Facilities Criticality Accident Alarm Sys 1999-09-09
[Table view] |
Text
- __ _-____ - _ _ ___ - __ _ _ _ ______ _
Mayu13, 1998 i
Mr. Steve A. Toelle, Manager Nuclear Regulatory Assurance and Policy U.S. Enrichment Corporation 2 Democracy Center 6903 Rockledge Drive Bethesda, MD 20817-1818
SUBJECT:
PADUCAH GASEOUS DIFFUSION PLANT SEISMIC HAZARD ANALYSIS (TAC NO. L32054)
Dear Mr. Toelle:
This refers to your submittal dated March 6,1998, which transmitted the Paducah Gaseous Diffusion Plant Seismic Hazard Analysis for staff review.
Our review of your submittal has identified additional information that is needed for the staff to complete its review. The additional information, specified in the enclosure, should be provided within 21 days of this letter. Please reference the above TAC No. in future correspondence related to this review.
If you have any questions conceming this request, please contact me or Andrew Persinko, of my staff, at (301) 415-6522.
Sincerely, M @ fd S19fl8d %
Robert C. Pierson, Chief Special Projects Branch Division of Fuel Cycle Safety and Safeguards Office of Nuclear Material Safety and Safeguards
Enclosure:
As stated (
cc: Mr. Steve Polston, PGDP )
Docket 70-7001 sTRIBuTioN:hM Docket 70-7001 INRC File Center & PUBLIC NMss r/f FCs3 r/f sPB r/f Rlil PHiland. Riti - Ko"Brien, Riti oFC NB h sPB k {s h sPB b SPJA NAME Persinko:lj diey n h erson DATE h8 Y eg(98 96 [M8 i M48
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!' Request for AdditionalInformation l Submittal Dated March 6,1998 United States Enrichment Corporation Paducah Gaseous Diffusion Plant Docket No. 70 7001 l Please provide the following information:
l
- 1. Assumption of temporal clustering Regarding the discussion of single and clustered events (pages 2-3 to 2-6), the report asserts that an assumption of clustering is more conservative for the large events.
- a) Are you assuming that the recurrence of an event can be used in place of the probability of exceeding that event (page 2-3)?
b) In the example, it appears that you use the same recurrence for the three j independent events as for one clustered event to arrive at the probability of exceeding the values of 0.03 and 0.01, respectively. Is that correct or does this analysis assume that the recurrence of a clustered event is exactly 1/3 the l- recurrence of the independent events? Is there any technicaljustification to support this assumption, i.e., could clustered events occur more frequently than the combination of single events?
l c) Because the return period of interest is 250 years, do the large, but infrequent l earthquakes, really control the peak ground motion? Otherwise the assumption of independent events would, according to the calculations, increase the hazard.
d) The effect of the assumption of temporal clustering for large earthquakes occurring in the NMSZ on the recurrence rate of small to moderate earthquakes should be further discussed. It would be helpful to have a figure comparing l magnitude-recurrence curves with and without the assumption of temporal clustering for the NMSZ source. Especially, how would this assumption affect the return period (or the recurrence rate) of a 0.15g earthquake?
- 2. Logic tree for rates of large event on East Prairie fault and East Prairie extension What is the sensitivity of the weighting given to the weighting of the logic tree on pages 3-14 and 3-15; especially rate of large earthquake, recurrence, and length of East Prairie Extension (because the curve, figure c-1 for example, goes all the way to 100,000 yrs, the effect on the 250 year earthquake is hard to discern)? Van Arsdale and Johnston conclude that assuming greater weight is not valid because of strain accumulation rates.
Would Van Arsdale and Johnston change their weighting given the most recent GPS f data (Weber et al.,1998)?
- 3. B Values Explain why the b value for the rift is "more stable" than for individual faults. How does application of the system b value compare to the analyses by Hoffman (1996). Have you ;
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2 tested the sensitivity of this assumption? Have you considered reconstruction of magnitude-recurrence relationships from the historical record, in which the data were divided into several sub-populations instead cf a single population (see e.g., Speidel, 1998)?
