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Category:CORRESPONDENCE-LETTERS
MONTHYEARML20217K1051999-10-19019 October 1999 Ack Receipt of Ltr Dtd 990707,which Transmitted Rev 29 to Callaway Plant Physical Security Plan,Under Provisions of 10CFR50.54(p).Based on Determination That Changes Do Not Decrease Effectiveness of Plan,No NRC Approval Required ML20217G2071999-10-14014 October 1999 Forwards Insp Rept 50-483/99-10 on 990913-16.No Violations Noted.Insp Was to Review Emergency Plan & Procedures During Biennial Emergency Preparedness Exercise ML20217B5901999-10-0505 October 1999 Informs That Staff Concludes That Licensee Responses to GL 97-06 Provides Reasonable Assurance That Condition of Util SG Internals in Compliance with Current Licensing Bases for Callaway Plant,Unit 1 ML20217B5711999-10-0505 October 1999 Discusses GL 98-01 Issued by NRC on 980511 & Uec Responses for Callaway NPP Unit 1 ,990224 & 990628.Informs That Staff Reviewed Responses & Concluded That All Requested Info for GL 98-01 Provided ML20212G0221999-09-22022 September 1999 Forwards Insp Rept 50-483/99-11 on 990812-20.No Violations Noted.Team Found,Weakness in flow-accelerated Corrosion Monitoring Program Resulted in No Previous Insp of Pipe Segment Which Failed ML20212D9341999-09-16016 September 1999 Informs That on 990818,NRC Completed Midcycle PPR of Callaway Plant.In Area of Ep,C/As Taken in Response to Problems Identified During Previous Exercises Warrant More in-dept Review.Details of Insp Plan Through March 2000 Encl ML20217D5791999-09-15015 September 1999 Provides Formal Documentation of Reviews & Discussions Re Technical Ltr Rept for Proprietary Info.Review of Ltr Was Discussed in Telcon & Via e-mail Messages. Summary of Telcons as Documented on 990708,included ML20212A4921999-09-13013 September 1999 Forwards Insp Rept 50-483/99-08 on 990725-0904.Two Severity Level IV Violations of NRC Requirements Identified & Being Treated as Noncited Violations Consistent with App C of Enforcement Policy ML20212A4701999-09-10010 September 1999 Rssponds to NRC 990709 RAI Re Util Relief Request to Allow Use of 1998 Edition of ASME Section Xi,Subsection Iwe. Acceptance Criteria for Liner Plate Pressure Boundary Thickness Will Be Limited to 10% Nominal Thinning ML20212B1521999-09-10010 September 1999 Forwards Insp Rept 50-483/99-07 on 990809-13.No Violations Noted.Inspectors Used Annual Licensed Operator Requalification Exams to Assess Licensed Operator Performance ML20211N0321999-09-0202 September 1999 Forwards SE Concluding That Util Adequately Addressed Actions Requested in GL 95-07, Pressure Locking & Thermal Binding of Safety-Related Power-Operated Gate Valves ML20211B0241999-08-18018 August 1999 Ack Receipt of Ltr Dtd 990714,transmitting Scenario for Licensee Upcoming Biennial Exercise.Based on Review,Nrc Determined That Exercise Scenario Sufficient to Meet Emergency Plan Requirements & Exercise Objectives ML20210T9121999-08-13013 August 1999 Forwards Insp Rept 50-483/99-06 on 990613-0724.One Severity Level 4 Violation Occurred & Being Treated as Ncv,Consistent with App C of Enforcement Policy ML20210R7241999-08-12012 August 1999 Forwards semi-annual Fitness for Duty Program Performance Data Rept for Callaway Nuclear Plant for 990101-990630,IAW 10CFR26.71(d) ML20211A9501999-08-12012 August 1999 Discusses 990720-21 Workshop Conducted in Region IV Ofc,Re Exchange of Info in Area of Use of Risk Insights in Regulatory Activities.List of Attendees,Summary of Topic & Issues,Agenda & Copies of Handouts Encl ULNRC-04085, Forwards Rev 4 to Callaway Plant Cycle 10 COLR, Per TS 6.9.1.9.COLR Has Been Revised to Update Rod Bank Insertion (Ril) Limits,As Function of Rated Thermal Power1999-08-11011 August 1999 Forwards Rev 4 to Callaway Plant Cycle 10 COLR, Per TS 6.9.1.9.COLR Has Been Revised to Update Rod Bank Insertion (Ril) Limits,As Function of Rated Thermal Power ML20210P0371999-08-10010 August 1999 Forwards SE Granting Licensee 980710 Requests for Relief (ISI-13 - ISI-18) from Requirements of Section XI of 1989 Edition of ASME B&PV Code for Second 10-year Interval ISI at Plant,Unit 1 ML20210L1461999-08-0303 August 1999 Informs That NRC Plans to Administer Gfes of Written Operator Licensing Exam on 991006.Requests Submittal of Ltr Identifying Individuals Taking Exam,Personnel Allowed Access to Exams & Mailing Address for Exams ULNRC-04079, Forwards 180-day Response to NRC GL 99-02, Lab Testing of Nuclear-Grade Activated Charcoal1999-08-0202 August 1999 Forwards 180-day Response to NRC GL 99-02, Lab Testing of Nuclear-Grade Activated Charcoal ML20210H6381999-07-30030 July 1999 Forwards SE Accepting Relief Request for Approval for Use of Alternate Exam Requirement for Plant Inservice Insp Program A93443, Forwards Addl Info as Committed to in Telcon Between Amerenue & NRC Personnel on 990616,re GL 95-07, Pressure Locking & Thermal Binding of MOV Gate Valves1999-07-28028 July 1999 Forwards Addl Info as Committed to in Telcon Between Amerenue & NRC Personnel on 990616,re GL 95-07, Pressure Locking & Thermal Binding of MOV Gate Valves ULNRC-04075, Forwards Response to NRC 990618 RAI Re GL 96-05, Periodic Verification of Design-Basis Capability of SR Motor-Operated Valves1999-07-28028 July 1999 Forwards Response to NRC 990618 RAI Re GL 96-05, Periodic Verification of Design-Basis Capability of SR Motor-Operated Valves ULNRC-04076, Informs of Implementation of Amend 131 to License NPF-30, Revising OL to Reflect Requirement in TS 3/4.7.1.7 for Four Operable ASD Lines & Associated Revs,Rather than Three Operable ASDs1999-07-28028 July 1999 Informs of Implementation of Amend 131 to License NPF-30, Revising OL to Reflect Requirement in TS 3/4.7.1.7 for Four Operable ASD Lines & Associated