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Category:CORRESPONDENCE-LETTERS
MONTHYEARML20217H4661999-10-18018 October 1999 Forwards Changes to EPIPs IAW 10CFR50.54(q) & 10CFR50,App E, Section V.Details of Changes Encl ML20216J8241999-09-30030 September 1999 Notifies of Removal of NRC Headquarters & Region III Offices from Controlled Copy Distribution of Certain CE Documents. Specific Documents,Associated Controlled Copy Numbers & NRC Location Affected Are Shown on Attachment to Ltr ML20211G1221999-08-27027 August 1999 Forwards fitness-for-duty Program Performance Data for Each of Comm Ed Nuclear Power Stations & Corporate Support Employees within Scope of Rule for six-month Period Ending 990630,IAW 10CFR26.71(d) ML20210N5651999-08-0606 August 1999 Forwards Rev 8 to Nuclear Generating Stations Emergency Plan, for Plants.With Summary of Changes ML20210M9131999-08-0202 August 1999 Forwards Response to NRC AL 99-02, Operating Reactor Licensing Action Estimates, for Fys 2000 & 2001 for Comed ML20210L1061999-08-0202 August 1999 Forwards Insp Rept 50-010/99-13 on 990702-27.No Violations Noted.Insp Examined Activities in Areas of Facility Management & Control & Radiological Safety ML20210D2961999-07-20020 July 1999 Forwards Corrected Info for DNPS Unit 3 MOR for June 1999. Year-to Date Forced Outage Hours Should Have Read 70 Hours Instead of 0 on Page 8.Error Also Affected Cumulative Forced Outage Hours Which Should Have Been 24,761 ML20210B7071999-07-16016 July 1999 Responds to Requesting Review & Approval of Three Proposed Changes to Ceco QA TR,CE-1A Per 10CFR50.54(a)(3) & 10CFR50.4(b)(7) ML20196J9131999-07-0101 July 1999 Submits Status of Nuclear Property Insurance Currently Maintained for Braidwood,Byron,Dresden,Lasalle County,Quad Cities & Zion Nuclear Power Stations,Per 10CFR50.54(w)(3) ML20196J9061999-07-0101 July 1999 Provides Evidence That Util Maintains Guarantee of Payment of Deferred Premiums in Amount of $10 Million for Each of Thirteen Reactors,Per 10CFR140.21 ML20196K3231999-06-30030 June 1999 Informs That Effective 990703,NRC Project Management Responsibility for Dresden,Unit 1 Station Will Be Transferred to P Ray ML20209B8241999-06-30030 June 1999 Forwards Five 3.5 Inch Computer Diskettes Containing Revised Annual Dose Repts for 1994 Through 1998 for Individuals Receiving Neutron Dose Not Previously Included in Reported Total Effective Dose Equivalent Values.Without Diskettes ML20196D3491999-06-18018 June 1999 Forwards Insp Repts 50-237/99-08 & 50-249/99-08 on 990408-0521.Four Non-Cited Violations Noted.Maint on safety- Related Emergency CR Not Performed Well.Low Impact Issues Re Communications Present in Operations,Maint & Security ML20212J0541999-06-17017 June 1999 Responds to Requesting That NRC Staff ...Allow BWR Plants Identified to Defer Weld Overlay Exams Until March 2001 or Until Completion of NRC Staff Review & Approval of Proposed Generic Rept,Whichever Comes First ML20195E3451999-06-0707 June 1999 Forwards 3.5 Inch Computer Diskette Containing Revised File Format for Annual Dose Rept for 1998,per 990520 Telcon Request from Nrc.Each Station Data Is Preceded by Header Record,Which Provides Info Necessary to Identify Data ML20195D6351999-06-0404 June 1999 Notifies NRC of Actions That Has Been Taken in Accordance with 10CFR26, Fitness for Duty Programs ML20207G2571999-06-0303 June 1999 Informs That Effective 990328,NRC Ofc of NRR Underwent Reorganization.Within Framework of Reorganization,Division of Licensing Project Management Created ML20195B2301999-05-19019 May 1999 Requests Approval of Proposed Changes to QA Topical Rept CE-1-A,rev 66a.Attachment a Describes Changes,Reason for Change & Basis for Concluding That Revised QAP Incorporating Proposed Changes Continues to Satisfy 10CFR50AppB ML20206Q3111999-05-18018 May 1999 Final Response to FOIA Request for Documents.Forwards App a Records Being Released in Entirety ML20206P2431999-05-13013 May 1999 Forwards Insp Rept 50-010/99-09 on 990325-0506.Two Violations of NRC Requirements Occurred & Being Treated as non-cited Violations Consistent with App C of Enforcement Policy ML20206F5381999-04-30030 April 1999 Forwards Magnetic Tape Containing Annual Dose Repts for 1998 for Braidwood,Byron,Dresden,Lasalle County,Quad Cities & Zion Nuclear Power Stations,Per 10CFR20.2206(c).Without Magnetic Tape ML20206B1501999-04-22022 April 1999 Forwards 1998 Occupational Radiation Exposure for Dresden Nuclear Power Station,Units 1,2 & 3. Rept Was Revised to Rept Only Individual Radiation Exposures Greater than 100 Mrem ML20206B2471999-04-20020 April 1999 Informs That SE Kuczynski Has Been Transferred to Position No Longer Requiring SRO License.Cancel License SOP-31030-1, Effective 990412 ML20205K5521999-04-0202 April 1999 Forwards Partially Withheld Security Insp Repts 50-010/99-07,50-237/99-07 & 50-249/99-07 on 990308-12.Two non-cited Violations Identified Involving Failure of Security Personnel to Implement Required Measures ML20205K5841999-03-31031 March 1999 Submits Rept on Status of Decommissioning Funding for Reactors Owned by Comm Ed.Attachment 1 Contains Amount of Decommissioning Funds Estimated to Be Required Pursuant to 10CFR50.75(b) & (C) ML20196K7001999-03-31031 March 1999 Forwards Dresden