- 4. Fault Geometry in NMSZ The common assumption is that faults in the NMSZ are reactivated features of a Phanerozoic rift system. Characteristics of faults (e.g., orientation) rely on this assumption. However, Schweig and Ellis (1994) point out that the faults in the NMSZ are young and slightly oblique to the assumed fault traces. Have you done any analyses to test for the sensitivit'/ of small changes in fault orientation? Have you, in any preliminary work treated the zone as a background source, and if so how does that change the 250 year PGA?
- 5. Ground motion attenuation for rock Provide the rationales for varying C1 and C2 (instead of other parameters) to obtain attemative sets of ground motion equations. Using a couple of plots to compare peak and spectral ground motion predictions from the four attemative models used in the Paducah PSHA with those from other attenuation equations in the CEUS., including Atkinson and Boore (1997). According to Abrahamson and Shedlock (1997), Toro et al (1997) predicted lower PGA for smaller earthquakes at all distances and for larger earthquakes at distances greater than about 20 km. Contributions to the PGA at the Paducah site for the 250 year return period are mainly from small and moderate earthquakes (50%), we may not be able to say that the current model is more conservative.
Please provide aerivation of equations 4-3 through 4-5 and rationales for selecting these equations in considering saturation effect. Are parameters a and b the same as those in exponential recurrence model?
- 6. Ground motion attenuation for soil and vertical component a) Provide the actual equations used to calculate the site-specific soil amplification factors as functions of frequency, how these equations were derived, and the selection of data range for the associated parameters. These equations are not transparent in the cited literature. Dynamic material properties, besides shear wave velocity, that were involved in the calculation and selection of data range for these parameters are not discussed or presented in the subject report.
1 b) Also, provide the equations and processes in deriving such equations for calculating the ratio of vertical to horizo. ital ground motion. Again, the equations are not transparent in the cited literature. Please clarify that the vertical motion is calculated from horizontal motion on rock, not on soil.
)
__ __- . _ _ _ _ __ - _ ._ ---_____________-__--____-_-_________A
e 3
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- 7. Hazard Reeults a) Provide the uniform hazard spectra for the 0.15g (i.e., return period of 220 year) event. This would provide a more complete picture of the hazard associated with the 0.15g acceleration used in the analyses, b) Provide a version of hazard curves (figs 5-1 through 5-8,5-11,5-12, and other similar figures in appendix C) that emphasize the range of interests (i.e., near return period of 250 years. For example, cut off the plot at annual P of 1E-03 or SE-03).
- 8. Spectra for Other Damping Ratios Provide the derivation of equations 5-1 and 5-2.
- 9. Other Verify that the Quality Assurance Plan used during the performance of the seismic hazard analysis was the USEC Ouality Assurance Plan. Discuss how the Plan was implemented.
J References Abrahamson, N.A. and W.J. Shedlock.1997. Overview. Seismological / Research Letters I
68(1):9-23.
Atkinson, G.M. and D.M. Boore.1997. Some comparisons between recent ground motion relations. Seismological Research Letters 68(1): 24-40.
l Hoffman, R.B.1996. Individual faults can't produce a Guttenberg-Richter earthquake recurrence. Engineering Geology 43: 5-9. l l
Schweig and Ellis.1994. Reconciling short recurrence intervals with minor deformation in the New Madrid seismic zone. Science 264: 1308-1311.
Speidel.1998. Seismicity relationships in the Central Mississippi Valley. Final Report to U.S.
Army Corp of Engineers /CRGL.
Toro, G.R., N.A. Abrahamson, and J.F. Schneider.1997. Model of strong ground motions from earthquakes in central and eastern north America: best estimates and uncertainties.
Seismological Research Letters 68(1).
Weber et al.,1998. Estimation ofinterplate strain accumulation in the New Madrid seismic zone from repeat GPS surveys. Tectonics 17:250-266.
l l
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