Revs,Rather than Three Operable ASDs ULNRC-04070, Forwards Rev 3 to Callaway Plant Cycle 10 COLR, IAW TS 6.9.1.9.COLR Has Been Revised to Update RAOC Axial Flux Difference (Afd) Limits,As Function of Rated Thermal Power1999-07-27027 July 1999 Forwards Rev 3 to Callaway Plant Cycle 10 COLR, IAW TS 6.9.1.9.COLR Has Been Revised to Update RAOC Axial Flux Difference (Afd) Limits,As Function of Rated Thermal Power 05000483/LER-1998-008, Forwards Amended Response to GL 81-07, Control of Heavy Loads, to Address Corrective Action Described in LER 98-008-00.Discrepancy Between Earlier Submittals of Snupps Rept on Control of Heavy Loads & TS Re RHR Sys,Resolved1999-07-27027 July 1999 Forwards Amended Response to GL 81-07, Control of Heavy Loads, to Address Corrective Action Described in LER 98-008-00.Discrepancy Between Earlier Submittals of Snupps Rept on Control of Heavy Loads & TS Re RHR Sys,Resolved ULNRC-04071, Informs That Util Anticipates Approx Ten Licensing Actions That Could Occur During Fys 2000 & 2001,in Response to Administrative Ltr 99-021999-07-27027 July 1999 Informs That Util Anticipates Approx Ten Licensing Actions That Could Occur During Fys 2000 & 2001,in Response to Administrative Ltr 99-02 ML20210B5611999-07-20020 July 1999 Forwards Review of Ltr & Encl Objectives for Plant,Unit 1,1999 Emergency Plan Exercise Scheduled for 990914 ML20210B4021999-07-19019 July 1999 Ack Receipt of Facility Emergency Plan Implementing Procedure EIP-ZZ-00101, Classification of Emergencies, Rev 23,issued on 990513,under Provisions of 10CFR50,App E, Section V ML20210B4401999-07-19019 July 1999 Ack Receipt of Revs to Facility Radiological Emergency Response Plan,Chapters 8.0 & 4.0,issued Respectively on 990512-14,under Provisions of 10CFR50,App E,Section V ML20212A3291999-07-15015 July 1999 Forwards Scenario Manual Containing Description of Callaway Plant 1999 Biennial Emergency Response Plan Exercise to Be Conducted 990914.Correspondence to Satisfy 60-day Submittal Requirement ML20209F3471999-07-0909 July 1999 Forwards Response to NRC 990624 RAI to Complete NRC Review of Relief Request to Allow Use of 1998 Edition of ASME Section Xi,Subsection IWE ML20209E5591999-07-0808 July 1999 Informs That as Result of NRC Review of Util Responses to GL 92-01,rev 1,suppl 1 & Suppl 1 Rai,Staff Revised Info in Reactor Vessel Integrity Database & Releasing Database as Rvid Version 2.TAC MA0531 Closed ML20209H2471999-07-0707 July 1999 Forwards Rev 29 to Physical Security Plan,Per 10CFR50.54(p). Rev Withheld,Per 10CFR73.21 ML20196J9501999-07-0202 July 1999 Ack Receipt of Plant Ep,Rev 22,received on 981207 & Submitted Under Provision of 10CFR50,App E,Section V.Changes Does Not Decrease Effectiveness of EP & Continues to Meet Stds of 10CFR50.47(b).NRC Approval Not Required ML20209B6851999-06-28028 June 1999 Responds to GL 98-01,Suppl 1, Y2K Readiness of Computer Systems at Nuclear Power Plants. Disclosure Rept Encl ML20209C0171999-06-28028 June 1999 Forwards Special Rept 99-01 Re Fifteenth Year Inservice Containment Bldg Tendon Surveillance Failure.Observed Voids in Sheathing Filler Grease Do Not Indicate Degradation of post-tensioning Sys,Based on Encl Evaluation ML20196F8101999-06-25025 June 1999 Informs That J Donohew Will Assume Project Manager Responsibilities,Effective 990621 ML20196H2521999-06-25025 June 1999 Forwards Insp Rept 50-483/99-05 on 990502-0612.Two Violations Occurred & Being Treated as Noncited Violations, Consistent with App C of Enforcement Policy ML20196F8181999-06-24024 June 1999 Forwards RAI Re 990111 Request for Relief from Certain ASME Code ISI Requirements for Containment Liners.Response Requested within 30 Days from Date of Agreement ML20196G5621999-06-21021 June 1999 Informs NRC of Implementation of Amend 132 to Callaway License NPF-30 to Allows Installation of Electrosleeves for Steam Generator Tube Repair for Two Cycles Following Installation of First Electrosleeve IR 05000483/19990041999-06-18018 June 1999 Refers to GL 96-05 Issued by NRC on 960918,UE Responses & 970313 & NRC Insp Rept 50-483/99-04,dtd 990427. Forwards Request for Addl Info Re GL 96-05 Program at Callaway Plant,Unit 1 ML20212J2441999-06-18018 June 1999 Submits Request for Alternate Exam Requirements for Plant Re ISI Program Plan.Plant Does Not Torque Bolted Connections to Stress Values Greater than 100 Ksi ML20195H0971999-06-14014 June 1999 Discusses Une 990407 Request That Proprietary Document Entitled, Thermal Stability Assessment - Electrosleeved Tubes, Be Withheld from Public Disclosure.Determined Info to Be Proprietary & Will Be Withheld from Public Disclosure ML20207H3751999-06-14014 June 1999 Discusses 990407 Une Request That Proprietary Version of Document Entitled, Evaluation of Severe Accident Simulation, Dtd April 1999,be Withheld from Public Disclosure.Determined Info Proprietary & Will Be Withheld ML20195H9731999-06-11011 June 1999 Forwards Requested Addl Info Related to Relief Request ISI-16,encountered During Refuel 9 ML20195J9301999-06-0808 June 1999 Informs That Refuel 9 OAR-1 Owners Data Rept for ISI & Summary Rept for Interval 2 Was Submitted with Typographical Error,In That Commercial Service Date Should Be 841219,vice 941219.Please Substitute Encl Corrected Document ML20207G3201999-06-0707 June 1999 Ack Receipt of Change Notice 98-008 Dtd 980918,which Transmitted Changes to Callaway Plant Ep,Rev 21,under Provisions of 10CFR50,App E,Section V.No NRC Approval Required.No Violations Identified ML20207G3151999-06-0707 June 1999 Ack Receipt of Callaway Plant EP Implementing Procedure EIP-ZZ-001001M,Classification of Emergencies,Rev 22,issued on 981222 Under 10CFR50,App E,Section V Provisions.No Violations Identified ML20195C5131999-05-28028 May 1999 Forwards Revs to Sections 3.9 & 5.6 of Its,Based on Resolution Telcons Held Between NRC Staff & Util on 990526 & 27 A98803, Forwards Certified ITS & ITS Bases for Callaway Plant,In Response to NRC 990402 Draft SE for License Amend to Convert TSs to Format & Expanded Bases of ITS1999-05-27027 May 1999 Forwards Certified ITS & ITS Bases for Callaway Plant,In Response to NRC 990402 Draft SE for License Amend to Convert TSs to Format & Expanded Bases of ITS 1999-09-22