Nuclear Power Station,Units 1,2 & 3 Radioactive Effluent Release Rept,Jan-Dec 1998. ODCM Was Submitted by Ltr in Accordance with Dresden TS 6.9.A.4 of Dresden Tech Specs Section 6.14.A.3 ML20205D7231999-03-26026 March 1999 Informs That Region III Emergency Preparedness Inspector Will Be Provided Copy of Comed Exercise Manual for 990526 Annual Exercise at DNPS ML20205B4241999-03-23023 March 1999 Provides Results of drive-in Drill Conducted on 990208,as Well as Augmentation Phone Drills Conducted Since 981015,as Committed to in Util ML20207L7141999-03-0808 March 1999 Discusses Transmitting Changes Identified as Rev 59 to Security Plan for Dresden Nuclear Power Station,Units 1,2 & 3.Staff Determined That No NRC Approval Required in Accordance with 10CFR50.54(p) ML20207D6831999-03-0101 March 1999 Forwards fitness-for-duty Program Performance Data for Each Comed Nuclear Power Station & Corporate Support Employees for Six Month Period Ending 981231,per 10CFR26.71(d) ML20207E0931999-02-26026 February 1999 Informs That Region III EP Inspectors Will Be Provided One Copy of Exercise Evaluation Objectives for 990526 Annual Exercise at Dresden Station as Enclosure to Ltr for Review. Proprietary Encl Withheld ML20203F2541999-02-10010 February 1999 Informs That Beginning 990216,DE Hills Will Be Chief of Operations Branch Which Includes Operator Licensing Function ML20203G3631999-02-10010 February 1999 Forwards Insp Rept 50-010/99-02 on 981218-990129.No Violations Noted.During Insp,Activities in Area of Facility Mgt & Control,Decommissioning Support Activities & Radiological Safety Were Examined ML20203C7001999-02-0202 February 1999 Informs That Mhb Technical Associates No Longer Wishes to Receive Us Region III Docket Info Re Comed Nuclear Facilities.Please Remove Following Listing from Service List ML20202G0621999-01-25025 January 1999 Forwards 1998 Revs to Commitments Rept Made in Docketed Correspondence for Dresden Nuclear Power Station ML20199F3291999-01-14014 January 1999 Ack Receipt of Ltr Dtd 981230,transmitting Changes Identified as Rev 59 to Plant Security Plan,Submitted Under Provisions of 10CFR50.54(p) ML20199E0201999-01-12012 January 1999 Forwards Change to Bases of Dnps,Unit 1 TS Section 3.10, Fuel Handling & Storage. Change Eliminates Reference to Initiation of Generating Station EP Action That Is Incorrect & Not Part of Reason for Min FSP Water Level TS ML20199C8851999-01-11011 January 1999 Forwards Monthly Operating Repts for Dec 1998 for Dnps,Units 1,2 & 3,as Required by TS 6.9.A.5.Year-to-date Generator Hours for Unit 2 for Oct 1998 & Nov 1998 Corrected in Rept ML20206P7411999-01-0707 January 1999 Informs of Delay in Implementation of Strategic Reform Initiative Action Steps.Util Mgt Now Preceeding to Implement Succession Planning Steps for Corporate Ofc & Expects Completion of Action Steps 2 & 3 by 990128 ML20198N7691998-12-30030 December 1998 Forwards Rev 59 to Security Plan for Dresden Nuclear Power Station,In Accordance with 10CFR50.4(b)(4).Rev Withheld ML20198A2531998-12-10010 December 1998 Ack Receipt of Which Transmitted Changes Identified as Rev 57 to Plant Security Plan,Per 10CFR50.54(p).No NRC Approval Is Required ML20198A2511998-12-10010 December 1998 Ack Receipt of ,Which Transmitted Changes Identified as Rev 58 to Plant Security Plan,Per 10CFR50.54(p).No NRC Approval Is Required ML20196E2371998-11-27027 November 1998 Discusses Licensee ,Requesting That Agreement in Be Changed to Reflect Latest NRC Conditions Requiring Licensees to Notify NRC of Transfer of Assets to Affiliates Imposed in Connection with Approval of Transfer ML20196B5871998-11-20020 November 1998 Requests That Svc List for All NRC Correspondence Re Any of Six Comed Nuclear Stations Be Modified Per Attached List.All Other Names Previously Listed Should Be Removed ML20196A4121998-11-19019 November 1998 Forwards Safety Evaluation Accepting Proposed Changes to QA TR CE-1-A,Rev 66,by ,As Modified by Ltrs & 1027.Proposed QA Tr,Rev 66 Continues to Comply with Criteria of 10CFR50,App B ML20195J4271998-11-13013 November 1998 Forwards Insp Repts 50-010/98-18,50-237/98-27 & 50-249/98-27 on 981013-16 & Notice of Violation.Mgt Activities Were Focused Toward Maintaining Effective Security Program ML20195E6451998-11-12012 November 1998 Provides Results of drive-in Drill Conducted on 981007,as Well as Augmentation Phone Drill Conducted on 980917 ML20195F3461998-11-10010 November 1998 Forwards Rev 58 of DNPS Security Plan,Including Listed Changes,Iaw 10CFR50.4(b)(4).Encl Withheld Ref 10CFR73.21 ML20155D2701998-10-27027 October 1998 Forwards Changed Pages from 980423 Submittal Providing Addl Info Marked with Revision Bars & Revised Pages to QA Topical Rept Section 18,for Review ML20154P9051998-10-20020 October 1998 Ack Receipt of 980821 Submittal,Per 10CFR50.54(a),requesting Review & Approval of Proposed Changes That Reduce Commitments in QA TR,CE-1-A.Util Should Refrain from Implementing Subj Changes Until Formal Notification Given 1999-09-30
[Table view] Category:INCOMING CORRESPONDENCE
MONTHYEARML20217H4661999-10-18018 October 1999 Forwards Changes to EPIPs IAW 10CFR50.54(q) & 10CFR50,App E, Section V.Details of Changes Encl ML20216J8241999-09-30030 September 1999 Notifies of Removal of NRC Headquarters & Region III Offices from Controlled Copy Distribution of Certain CE Documents. Specific Documents,Associated Controlled Copy Numbers & NRC Location Affected Are Shown on Attachment to Ltr ML20211G1221999-08-27027 August 1999 Forwards fitness-for-duty Program Performance Data for Each of Comm Ed Nuclear Power Stations & Corporate Support Employees within Scope of Rule for six-month Period Ending 990630,IAW 10CFR26.71(d) ML20210N5651999-08-0606 August 1999 Forwards Rev 8 to Nuclear Generating Stations Emergency Plan, for Plants.With Summary of Changes ML20210M9131999-08-0202 August 1999 Forwards Response to NRC AL 99-02, Operating Reactor Licensing Action Estimates, for Fys 2000 & 2001 for Comed ML20210D2961999-07-20020 July 1999 Forwards Corrected Info for DNPS Unit 3 MOR for June 1999. Year-to Date Forced Outage Hours Should Have Read 70 Hours Instead of 0 on Page 8.Error Also Affected Cumulative Forced Outage Hours Which Should Have Been 24,761 ML20196J9131999-07-0101 July 1999 Submits Status of Nuclear Property Insurance Currently Maintained for Braidwood,Byron,Dresden,Lasalle County,Quad Cities & Zion Nuclear Power Stations,Per 10CFR50.54(w)(3) ML20196J9061999-07-0101 July 1999 Provides Evidence That Util Maintains Guarantee of Payment of Deferred Premiums in Amount of $10 Million for Each of Thirteen Reactors,Per 10CFR140.21 ML20209B8241999-06-30030 June 1999 Forwards Five 3.5 Inch Computer Diskettes Containing Revised Annual Dose Repts for 1994 Through 1998 for Individuals Receiving Neutron Dose Not Previously Included in Reported Total Effective Dose Equivalent Values.Without Diskettes ML20195E3451999-06-0707 June 1999 Forwards 3.5 Inch Computer Diskette Containing Revised File Format for Annual Dose Rept for 1998,per 990520 Telcon Request from Nrc.Each Station Data Is Preceded by Header Record,Which Provides Info Necessary to Identify Data ML20195D6351999-06-0404 June 1999 Notifies NRC of Actions That Has Been Taken in Accordance with 10CFR26, Fitness for Duty Programs ML20195B2301999-05-19019 May 1999 Requests Approval of Proposed Changes to QA Topical Rept CE-1-A,rev 66a.Attachment a Describes Changes,Reason for Change & Basis for Concluding That Revised QAP Incorporating Proposed Changes Continues to Satisfy 10CFR50AppB ML20206F5381999-04-30030 April 1999 Forwards Magnetic Tape Containing Annual Dose Repts for 1998 for Braidwood,Byron,Dresden,Lasalle County,Quad Cities & Zion Nuclear Power Stations,Per 10CFR20.2206(c).Without Magnetic Tape ML20206B1501999-04-22022 April 1999 Forwards 1998 Occupational Radiation Exposure for Dresden Nuclear Power Station,Units 1,2 & 3. Rept Was Revised to Rept Only Individual Radiation Exposures Greater than 100 Mrem ML20206B2471999-04-20020 April 1999 Informs That SE Kuczynski Has Been Transferred to Position No Longer Requiring SRO License.Cancel License SOP-31030-1, Effective 990412 ML20205K5841999-03-31031 March 1999 Submits Rept on Status of Decommissioning Funding for Reactors Owned by Comm Ed.Attachment 1 Contains Amount of Decommissioning Funds Estimated to Be Required Pursuant to 10CFR50.75(b) & (C) ML20196K7001999-03-31031 March 1999 Forwards Dresden Nuclear Power Station,Units 1,2 & 3 Radioactive Effluent Release Rept,Jan-Dec 1998. ODCM Was Submitted by Ltr in Accordance with Dresden TS 6.9.A.4 of Dresden Tech Specs Section 6.14.A.3 ML20205D7231999-03-26026 March 1999 Informs That Region III Emergency Preparedness Inspector Will Be Provided Copy of Comed Exercise Manual for 990526 Annual Exercise at DNPS ML20205B4241999-03-23023 March 1999 Provides Results of drive-in Drill Conducted on 990208,as Well as Augmentation Phone Drills Conducted Since 981015,as Committed to in Util ML20207D6831999-03-0101 March 1999 Forwards fitness-for-duty Program Performance Data for Each Comed Nuclear Power Station & Corporate Support Employees for Six Month Period Ending 981231,per 10CFR26.71(d) ML20207E0931999-02-26026 February 1999 Informs That Region III EP Inspectors Will Be Provided One Copy of Exercise Evaluation Objectives for 990526 Annual Exercise at Dresden Station as Enclosure to Ltr for Review. Proprietary Encl Withheld ML20203C7001999-02-0202 February 1999 Informs That Mhb Technical Associates No Longer Wishes to Receive Us Region III Docket Info Re Comed Nuclear Facilities.Please Remove Following Listing from Service List ML20202G0621999-01-25025 January 1999 Forwards 1998 Revs to Commitments Rept Made in Docketed Correspondence for Dresden Nuclear Power Station ML20199E0201999-01-12012 January 1999 Forwards Change to Bases of Dnps,Unit 1 TS Section 3.10, Fuel Handling & Storage. Change Eliminates Reference to Initiation of Generating Station EP Action That Is Incorrect & Not Part of Reason for Min FSP Water Level TS ML20199C8851999-01-11011 January 1999 Forwards Monthly Operating Repts for Dec 1998 for Dnps,Units 1,2 & 3,as Required by TS 6.9.A.5.Year-to-date Generator Hours for Unit 2 for Oct 1998 & Nov 1998 Corrected in Rept ML20206P7411999-01-0707 January 1999 Informs of Delay in Implementation of Strategic Reform Initiative Action Steps.Util Mgt Now Preceeding to Implement Succession Planning Steps for Corporate Ofc & Expects Completion of Action Steps 2 & 3 by 990128 ML20198N7691998-12-30030 December 