[Table view] Category:NRC TO PUBLIC ENTITY/CITIZEN/ORGANIZATION/MEDIA
MONTHYEARML20195G2121988-11-0808 November 1988 Final Response to FOIA Request for Documents.Forwards App D Document & Releasable Portions of Documents E/1 Through E/3. App D & Releasable Portions of Documents E/4 Through E/6 Available in Pdr.Portions Withheld (Ref FOIA Exemption 5) NUREG/CR-5009, Forwards NUREG/CR-5009, Assessment of Use of Extended Burnup Fuel in Lwrs. Rept Concludes That Environmentally, Burnup Increase Would Have No Significant Impact Over That of Normal Burnup.W/O Encl1988-10-26026 October 1988 Forwards NUREG/CR-5009, Assessment of Use of Extended Burnup Fuel in Lwrs. Rept Concludes That Environmentally, Burnup Increase Would Have No Significant Impact Over That of Normal Burnup.W/O Encl ML20205S3841988-10-13013 October 1988 Partial Response to FOIA Request for Documents.App D,E & F Records Encl & Available in Pdr.App F Records Partially Withheld (Ref FOIA Exemption 6) ML20236V5241987-11-18018 November 1987 Forwards 870806 SALP Rept,In Response to Question Re Performance of Plant ML20236D1691987-10-21021 October 1987 Responds to Re Replacement of Fuel Rods W/Filler Rods & Vantage-5 Fuel for Cycle 3 Operation at Facility.Encl Safety Evaluation Discusses Safety Considerations That Were Evaluated Before Approving Util Application IA-84-901, Final Response to FOIA Request Re Plant Proposed Civil Penalty.Forwards App B & D Documents.App B & C Documents Partially & Completely Withheld,Respectively (Ref FOIA Exemptions 5 & 7).App B,D & E Documents Available in PDR1987-05-26026 May 1987 Final Response to FOIA Request Re Plant Proposed Civil Penalty.Forwards App B & D Documents.App B & C Documents Partially & Completely Withheld,Respectively (Ref FOIA Exemptions 5 & 7).App B,D & E Documents Available in PDR ML20214L0681987-05-26026 May 1987 Final Response to FOIA Request Re Plant Proposed Civil Penalty.Forwards App B & D Documents.App B & C Documents Partially & Completely Withheld,Respectively (Ref FOIA Exemptions 5 & 7).App B,D & E Documents Available in PDR ML20214F9491987-05-15015 May 1987 Requests Notification Re Whether Organization Wishes to Remain on Mailing List for Facility Info within 30 Days of Ltr Receipt ML20214F6431987-05-15015 May 1987 Requests Notification of Wish to Remain on Mailing List to Receive Info Re Facility within 30 Days of Ltr Receipt or Name Will Be Removed from List ML20214F6021987-05-15015 May 1987 Requests Ltr Notifying NRC of Wish to Remain on Mailing List & to Continue to Receive Info Re Facility within 30 Days of Ltr Receipt ML20215H8901987-05-0505 May 1987 Sixth Partial Response to FOIA Request for Documents Re Allegations.Forwards App C & D Documents.App B Documents Also Available in PDR ML20206P1391987-04-16016 April 1987 Partial Response to FOIA Request for Info.Forwards App a Documents.App a Documents Also Being Made Available in PDR ML20203N3701986-09-26026 September 1986 Fourth Partial Response to FOIA Request for Region IV Allegation Data Forms & Background Records.Portions of App E & F Documents Forwarded & Available in PDR & App G & H Documents Withheld (Ref FOIA Exemptions 6 & 7) ML20206G7401986-06-18018 June 1986 Partial Response to FOIA Request for Documents Re Cases Pertaining to Plant from 830101-850820.App a Documents in Pdr.Forwards App B Documents ML20198E6491986-05-0808 May 1986 Partial Response to FOIA Request for All Internal Documents Re IE Info Notice 86-005 & Operability of Main Steam Safety Valves.Encl App a Documents Available in Pdr.App B Documents Being Placed in PDR IA-85-655, Final Response to FOIA Request for Four Categories of Documents Re QC at Facility.Documents Listed in App D Completely Withheld (Ref FOIA Exemptions 5 & 7)1986-01-0303 January 1986 Final Response to FOIA Request for Four Categories of Documents Re QC at Facility.Documents Listed in App D Completely Withheld (Ref FOIA Exemptions 5 & 7) ML20137X0501986-01-0303 January 1986 Final Response to FOIA Request for Four Categories of Documents Re QC at Facility.Documents Listed in App D Completely Withheld (Ref FOIA Exemptions 5 & 7) ML20138J7821985-12-11011 December 1985 Requests Notification within 1 Month of Ltr Date If Continued Svc of Documents & Correspondence Desired.Party Will Be Automatically Taken Off Svc List If Notification Not Received ML20138K0491985-12-11011 December 1985 Advises That Copies of NRC Correspondence to Util Will Not Be Sent Since Proceedings to Which Coalition for Environ Intervening Party Completed & OL Issued for Facility ML20138K6091985-12-11011 December 1985 Informs That Documents Filed by Licensee & Correspondence from NRC Re Operation of Facility Will Continue to Be Made Available in NRC & Lpdr.Nrc Will Discontinue Sending Copies as OL Proceedings Completed ML20138M3241985-12-11011 December 1985 Informs That Documents Filed by Licensee & Correspondence from NRC Re Operation of Facility Will Be Available in NRC & Lpdr.Nrc Will Discontinue Sending Copies as OL Proceedings Completed ML20134A6201985-10-22022 October 1985 Further Response to FOIA Request for Four Categories of Documents Re Plant Qc.Forwards Documents Listed on Apps B & C.Portions of App C Documents Withheld (Ref FOIA Exemptions 6 & 7) ML20133J4901985-10-11011 October 1985 Partial Response to