1998 Forwards Rev 59 to Security Plan for Dresden Nuclear Power Station,In Accordance with 10CFR50.4(b)(4).Rev Withheld ML20196B5871998-11-20020 November 1998 Requests That Svc List for All NRC Correspondence Re Any of Six Comed Nuclear Stations Be Modified Per Attached List.All Other Names Previously Listed Should Be Removed ML20195E6451998-11-12012 November 1998 Provides Results of drive-in Drill Conducted on 981007,as Well as Augmentation Phone Drill Conducted on 980917 ML20195F3461998-11-10010 November 1998 Forwards Rev 58 of DNPS Security Plan,Including Listed Changes,Iaw 10CFR50.4(b)(4).Encl Withheld Ref 10CFR73.21 ML20155D2701998-10-27027 October 1998 Forwards Changed Pages from 980423 Submittal Providing Addl Info Marked with Revision Bars & Revised Pages to QA Topical Rept Section 18,for Review ML20154M4291998-10-15015 October 1998 Forwards 1998 Third Quarter 10CFR50.59 Rept of Completed Changes,Tests & Experiments.Completed SEs Compared to Previous Quarterly Repts as Docketed ML20154J4951998-10-0707 October 1998 Forwards Revised Security Plans for CE Listed Nuclear Power Stations,Per 10CFR50.4(b)(4).Changes Do Not Decrease Effectiveness of Station Security Plans.Encl Withheld ML20151Y5101998-09-11011 September 1998 Provides Results of drive-in-drill Conducted on 980804 & Augmentation Phone Drills Conducted Between 980601 & 0831 ML20151Y2931998-09-0909 September 1998 Notifies NRC of Results of Feasiblity Study of Seismically Qualified or Verified Path to Obtain Water from Ultimate Heat Sink & Deliver It to Shell of Isolation Condenser for Each Unit ML20238F7571998-08-28028 August 1998 Forwards fitness-for-duty Program Performance Data for Each of Util Nuclear Power Stations for Six Month Period Ending 980630 ML20237D9771998-08-21021 August 1998 Forwards Proposed Changes to Quality Assurance Topical Rept (QATR) CE-1-A,rev 66,modifying Ref Submittal & Clarifying Certain Changes to QATR Proposed in Util .Page A-1, 6 of 6 of Incoming Submittal Not Included ML20237A8611998-08-0707 August 1998 Requests Approval of Enclosed Qualified Unit 1 Supervisor Initial & Continuing Training Program, Which Ensures That Qualifications of Personnel Are Commensurate W/Tasks to Be Performed & Conditions Requiring Response ML20237A8871998-08-0707 August 1998 Documents Completion of Util Action Items Discussed at 980529 Meeting W/Nrc.Updated Proposal to Consolidate Near Site Emergency Operations Facilities Into Single Central Emergency Operations Facility,Provided ML20236W1311998-07-27027 July 1998 Forwards Response to NRC Re Violations Noted in Insp Repts 50-010/98-15,50-237/98-18 & 50-249/98-18, Respectively.Encl Withheld ML20236T7241998-07-24024 July 1998 Forwards Revised Epips,Including CEPIP-2000 Series Table of Contents & Rev 7 to CEPIP-2121-01, Augmentation Caller Instructions ML20236R2531998-07-16016 July 1998 Summarizes Results of drive-in Drill as Well as Preceeding call-in Drills Conducted Between Each drive-in Drill,As Committed to in 980326 Meeting Between Util & NRC ML20236F8041998-06-29029 June 1998 Forwards Rev 0 to Defueled SAR Dresden Nuclear Power Station Unit 1 Commonwealth Edison Co, Per Requirements of 10CFR50.71(e)(4).Decommissioning Program Plan Is Being Reformatted & Revised Into Defueled SAR SVP-98-170, Advises That AL Misak,License SOP-30832-1,is No Longer Required to Maintain Operator License1998-05-0101 May 1998 Advises That AL Misak,License SOP-30832-1,is No Longer Required to Maintain Operator License ML20247B6521998-04-30030 April 1998 Forwards 1997 Repts for Braidwood,Byron,Dresden,Lasalle,Quad Cities & Zion Nuclear Power Stations.Repts Being Submitted Electronically on Magnetic Tape.W/O Encl ML20217G8841998-04-23023 April 1998 Forwards Proposed Changes to QATR CE 1-A,rev 66.Change Constitutes Major Programmatic Rev to Onsite & Offsite Review Processes as Presently Described in Rept ML20246Q1391998-04-20020 April 1998 Provides Response to Violations Noted in Insp Repts 50-010/98-08,50-237/98-08 & 50-249/98-08.Corrective Actions: Described in Attachment Which Contains Safeguards Matl.Encl Withheld ML20217N3461998-03-31031 March 1998 Provides Basis for Plant Conclusion That Dam Failure Coincident W/Loca Is Beyond Design Basis of Dresden,Units 2 & 3.Licensing Amend Is Not Necessary & Clarifications to UFSAR May Be Made Through Provisions of 10CFR50.59 ML20216H4041998-03-13013 March 1998 Forwards Revs to Byron,Dresden,Lasalle & Zion Station OCDM, Current as of 971231,ODCM Manual & Summary of Changes Included ML20203L2911998-02-27027 February 1998 Provides Revised Schedule for Hazardous Matl Response Drill Described in 971121 Response to Insp Repts 50-010/97-13,50-237/97-13,50-249/97-13 & NOV 1999-09-30
[Table view] Category:UTILITY TO NRC