FOIA Request for Four Categories of Documents Re QC at Facility.Documents on App a Available in Pdr.Search Continuing ML20135G4161985-08-0707 August 1985 Responds to FOIA Request for Four Categories of Documents Re Philippine Nuclear Power Plant.App a Documents Encl.App B Documents Available at Pdr.App C Document Withheld (Ref FOIA Exemption 4) NUREG-0748, Responds to FOIA Request for Four Categories of Documents Re Philippine Nuclear Power Plant.App a Documents Encl.App B Documents Available at Pdr.App C Document Withheld (Ref FOIA Exemption 4)1985-08-0707 August 1985 Responds to FOIA Request for Four Categories of Documents Re Philippine Nuclear Power Plant.App a Documents Encl.App B Documents Available at Pdr.App C Document Withheld (Ref FOIA Exemption 4) IA-84-701, Further Response to FOIA Request for Documents Generated During 840612 Interviews Re Facility or Specific Allegations Made During Interviews.Forwards App a Documents.Documents Also Available in PDR1985-07-22022 July 1985 Further Response to FOIA Request for Documents Generated During 840612 Interviews Re Facility or Specific Allegations Made During Interviews.Forwards App a Documents.Documents Also Available in PDR ML20134D6761985-07-22022 July 1985 Further Response to FOIA Request for Documents Generated During 840612 Interviews Re Facility or Specific Allegations Made During Interviews.Forwards App a Documents.Documents Also Available in PDR IR 05000483/19850021985-07-15015 July 1985 Notifies That Insp of Concerns Noted in Re Certification of Level III Inspectors Completed & Documented in Paragraph 4 of Encl Insp Rept 50-483/85-02.Info Deleted ML20133H6171985-06-27027 June 1985 Final Response to FOIA Requests for Documents Re Contacts Between Nrc/Doe & White House Officials Concerning Callaway, Diablo Canyon & Shearon Harris Plants.Forwards Listed Documents.Documents Also in PDR IA-85-354, Final Response to FOIA Requests for Documents Re Contacts Between Nrc/Doe & White House Officials Concerning Callaway, Diablo Canyon & Shearon Harris Plants.Forwards Listed Documents.Documents Also in PDR1985-06-27027 June 1985 Final Response to FOIA Requests for Documents Re Contacts Between Nrc/Doe & White House Officials Concerning Callaway, Diablo Canyon & Shearon Harris Plants.Forwards Listed Documents.Documents Also in PDR IA-84-355, Further Response to FOIA Request for Documents Re Contacts Between Doe/Nrc & White House,Utils,State Regulatory Agencies & Financial Community Concerning Facilities. Forwards Listed Documents.Documents Also in PDR1985-06-17017 June 1985 Further Response to FOIA Request for Documents Re Contacts Between Doe/Nrc & White House,Utils,State Regulatory Agencies & Financial Community Concerning Facilities. Forwards Listed Documents.Documents Also in PDR ML20128Q6911985-06-17017 June 1985 Further Response to FOIA Request for Documents Re Contacts Between Doe/Nrc & White House,Utils,State Regulatory Agencies & Financial Community Concerning Facilities. Forwards Listed Documents.Documents Also in PDR ML20126F3821985-06-14014 June 1985 Advises That Time for Commission to Review Director'S Decision DD-85-7 Expired.Commission Declined Review.Decision Became Final Agency Action on 850611.Served on 850617 IA-85-355, Responds to FOIA Requests for Records Re Contacts W/Federal Govt,State Regulatory Commissions,Util & Financial Community Concerning OLs for Facilities.Listed Document Available in Pdr.Search for Addl Documents Still in Progress1985-06-10010 June 1985 Responds to FOIA Requests for Records Re Contacts W/Federal Govt,State Regulatory Commissions,Util & Financial Community Concerning OLs for Facilities.Listed Document Available in Pdr.Search for Addl Documents Still in Progress ML20129A1811985-06-10010 June 1985 Responds to FOIA Requests for Records Re Contacts W/Federal Govt,State Regulatory Commissions,Util & Financial Community Concerning OLs for Facilities.Listed Document Available in Pdr.Search for Addl Documents Still in Progress ML20128P9271985-05-15015 May 1985 Responds to FOIA Request for Any & All Records Re Insp Rept 50-483/84-45.Forwards App a Documents.Info Available in Pdr.App B Document Partialy Withheld (Ref FOIA Exemption 5) ML20127D9171985-05-10010 May 1985 Ack Receipt of 850326 Request for Action Under 10CFR2.206 for Order to Show Cause Why OL Should Not Be Suspended or Revoked Due to Qualification of Const & Operations QA Personnel ML20126H3351985-04-15015 April 1985 Responds to FOIA Request for Documents Re Electrical Cable Separation Deficiencies at Facility.Forwards Apps a & B Documents.Documents Also Available in PDR ML20126E1931985-03-11011 March 1985 Responds to FOIA Request for Five Categories of Documents. Forwards Documents Listed on App.Documents Also Available in PDR ML20134A6281985-02-13013 February 1985 Forwards Memo Documenting Concerns Re Certification of Level III Inspectors Per .Concerns Assigned to Region III for Resolution.Insps Will Be Completed within 90 Days. Info Deleted ML20127C4351985-01-11011 January 1985 Informs That Considerable Insp Resources Expended to Pursue Matters Raised in 840928 Petition.Decision Will Be Issued on Petition After Insp Efforts & Evaluation of Results Completed IR 05000483/19840301984-09-28028 September 1984 Partially Withheld Ltr Extending Appreciation for Cooperation Re Const Deficiencies.Insp Rept 50-483/84-30 Discussing Technical Concerns Encl.Other Concerns Forwarded to Regions II & IV ML20148G5501978-11-0303 November 1978 Responds to to Rc Deyoung Re Review of Site & Its Relationship to New Madrid Fault.Repts That Aslp Concluded Favorably on All Aspects of Plant Constr Permit Appl W/Copy of from Drs Nieto & Cording 1988-11-08
[Table view] Category:OUTGOING CORRESPONDENCE