MONTHYEARML20059F0311990-08-27027 August 1990 Provides Schedule for Completion of Installation of Mods to Plants Reactor Water Level Instrumentation,Per Generic Ltr 84-23.Penetrations Will Be Installed During Outage 13 for Dresden & During Outage 12 for Quad-Cities ML20055H7631990-07-25025 July 1990 Forwards Financial Info Re Decommissioning of Plants ML17202L2861990-07-0202 July 1990 Forwards Dresden II Upper Vessel Contract Variation Review, La Salle II Upper Vessel Fabrication Summary & Quad-Cities II Upper Vessel Fabrication Summary. ML20043D3231990-06-0101 June 1990 Forwards Rev 31 to Security Plan.Rev Withheld (Ref 10CFR73.21) ML20043C8181990-05-30030 May 1990 Forwards Rev 1 to Core Operating Limits Rept,Dresden Station Unit 2,Cycle 12. Rev Reflects MCPR Limit Adjustment for Cycle 12 Due to Number of Reused Channels,Per Discussion of Channel Bow Effects in BWRs in NRC Bulletin 90-002 ML17202G7741990-02-0505 February 1990 Forwards Core Operating Limits Rept,Dresden Station Unit 2,Cycle 12,Rev 0 & Core Operating Limits Rept,Dresden Station Unit 3,Cycle 12,Rev 0. Cycle 12 Startup Expected on 900210 ML19332D3011989-11-15015 November 1989 Provides Update Concerning Evaluation of long-term Improvements to Unit 2 & 3 Isolation Condenser Shell Side Clean Demineralized Water Supply Sys ML19324C2271989-11-0909 November 1989 Forwards Response to Regulatory Effectiveness Review Insp on 890731-0804.Response Withheld ML17285A8081989-10-18018 October 1989 Responds to Request for Info on Environ Qualification of Taped Electrical Splices.Scotch Tapes Allowed by Electrical Test Guide Included Scotch 33,23 & 70 ML20248D0881989-09-21021 September 1989 Forwards Rev 56 to QA Program Topical Rept CE-1-A ML19325C5601989-09-13013 September 1989 Forwards Response to Allegation RIII-87-A-0074 Re Employment Discrimination,Per Eg Greenman 890801 Ltr to C Reid ML20245H3771989-08-0909 August 1989 Forwards Listed Policies,Including Endorsements 24 & 25 to Nelia Policy NF-294,Endorsements 19 & 20 to Maelu Policy MF-128,Endorsements 36 & 37 to Nelia Policy NF-277 & Endorsements 29 & 30 to Maelu Policy MF-114 ML20246L8141989-07-0101 July 1989 Forwards Dresden Nuclear Power Station Monthly Operating Summary Rept for June 1987.Info Previously Submitted on Annual Basis Now Included in Monthly Summary Rept ML20245L6831989-06-29029 June 1989 Forwards Addl Info on Emergency Planning & Fuel Handling Accident,Per E Erickson & R Beck Request ML20245G2411989-06-19019 June 1989 Forwards Endorsements 55,28,205,179,55,37,117,100,108 & 97 to Nelia & Maelu Policies NF-227,MF-114,NF-43,MF-22,NF-253, MF-104,NF-187,MF-54,NF-201 & MF-64.respectively ML20247J1051989-05-17017 May 1989 Responds to Items from SALP 8 Board Repts 50-237/89-01 & 50-249/89-01 for Feb 1988 - Jan 1989.Plant Security Program Now Implements All Aspects of Reporting All Events Identified,Per App E & Section 5.7,to NRC within 1 H ML20246B9501989-04-28028 April 1989 Forwards Rev 55 to CE-1-A, QA Program for Nuclear Generating Stations. Rept Reflects Organizational Changes Resulting from Current Self Analysis Performed in Effort to Improve Effectiveness ML20245J2421989-04-25025 April 1989 Forwards Rev 27 to Security Plan.Rev Withheld (Ref 10CFR73.21) ML20247B6021989-04-13013 April 1989 Forwards Results of Util Investigation of Allegation RIII-88-A-0147 Re Fitness for Duty.Encl Withheld (Ref 10CFR2.790(a)(7)) ML20245A1521989-04-12012 April 1989 Forwards Monthly Performance Rept for Mar 1989.W/o Encl ML20244B5081989-04-10010 April 1989 Forwards Addl Info Re Accident Analysis & Protective Action Plans During Emergency Conditions ML20244A7421989-04-0303 April 1989 Responds to 890201 Telcon Request for Addl Info Re Item 2.2.1.3, Use of Info Handling Sys & Item 2.2.1.4, Mgt Control of Generic Ltr 83-28 ML20244D1101989-03-28028 March 1989 Forwards Corrected Radioactive Effluent Rept for Jul-Dec 1988 for Plant.Final Data for Sr-89,Sr-90,Fe-55,tritium & Gross Alpha Included in Rept ML20248D9741989-03-27027 March 1989 Forwards Response to Requests for Addl Info Re Emergency Plan,Tech Specs & Decommissioning Plan.Info on Emergency Plan Requirements Will Be Provided by 890410,per 890323 Discussion W/P Erickson ML20247B2791989-03-23023 March 1989 Forwards Endorsements 23,18,34,27,202,176,54,36,114,97,105 & 93 to Nelia Policies NF-294,MF-128,NF-277,MF-114,NF-43, MF-22,NF-253,MF-104,NF-187,MF-54,NF-201 & MF-64, Respectively ML20246P2311989-03-20020 March 1989 Forwards Endorsements 203 & 204 to Nelia Policy NF-43, Endorsements 177 & 178 to Maelu Policy MF-22,Endorsements 115 & 116 to Nelia Policy NF-187 & Endorsements 98 & 99 to Maelu Policy MF-54 ML20247G5311989-03-20020 March 1989 Forwards Overheads Used at 890301 Meeting W/Region III Personnel in Working Group Level to Discuss Dc Ground Policy & How It Applies to Facilities ML20235V2721989-03-0101 March 1989 Forwards Corrected Rev 54 to Topical Rept CE-1-A, QA Program for Nuclear Generating Stations, Incorporating Pages 1-38 & 1-44 ML20235V5921989-02-28028 February 1989 Informs That Response to 880707,0927 & 890107 Requests for Addl Info Re Emergency Plan,Tech Specs & Decommissioning Plan Will Be Submitted by 890327,per 890228 Telcon W/P Erickson ML20235U4251989-02-28028 February 1989 Forwards Rev 26 to Security Plan.Rev Withheld ML20247E7771989-02-24024 February 1989 Forwards Radwaste & Environ Monitoring,Annual Rept 1988 ML20235Y6321989-02-22022 February 1989 Forwards Occupational Radiation Exposure Portions of Plants Operating Repts for 1988,per Reg Guide 1.16 ML20235Y8731989-02-14014 February 1989 Forwards Occupational Radiation Exposures Rept for 1988,per Reg Guide 1.16 ML20235Y6481989-02-14014 February 1989 Forwards Occupational Radiation Exposure Rept for 1988,per Reg Guide 1.16 ML20235U3411989-02-13013 