MONTHYEARML20217K1051999-10-19019 October 1999 Ack Receipt of Ltr Dtd 990707,which Transmitted Rev 29 to Callaway Plant Physical Security Plan,Under Provisions of 10CFR50.54(p).Based on Determination That Changes Do Not Decrease Effectiveness of Plan,No NRC Approval Required ML20217G2071999-10-14014 October 1999 Forwards Insp Rept 50-483/99-10 on 990913-16.No Violations Noted.Insp Was to Review Emergency Plan & Procedures During Biennial Emergency Preparedness Exercise ML20217B5901999-10-0505 October 1999 Informs That Staff Concludes That Licensee Responses to GL 97-06 Provides Reasonable Assurance That Condition of Util SG Internals in Compliance with Current Licensing Bases for Callaway Plant,Unit 1 ML20217B5711999-10-0505 October 1999 Discusses GL 98-01 Issued by NRC on 980511 & Uec Responses for Callaway NPP Unit 1 ,990224 & 990628.Informs That Staff Reviewed Responses & Concluded That All Requested Info for GL 98-01 Provided ML20212G0221999-09-22022 September 1999 Forwards Insp Rept 50-483/99-11 on 990812-20.No Violations Noted.Team Found,Weakness in flow-accelerated Corrosion Monitoring Program Resulted in No Previous Insp of Pipe Segment Which Failed ML20212D9341999-09-16016 September 1999 Informs That on 990818,NRC Completed Midcycle PPR of Callaway Plant.In Area of Ep,C/As Taken in Response to Problems Identified During Previous Exercises Warrant More in-dept Review.Details of Insp Plan Through March 2000 Encl ML20212A4921999-09-13013 September 1999 Forwards Insp Rept 50-483/99-08 on 990725-0904.Two Severity Level IV Violations of NRC Requirements Identified & Being Treated as Noncited Violations Consistent with App C of Enforcement Policy ML20212B1521999-09-10010 September 1999 Forwards Insp Rept 50-483/99-07 on 990809-13.No Violations Noted.Inspectors Used Annual Licensed Operator Requalification Exams to Assess Licensed Operator Performance ML20211N0321999-09-0202 September 1999 Forwards SE Concluding That Util Adequately Addressed Actions Requested in GL 95-07, Pressure Locking & Thermal Binding of Safety-Related Power-Operated Gate Valves ML20211B0241999-08-18018 August 1999 Ack Receipt of Ltr Dtd 990714,transmitting Scenario for Licensee Upcoming Biennial Exercise.Based on Review,Nrc Determined That Exercise Scenario Sufficient to Meet Emergency Plan Requirements & Exercise Objectives ML20210T9121999-08-13013 August 1999 Forwards Insp Rept 50-483/99-06 on 990613-0724.One Severity Level 4 Violation Occurred & Being Treated as Ncv,Consistent with App C of Enforcement Policy ML20211A9501999-08-12012 August 1999 Discusses 990720-21 Workshop Conducted in Region IV Ofc,Re Exchange of Info in Area of Use of Risk Insights in Regulatory Activities.List of Attendees,Summary of Topic & Issues,Agenda & Copies of Handouts Encl ML20210P0371999-08-10010 August 1999 Forwards SE Granting Licensee 980710 Requests for Relief (ISI-13 - ISI-18) from Requirements of Section XI of 1989 Edition of ASME B&PV Code for Second 10-year Interval ISI at Plant,Unit 1 ML20210L1461999-08-0303 August 1999 Informs That NRC Plans to Administer Gfes of Written Operator Licensing Exam on 991006.Requests Submittal of Ltr Identifying Individuals Taking Exam,Personnel Allowed Access to Exams & Mailing Address for Exams ML20210H6381999-07-30030 July 1999 Forwards SE Accepting Relief Request for Approval for Use of Alternate Exam Requirement for Plant Inservice Insp Program ML20210B5611999-07-20020 July 1999 Forwards Review of Ltr & Encl Objectives for Plant,Unit 1,1999 Emergency Plan Exercise Scheduled for 990914 ML20210B4401999-07-19019 July 1999 Ack Receipt of Revs to Facility Radiological Emergency Response Plan,Chapters 8.0 & 4.0,issued Respectively on 990512-14,under Provisions of 10CFR50,App E,Section V ML20210B4021999-07-19019 July 1999 Ack Receipt of Facility Emergency Plan Implementing Procedure EIP-ZZ-00101, Classification of Emergencies, Rev 23,issued on 990513,under Provisions of 10CFR50,App E, Section V ML20209E5591999-07-0808 July 1999 Informs That as Result of NRC Review of Util Responses to GL 92-01,rev 1,suppl 1 & Suppl 1 Rai,Staff Revised Info in Reactor Vessel Integrity Database & Releasing Database as Rvid Version 2.TAC MA0531 Closed ML20196J9501999-07-0202 July 1999 Ack Receipt of Plant Ep,Rev 22,received on 981207 & Submitted Under Provision of 10CFR50,App E,Section V.Changes Does Not Decrease Effectiveness of EP & Continues to Meet Stds of 10CFR50.47(b).NRC Approval Not Required ML20196F8101999-06-25025 June 1999 Informs That J Donohew Will Assume Project Manager Responsibilities,Effective 990621 ML20196H2521999-06-25025 June 1999 Forwards Insp Rept 50-483/99-05 on 990502-0612.Two Violations Occurred & Being Treated as Noncited Violations, Consistent with App C of Enforcement Policy ML20196F8181999-06-24024 June 1999 Forwards RAI Re 990111 Request for Relief from Certain ASME Code ISI Requirements for Containment Liners.Response Requested within 30 Days from Date of Agreement IR 05000483/19990041999-06-18018 June 1999 Refers to GL 96-05 Issued by NRC on 960918,UE Responses & 970313 & NRC Insp Rept 50-483/99-04,dtd 990427. Forwards Request for Addl Info Re GL 96-05 Program at Callaway Plant,Unit 1 ML20207H3751999-06-14014 June 1999 Discusses 990407 Une Request That Proprietary Version of Document Entitled, Evaluation of Severe Accident Simulation, Dtd April 1999,be Withheld from Public Disclosure.Determined Info Proprietary & Will Be Withheld ML20195H0971999-06-14014 June 1999 Discusses Une 990407 Request That Proprietary Document Entitled, Thermal Stability Assessment - Electrosleeved Tubes, Be Withheld from Public Disclosure.Determined Info to Be Proprietary & Will Be Withheld from Public Disclosure ML20207G3151999-06-0707 June 1999 Ack Receipt of Callaway Plant EP Implementing Procedure EIP-ZZ-001001M,Classification of Emergencies,Rev 22,issued on 981222 Under 10CFR50,App E,Section V Provisions.No Violations Identified ML20207G3201999-06-0707 June 1999 Ack Receipt of Change Notice 98-008 Dtd 980918,which Transmitted Changes to Callaway Plant Ep,Rev 21,under Provisions of 10CFR50,App E,Section V.No NRC Approval Required.No Violations Identified ML20207E2711999-05-25025 May 1999 Ack Receipt of in Response to & Insp Rept Confirming Commitment as Stated by M Taylor During Telephonic Exit Meeting on 990413 ML20207A8711999-05-24024 May 1999 Informs That NRR Reorganized,Effective 990328.Forwards Organization Chart ML20207A4131999-05-19019 May 1999 Forwards Insp Rept 50-483/99-03 on 990321-0501.One Violation of NRC Requirements Identified & Being Treated as Noncited Violation,Consistent with App C of Enforcement Policy ML20206K6511999-05-10010 May 1999 Forwards RAI Re GL 96-06, Assurance of Equipment Operability & Containment Integrity During Design-Basis Accident Conditions ML20206N3981999-05-10010 May 1999 Responds to Comments & Questions Submitted to NRC Staff Re Recent License Amend Issued by NRC to Callaway Unit 1 License.Provides Context for Conclusion That Reracking of Callaway SFP Maintains Adequate Protection of Public Safety ML20206H1101999-05-0606 May 1999 Forwards Results of Gfes of Written Operator Licensing Exam, Administered on 990407,to Nominated Employees of Facility. Requests That Training Dept Forward Individual Answer Sheets & Results to Appropriate Individuals.Without Encl ML20206H1821999-05-0606 May 1999 Forwards RAI Re Licensee Request for Relief from Certain ASME Code ISI Requirements Submitted by .Response Requested within 30 Days of Receipt of Ltr ML20206F4931999-05-0303 May 1999 Forwards Exam Rept 50-483/99-302 on 990416.Insp Included Evaluation of Applicant for Reactor Operator License ML20205S2571999-04-19019 April 1999 Discusses Plans to Sponsor Testing of Electrosleeved Tubes to Better Understand Behavior of Electrosleeve Matl Under Severe Accident Conditions ML20205Q5461999-04-19019 April 1999 Forwards Safety Evaluation Relief Request from Certain ASME Section XI Requirements for Concrete Containment ISI for Plant ISI Program ML20205K7641999-04-0808 April 1999 Ack Receipt of Re Comments & Questions Concerning Recent Amend to Plant,Unit 1.Response to Comments & Questions Should Be Completed by mid-May ML20205J8701999-04-0606 April 1999 Ack Receipt of ,In Response to NRC Insp Rept 50-483/99-02,dtd 990225 Re Verbal Commitment Made During Exit Meeting for Insp.Understands Next Rev of Security Plan Will Include Increased Min Staffing of Three Armed Guards ML20205J8721999-04-0505 April 1999 Refers to Meeting Conducted in Emergency Operations Facility at Callaway Plant on 990401 Re Plant Performance Review for Plant Completed on 990211.Year 2000 Readiness Issues & New Reactor Licensee Performance Assessment Also Discussed ML20205J9401999-04-0505 April 1999 Forwards Insp Rept 50-483/99-01 on 990207-0330.One Violation Occurred & Being Treated as Noncited Violation,Consistent with App C of Enforcement Policy IR 05000019/20250011999-04-0202 April 1999 Informs That Version of Topical Rept BAW-10219P,Rev 3 Dtd Oct 1998 & Document 51-5001925-01,dtd 980828 Will Be Marked as Proprietary & Be Withheld from Public Disclosure Pursuant to 10CFR2.790(b)(5) & Section 103(b) of Atomic Energy Act ML20205A3821999-03-19019 March 1999 Advises of NRC Planned Insp Effort Resulting from Callaway Plant Performance Review for Period 970510-990125. Historical Listing of Plant Issues & Details of NRC Insp Plan for Next 8 Months Encl ML20204E7281999-03-18018 March 1999 Ack Receipt of Which Transmitted Rev 28 to Callaway Plant Physical Security Plan,Per 10CFR50.54(p).No NRC Approval Is Required,Since Util Determined Changes Do Not Decrease Effectiveness of Plan ML20204E3671999-03-18018 March 1999 Informs That During 990128 Telcon Between D Lantz & H Bundy, Arrangements Were Made for Administration of Retake Written Operator Licensing Exam at Plant,During Wk of 990419 ML20204B7091999-03-15015 March 1999 Informs That Changes Described in ,Submitting Rev 20 to Plant Operational QA Manual,Appear Consistent with Guidelines for non-reduction in Committments ML20204C4241999-03-15015 March 1999 Forwards Request for Addl Info Re GL 95-07, Pressure Locking & Thermal Binding of Safety-Related Power-Operated Gate Valves ML20207F4731999-03-0404 March 1999 Discusses 990302 Public Meeting Re Program Updates & Organizational Changes in Emergency Preparedness & Security. List of Attendees & Licensee Presentation Encl ML20207L6491999-03-0404 March 1999 Informs That Util 990111 Response to Request for Addl Info Re Question 4 Will Be Marked as Proprietary & Will Be Withheld from Public Disclosure Pursuant to 10CFR2.709(b)(5) & Section 103(b) of Atomic Energy Act of 1954,as Amended 1999-09-22
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% UNITED S T ATES y s* f' ; NUCLEAR REGULATORY COMMISSION
.J ) j WASHINCTON, D. C. 20555 O2SQ,f s.- ...
NOV 0 31978 Docket Nos. STN 50-483 and STN 50-486 Mrs. Leo Drey 515 West Point Ave. ,
University City, Missouri 63130 I
Dear Mrs. Drey:
Your letter, dated October 18, 1978, to Mr. R. C. DeYoung has been referred to me for a reply. In your letter, you (1) request certain documents relating to our review cf the site for the Callaway Plant, Units 1 and 2, (2) discuss the review of the Callaway site performed by our consultants, Drs. E. J. Cording and A. Nieto, and (3) refer to a recent radio program wherein the closeness of the New Madrid fault to the Callaway plant site was discussed. Our responses to your .
requests and to the comments made in your letter are presented in the following paragraphs.