February 1989 Forwards Corrected Radioactive Effluent Rept for Jan-June 1988.Final Data for Sr-89,Sr-90,Fe-55,tritium & Gross Alpha Included ML20235Y6541989-02-0606 February 1989 Forwards Occupational Radiation Exposure Rept for 1988,per Reg Guide 1.16 ML20235Y8491989-02-0202 February 1989 Forwards Occupational Radiation Exposure Rept for 1988,per Reg Guide 1.16 ML20235Y8571989-02-0101 February 1989 Forwards Occupational Radiation Exposures for 1988,per Reg Guide 1.16 ML20235Y6401989-01-27027 January 1989 Forwards Occupational Radiation Exposures Rept for 1988,per Reg Guide 1.16 ML20206K1501988-11-21021 November 1988 Provides Addl Info Re Util Decommissioning Plan & Tech Specs Per NRC 880927 Request.Info Provided Discussed W/P Erickson of NRC on 881117 ML20205P9231988-11-0101 November 1988 Discusses Proposed 881116 Meeting Re Dcrdr Mods & Enhancements,Including Program Overview,Summary of Completed & on-schedule Human Engineering Discrepancy Corrections & More Detailed Discussion of Items ML20154N8291988-09-23023 September 1988 Forwards Rev 25 to Security Plan.Rev Outlines Declassification of Unit 1 Reactor Sphere,Core spray/post- Incident Room & Cribhouse.Rev Withheld (Ref 10CFR73.21) ML20154D2881988-09-0808 September 1988 Responds to NRC Bulletin 88-005 & Suppls 1 & 2 Re Piping Supplies,Inc & West Jersey Mfg Co Matls Complying W/Asme Code Requirements.Itemized List of Components Received Encl ML20205A7531988-09-0202 September 1988 Responds to 880707 Request for Addl Info Re Emergency Plan Requirements for Facility Fuel Storage.Response Re Worst Case Skin Doses Projected Onsite & Worst Case Fuel Rod Rupture Provided ML20207F7261988-08-16016 August 1988 Forwards Endorsements 198 & 199,110 & 111 & 101 & 102 to Nelia Policies NF-43,NF-187,NF-201,respectively & Endorsements 172 & 173,93 & 94 & 89 & 90 to Maelu Policies MF-22,MF-54 & MF-64,respectively ML20155D2241988-06-0202 June 1988 Forwards Response to NRC Re Violations Noted in Insp Repts 50-010/88-02,50-237/88-07 & 50-249/88-08. Corrective Actions Withheld ML20154L8391988-05-27027 May 1988 Forwards Rev 24 to Security Plan to Correct & Make Current Identification on Number of Vital Area Doors on Various Levels.Rev Withheld (Ref 10CFR73.21) ML20154L7711988-05-19019 May 1988 Forwards Endorsements 197 to Nelia Policy NF-43,171 to Maelu Policy MF-22,50 to Nelia Policy NF-253,32 to Maelu Policy MF-104,109 to Nelia Policy NF-187 & 92 to Maelu Policy MF-54 ML20153G6091988-04-29029 April 1988 Forwards Environ Rept of Current Decommissioning Status of Dresden 1 & Decommisioning Program Plan for Dresden Nuclear Power Station Unit 1. Fee Paid ML20151U6961988-04-25025 April 1988 Forwards Endorsements 195 & 196 to Nelia Policy NF-43, Endorsements 169 & 170 to Maelu Policy MF-22,Endorsements 99 & 100 to Nelia Policy NF-201 & Endorsements 86 & 87 to Maelu Policy MF-64 1990-08-27
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{{#Wiki_filter:- -
. . L Comm ulth Edison 3/
Ont First r.at Plaza. Chicago, Illinois *
* (a/
a Address aply to: Post Offics Gox 767
- Chicago, Illinois 60690 BBS Ltr. #311-75 Dresden Nuclear Power Station R. R. #1 Morris, Illinois 60430 May 16, 1975.
[p, jok')59
/?f' u ,
# C Mr. James G. Koppler, Regional Director '
e, b Directorate of Regulatory Operations-Region III ;{
t U. S. Nuclear Regulatory Commission }. g , < gi s # ]/
799 Roosevelt Road /\ .NM g g% g# Y Glen Ellyn, Illinois 60137 SUBJIIT: License DPR-19, Dresden Nuclear Power Station, Unit 2, Control Drive Innpection Renort
References:
'1 ) Letter from W. P. Worden to A. Giambusso dated March 13, 1973
- 2) GE trip report on inspection of uncoupled drives dated April 4, 1973
- 3) Letter from W. P. Worden to A. Giambusso dated May 8, 1973
- 4) Letter from W. P. Worden to A. Giambusso dated Jt$1y 17,1973
- 5) Letter from B. B. Stephenson to J. P. O' Leary dated March 21,
,'. 1974 '
- 6) GE trip report on inspection of uncoupled drive, B-11, dated June 21, 1974
- 7) Letter from B. B. Stephenson to J. G. Keppler dated August 30, 1974
- 8) Letter from B. B. Stephenson to J. P. O' Leary dated June 24, ,
1974
- 9) GE trip report on inspection of uncoupled drives L-9 and K-11 dated Staptember 17, 1974
- 10) Letter from B. B. Stephenson to J. G. Keppler dated August 9, 1974
- 11) Letter from B. B. Stephenson to J. G. Keppler dated October 31, 1974
- 12) Letter frcm B. B. Stephenson to J. G. Keppler dated November 12, 1974 letter #807-74
- 13) Letter from B. B. Stephenson to J. G. Keppler dated November 12, 1974 Letter #812-74 BBR9b8%'d888bh f #y &
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- 4 i
Dear Mr. Keppler:
[ In the above referenced letters 8,10,11 &12, the station had committed-to sub-
- . mitting a letter detailing the mode of failure of four_ cont rol rod drives dating back from June 15, 1974_thru November 2, 1974. This letter will review,nin detail,~the' history of the control rod drive anomaly frem the first l: occurrence on February 19, 1973 thru November 2,1974, the results of-
- i. .each control drive inspection subsequent to removal from the reactor, failure of three CRD's to fully insert on a scram, and the overall. inspection of 137 control rod drives removed and overhauled during the winter 1974_ refueling
[
1 outage.