In your letter, you refer to a letter, dated February 11, 1974, fron Mr. R. C. DeYoung to Mr. Nicholas Petrick, Executive Director of SNUPPS and requested a copy of the SNUPPS answer to that letter. The SNUPPS -
utilities in a letter dated October 29, 1973, requested the staff to review information regarding the characteristics of the four proposed SNUPPS sites, including the site for the Callaway plant. It was o understood that the review by the staff would enable the SNUPPS utilities to improve the quality of their Preliminary Safety Analysis Reports (PSAR) and thereby conserve staff manpower in the review effort. The February ll,1974 letter provided the staff's comments on the information supplied by the SNUPPS utilities. The SNUPPS utilities did not provide documentation which specifically addressed those comments but did consider the comments during the preparation of the PSAR's.
Our construction permit review of the four SNUPPS applications, including the Callaway application, was performed on the basis of the information provided in the SNUPPS PSAR's and the amendments thereto. As a result of our review of the Callaway PSAR and its amendments, we were able to conclude that the seismic design bases for the La11away plant are appropriately conservative for the earthquake potential at the Callaway ,
site. This conclusion considered the proximity of the New Madrid fault zone (Mississippi Embayment seismic zone) conservatively estimating
' that this zone comes no closer than 155 miles southwest of the site.
781113 Olo7
1 Mrs. Drey fl0V 0 31978 The conclusions resulting from our review of the Callaway site are documented in the staff's Safety Evaluation Report (SER) for Callaway.
Copies of the Callaway PSAR, the staff's SER for Callaway, and Supplement No. I to the SER are available for public inspection at the V. S.
Nuclear Regulatory Commission's Public Document Room,1717 H Street, N. W. , Washington, D. C. 20555; at the Fulton City Library, 209 Market Street, Fulton, Missouri 65251; and at the Olin Library of Washington University, Skinker and Lindell Boulevards, St. Louis, Missouri 63130.
We are enclosing a copy of the October 2,1975 letter from Drs. Nieto and Cording as you requested. As indicated in that letter, Drs. Nieto and Cording concluded that while it is unlikely that large open cavities are present below the Callaway site which could cause subsidence or settlement, additional borings would be required to ascertain that no large cavities are present.
Subsequently in the Callaway Public Hearings on December 10, 1975, Dr. Cording stated that, based on additional information obtained from geologists with the Missouri Geological Survey, he concluded that the Callaway site was adequate without additional borings. Furthermore, both Drs. Nieto and Cording stated that they agreed with the staff's conclusion presented in Supplement No. 1 to the Callaway SER, that the potential for the existence of large cavities beneath the Callaway site was very remote and, therefore, does not constitute a hazard. As a result of the staff's and NRC consultants' evaluation, as discussed above, no additional borings were required.
In its Initial Decision, dated April 8,1976, the Atomic Safety and Licensing Board concluded favorably on all aspects of the Callaway plant construction permit application. Specifically with regard to postulated large cavities beneath the Callaway site, the Board found that the potential for subsidence at the site was remote and did not constitute a safety hazard. As a result of the Board's Initial Decision, we subsequently granted the construction permits for the Callaway plant.
We believe that the above information is responsive to your request.
Sincerely, b% hb Olan D. Parr, Chief Light Water Reactors Branch Nc. 3 Division of Project Management
' E ncl osure:
Letter, dated 10/2/75 from Drs. E. J. Cording and A. Nieto
'., ,. , . ALEERTO in L TO Elm /d:D o. ^ E D ! h ^,
000 technical Censultant Geotechoical ::'sul ant il3b Natural History , , 100? Pr/ fi.-
Urbana, il 61801 Champa ic,n , IL 618'O Phone: 217-333-1068 Phone: 217-333-6933 CISG 2 October 1975 1
i U. S. Nuclear Regulatory Cornission ATIN: Mr. Richard C. T'ullen Division of Technical Review I Wash ington , D.C. 20555
- REF: P0 DR 76-0296, Callaway Units 1 and 2
Dear Sir:
We have summarized in this joint letter repart the infer ;; tion re;uested in the referenced purchase order. We were requested to evalu?te "tha patential for subsidence or collapse et the plant site due to the possibili:/ of cavities below a depth of senral hundecd feet beneath the site." Specifically we were l asked to provide assistance to:
1 -
) "(1) determine the r:axirum size void that could edst oithin the uppcr several hundred feet cnd rcmin undetected by the exploratory techniques at the site,.and (2) determine whether or not such a r:axirm ' cavit:. ceuld c.use surface subsidence or collapse under both static condi ticns and conditions imposed by the safe shutdown carthquale "
Our in'.estigation has been directed to.;ard evalue u.n ci ti.o potential for cavities br. low the base of the Callaway formation (belew a depth of approximately 150 ft).
- 1. Boring Information Twenty borings extended through the overlying Callaway For.:atien. Of these, six extended over 100 ft below the base of the Callauay Fr" ration.
Four of these six borinns (P-70, P-69, P-148, and P-/4) have been drilled to approxima tely 250 f t l'elow the base of the Callaway fonn ti n. P. 8 is 200
_ - __ _ - - - _ - _ _ - _ _ -_ _ - _ - _ _ - - - - - - __ 7--
l
.- U..S. lluclear Regulatory Commission 2 October 1975 I Page -Two-i ft from P-70, as is P-148 from P-74. A line connecting the first tuo l
boreholes is about 400 f t away from a line connecting the last two.
The spacing of the boreholes is large enough that there is little restriction on the position or maximum size of a cavity that might exist below the Callaway Formation. Thus the boring information does not directly
, indicate the absence of large caverns (approxinately 100 to 150 f t wide) at l the site. In order to conclude that large caverns are absent, several assumptions must be made regarding the geologic conditions under which caverns might form. We agree with the applicant that it is unlikely that large caverns exist in the Cotter-Jefferson City Formation. However, varying interpretations of the geologic information can be made, and we feel that arguments can be l
l advanced for the presence of open cavities below the Callaway Forntion at the site.
- 2. Airphoto Information Assuming cavities are present there is no evidence from airphotos of the plant site that the features have propagated to the surface and formed sinks. Any sinks that may have formed in the past have existed long enough to be filled and or er ded so that triey are no . longer discernable. Thus it is probable thc rge open cavities are either not present or if present ha'ic been st kce a pericd of time isngcr than !".c time requ: red to 'i!'
or erode the sinks at the surface.
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. ~m m em n * -+
U. 5. I!uclear Regulatory Comission 2 October 1975 Page -Three-
- 3. Cotter-Jefferson Citv Forma tion Core recovered below the base of the Callaway reveals the presence of at least two paleokarst features in the Cotter-Jefferson City. These features have estimated diameters of 250 and 150 feet and thicknesses of about 100-150 fc>t. The fill in the features is St. Peter sa'ndstone with 30-50 f t of paleo-karst rubble lining the lower portion. Several of these features are exposed 1
in the bluffs along the Missicur River. The applicant indicates that no open cavities greater than a few inches were observed during drilling in the
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Cotter-Jef ferson City at the site or in the plant area.
Core recoveries and RQD were high. Although no open solutico features were observed in the Cotter-Jefferson City at the plant site, it should be noted that the exploration and exposures of the Cotter-Jefferson City have been linited. Solution features are known to exist in the Cotter-Jefferson City within less than 80 miles' of the site. '
- 4. Gasconade Formation The Gasconade Formation appears to have a greater tendency to develop open solution cavities than the Cotter-Jefferson City. At the site, the Gasconade Formation is located below the Cotter-Jef ferson City at a depth of 700 f t. It is possible that solution cavities have developed in the Gasconado due to deep ground water flow of undersaturated water.
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'5. Size and Depth of Cavities That Could Cause Surface ."ns : ents The range of cavern widths that are of concern at the site is estimated to be 100 to 150 ft. Most existing caverns have spans less D
U. S. Nuclear Regulatory Comission 2 October 1975 Page -Four-l ,
than 150 ft. It is estimated that the span of the cavern would have to be greater than 100 f t for a cavern collapse to proceed up through rassive-bedded Callaway Limestone.
The depth to the roof of caverns that might cause subsidence or sinks aL the ground surface is estimated to be 400 f t, assuming that the largest cavity beneath the site would have a height of 100 f t and that progressive collapse of the cavity would result in 25% bulking of the debris. It is therefore considered that any solution cavities that might exist in the Gascona, ,
formation, will not result in subsidence at the ground surface.
l Propagation of cavities toward the surface could result from:
- 1. increase in cavity span by solutioning
- 2. removal of bouyant forces in cavern (lowering of ground water table);
seepage in roof
- 3. solutioning along roof joints ,
- 4. seismic activity
- 5. time-dependent sagging and slabbing of walls and roof.
The additional load placed on deep cavities by the structures at the Callaway site will not significantly change the stability of the caverns. ,
Conclusion l 6.
l It is unlikely that open cavities are present belou the Caiiauiy l
,. Formation that will cause subsidence or settlement at the ground surface.
Houever, taking a pessimistic view of the geologic evidence, the presence of large caverns in the Cetter-Jef ferson City can be postulated. !
l 3
U 3. Nuclear Regulatory Comission 2 October 1975 Page -Five-There are few deep borings in the vicinity of the reactor vessels, and the spacing of deep borings is such that there is only a small probability that one of the borings would have intersectcJ a cavern of 100 to 150 f t.
Solution zones connected to the caverns coul,d also be missed by the deep borings. In order to determine that no large caverns, that could cause subsidence at the surface, exist below critical structures, borings spaced on I the order of 100 f t apart and extending to a depth of 450 f t would be required. In the vicinity of each containment vessel, approxiccately 6 to 8 additional borings would be required, in a pattern extending out 40 f t beyond the perimeter of the reactor.
We have considered the possibility of installing a monitoring system to provide early warning of a potential collapse .or surface settlement. It is our conclusion that the effort required in installing a r.onitoring system is equivalent to that required, for direct exploration. We therefore recom end the boring alternative. Appendix A summarizes our conclusions regarding an instrumentation system.
This report is intended as a summary or our investigation, ue will be happy to p avide more detail on the various aspects of this problem.
Sincerely yours, .,
J ) .? / '
AN/MC4/M. $$$!% /
Edward J. Corping b//N[GyQ Alberto S. Nieto EJC/jrm l
l
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Appendix A: !!onitoring i
It is our conclusion that surface bench marks do not provide adequate warning becau~.0, by the time surface novements are occurring, the possibility of imminent collapse is likely. For very large mined areas, a wave of syrface subsidence precedes collapse, so that warning can be obtained at the ground surface. For sinks where the depth is great with respect to the diameter, the sink will rapidly reach the ground surface once surface movements are
. observed. Deep anchors in and below the Callaway would provide earlier warning because they would be nearer the source of movement and would be more precise and interpretable at an earlier date. Rod-type extensometers 150- f t deep would be required. Extensometers of such length have been installed on several projects to monitor displacements with a precision of 0.01 in, or better. The techr.iques of installing and using such extensometers are well established.
If the stoping process were very rapid -- then even extensometers would not be adequate. A case has been observed where a 200 ft x 200 ft room and pillar mined area broke vertically 350 ft to the surface through Mississippian shales and limestones in a period of less than i day (probably less than ar hour). The collapse was thought to have been ' triggered by the overloading of the pillars. One pillar failed resulting in overloading and failure of the others. Collapse to the surface was rapid because the roof had a factor of safety considerably less than one once the pillars were gone.
The liiass failed witii very lii.tle bulking. Ai. icosi. 50.5 of the volun:e ui the 15 ft high cavern developed in the sink at the surface.
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For the case of a solutiori cavern that has been stable for a long period, the progression of the cave to the surface should proceed over a longer period, by sag and slabbing of individual beds. Thus conitoring could
be carried out with deep extensometerr, located over the cas.;/. Existing caves show evidence of progressive siahbing. Pronressive failures can also be observed mines and tunnels. In one abr ed railroad tunnel, in Pennsylvanian 'es and sandstones the rool ,obed upward 30 ft above the c rown, form #
ft-wide chimney,and stabilized against a thicker sandstone layer.
Extensometers would provide warning for caverns that are below the
. boring depth. (However, as explained earlier, we feel that borings to 450 f t will provide adequate depth exploration for potential caves). Extensometers with multiple anchors would provide some warning for caves away from the borehole which could influence structure. However the evidence is that the sink would proceed almost vertically until it encountered the shallow soils. The exten-someters would record very little movement if a cavern adjacent to the extensoneters was propagating vertically to the surface. Thus it is con-cluded that the extensometers would not provide inforret ion n addition to that obtainable from borings.
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