The first occurrence at Dresden of an apparent uncoupling of a control rod ' !
! drive (CRD) occurred on February 19, 1973 when three control rod drives ;
j (M(#20), .K-8 (s6560), L-11 (s91)) gave indication of an uncoupled condition when they were withdrawn during a startup of tha unit. -(Referred to in ref. 1, .
i 2, 3, and 4).
The three CRD's that were withdrawn to position"48"gave an overtravel alam
~~
annunciation when the overtravel check was performed. Both the four rod and a j full core display for the CRD's were lost, giving an indication of; an apparent .
i' uncoupled condition. The drivec were successfully recoupled on-the first l attemot and uncoupling was never experienced again even though each drive ;
i was subjected to twenty-five uncoupling checks on February 20,:and an uncoupling check once per day for a period of one week and once'per. week thereafter until l their removal on March 30, 1973 f
l The results of the visual inspection of the three (3) drives and the conclusions j reached by General Electric (GE) representatives are-as 'follows:
1 1. CRD K-8 (Flange No. 6560) y o
! This CRD had a measured overall length of 174-1/8 in; bas with the inner i filter installed and _173-3/8 inches without the filter. Adding thef l incremental length to account for a properly seated filter to the latter.
- measurement results in a corrected overall length of approximately.173--
7/6 inches which is within the allowable tolerance range for this .
{
measurement when the filter is properly seated. The= filter removal tool' ,
was engaged in the filter. Prior to any removal
- attempt,.the-filter was l' detemined .to have approximately 1/2 to' 3/4_ inch ' axial' movement. - In-addition, when remov 1 was attempted by 90*> rotation of'the tool',;no'.
l _ .
- spring tension was felt against the stop piston connector flats as'.it should' 7
have been. Removal was then achieved by simply withdrawing the filter-
{' removal tool until the filter was removed.' Close. visual ey = h tion
? (use of the eye piece) of the filter assembly was' performed atla distance of.
! -one foot through a plexiglass shield. .The-retainer spring at the base of the filter was distorted. The spring surfaces which mate with.the flats on the stop piston connector.were deflected up and out into the filter. .
This filter is considered.to have been disconnected from'theLatop piston? j i connector pricr.to removal identified above, i .
I: The damaged spring indicates that the filter could have_beenLimproperly, l installed prior to installation in the reactor. .)
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~2. CRD B-6 (Flans;c No. 20)
The second CRD inspected had an overall measured length of 173-3/4 inches, which also exceeds the specified dimension of 173 406 1 031. However, this filter was tight (approximately 1/8 inch axial movement) and was censidered firmly attached to the stop piston connector. The filter was rotated 90* and removed from the index tube, Observation of this filter also revealed a slightly bent retainer spring. Although it was concluded that this filter was properly attached at the time of its removal, the damaged spring indicates that the filter could have been improperly installed prior to installation in the reactor.
3 CRD L-11 (F3ance No. 91) P The third CRD inspected had an overall measured length of 173-{ inch'es.
The filter was tight (approximately 1/8 inch axial movement)-and firmly attached. The filter was rotated 90* and removed from the index tube.
The filter retainer spring was not damaged on this CRD. ,
e The conclusions from the initial inspection are summeized as follows:
1., Review of the engineering evaluation of the new CRD inner filter design reveals that damage occurred during testing to a retainer spring similar to that observed en the subject CRD's. This damagc occurred when the filter was installed without utilizing a rotating technique simul-- ,
taneously with inserting the filter. This motion centers the spring on the connector and prevents flush contact of the spring and flat top of the connector.
- 2. Two (2) CRD's contained inner filters with damaged retainer springs possibly caused by improper installation, o
3 The inner filter of CRD Flange No. 656C was determined by measurement and orientation not to be coupled to the stop piston connector.
- 4. The uncoupled condition of Flange No. 656C could be a result of failure to lock the filter on the connector following installation.
5 A drive in the condition in which 656C was discovered (i.e., detached filter with bent spring preventing engagement of filter to connector) effectively had a "long" unecupling rod setting. This could produce an actual uncoupling incident as the drive withdrew to position "48". ~
If so, it is hard to explain the proper engagement of the filter the next time (the coupling test was repeated as the bent spring would continue to interfere.
- 6. It may be surmised, based on the coupling spring damage only, that drive #20 could have experienced a similar sequence. This is believed very unlikely, however, as some mechanism must be postulated to cause rotation of the filter to a locked position following the first.
uncouple alarm.
. +
- 7. Drivef91 gave no evidence that the filter had ever been detached, and
.there was no evidence in the drive to indicate an uncoupling event ever occurred.
O O The following is the sequence of events which would have had to occur in order to have an uncoupling.- This postulated sequence is based, mainly, on finding one filter disconnected from the stop piston in the above CRD inspection.
- 1. Filter seated on stop-piston but not rotated and locked.
- 2. Friction or. filtera p pulls filter off the stop-piston connector. -
3 As CRD approaches position '48"the filter jams on top of the stop-piston connector. .
- 4. The uncoupling rod lifts the coupling lock plus, uncoupling the CRD. The alam sounds.
5 On the second withdraw, the filter re-seats on the stop-piston correctly.
- 6. The filter either reins in place on the stop piston or, if it comes off,
- it never jams again.
- 7. Two of the filters return to the locked position and one filter comes off again (during the drive removal operation).
From the analysis at the time of the uncoupling indication and the continued investigation, it is G.E.'s conclusion that although unlikely, the most likely explanation was that a rod uncoupling did occur regarding drives #20 and #91.
The second occurrence of an apparent uncoupled CRD occurred on March 14, 1974 when control rod B-11, SN 7610, gave indication of an uncoupled condition.
when it was withdrawn following a routine 25 CRD scram test. (Referred'to '
in Ref. 5, 6, and 7). While CRD B-11 was in the process of withdrawing to.
position "48** a " rod overtravel" alarm annunicated and both the four rod'and full core displays for the red were lost. The drive was successfully recoupled on the first attempt and subsequent attempts to withdraw at position "48" verified that a positive coupling had been obtained. During the overtravel check time.
span, the drive was inserted and withdrawn in 6 notch increments. The reactivity changes were being monitored by the TIP system and it was verified that the blade followed the CRD. In addition to the uncoupling checks, the CRD was
~
scrammed three (3) times to_ test the possibility of recurrence. The drive was scrammed successfully two (2) times, however, after the third scrm, while withdrawing, the drive went.to overtravel. At this time friction test equipnent was set-up to detemine pressure drop across the drive which would indicate if the CRD had uncoupled. The test results showed that the blade was uncoupled but recoupled.when' the CRD was' moved past position "48._
~
Following these tests, the drive was' inserted to' position "00", electrically disamed and removed from service until June 10, 1974_when the drive was removed from the reactor.
- The results of the visual inspection of CRD B-11 and the conclusions reached by GE representatives are as follows: -
l l
The uncoupling rod was confimed 'to be properly seated against the-inner '
filter prior to installation of the measuring gage. The overall length -
I 4.
. (17 .406 1 031) w asur:d several times and de h ed to be 173.890 inch or approximately .5 inch longer than the maximum allowable overall dimension. The outer filter and the spud were then removed for decontamination.
l l
In an attempt to determine if the filter was inserted on the stop piston connector !
to any degree, a hooked shaped piece of weld wire was engaged in the filter l and an attempt was made to withdraw the filter. The filter moved freely with a minimum of force. Normal disassembly of the CRD continued with the resulting observations.
Inner Filter:
The inner filter wiper ring did not exhibit a 360' wear pattern (i.e., approximately 1/2 - 3/4 inches on circumference of ring was not sealing in bore of index tube). The land of the filter (i.e., outer . diameter) Just below the wiper ring and the outer filter diameter just above the ring exhibited a wear pattern which could be caused by misorienting (i.e., cocking) the filter in the bore of the index tube. One leg of the filter retaining spring was displaced inward approxinately 1/4 to 3/8 inches and spread out radially about 3/8 of an inch. Some raieed metal was observed on both legs of the spring.
No damage to the back side of the spring (i.e., damage which would be caused if the filter was pulled off stop piston connector) could be observed. The inner filter was very clean indicating that a large degree of bypass flow had
,, occurred.
Stop Piston: The stop piston connector was observed to have two (2) areas on the flat which exhibited signs of impact with the retainer spring (i.e.,
raised metal) and two (2) scored areas leading from these impact areas across the chamfer and down the connector outer diameter. There was no sign of distortion or raised metal on the lip of the connector head which would be indicative of the filter being removed from a properly engaged position on the atop piston connector.
Index Tube: There was a scored area in the bare of the lndex tube which started approximately one foot from the spud end and ran for approximately two feet.
This indication could have been caused by the misorientation of the inner filter.
In~ summary, ~CRD S/N 761C is considre d to have uncoupled as a result of detachment of the inner filter. This detachment is considered to have occurred as a result of improper assembly which damaged the filter retainer spring (i.e., spring re@ir techniques when used were net effective) or improper assembly which resulted from a failure to securely lock the filter after engagement on the stop piston connector. This conclusion has been reached as a result of the following:
1)~~ No evidence of damage was observed which would have resulted if a properly
- locked filter had been pulled off the stop piston connector.
- 2) No vehicle for rotating a properly locked filter is known to exist.
Observations of index tubes following testing at San Jose and in the field have to date always identified a singular wear pattern caused by the collet fingers which verifies that no random rotation of the index tube has occurred.
6 1- 1 CONCLUSIONS -l i
i .
1); CRD'S$ 761C did inadvertently uncouple as a resul f dstachm:nt of ths- l j inner filter.
i
- 2) Detachment of the inner filter is considered to have been caused by improper
> assembly of this filter during the spring 1972 outage for filter modification. ;
l The third occurrence of an apparent uncoupled CRD occurred on June 15, 1975 when control i rod L-9, SN 620 C, gave indication of an uncoupled condition when it was witndrawn I during the startup sequence of the unit. (Referred to in Ref. 8 and 9). While CRD
! L-9 was in the process of being withdrawn from position "14" to "48", a " rod overtravel"
' alam annunciated and both the four rod and full core displays for the rod went blank.
{ h e initial action taken was to attempt to recouple by inserting and withdrawing the i rod three (3) times. On each series of insert and withdraw, the rod went into overtravel
! on the coupling check.
i
}
The corrective action taken was to insert the rod to position "00", electrically i
disam it and remove from service until August 26, 1974 when the drive was removed
- . from reactor.
- e
- The results of the visual inspection of CED L-9 and the conclusions reached by GE l rspresentatives and CECO personnel are as follows
1 j Immediately after removal of the CRD from the reactor vessel, a visual inspection of the spud end was perfomed. It was noted that the uncoupling rod was distorted (bent)
! cbove the point at which it is supported in the spud. In addition, an attempt was I
made to pull the uncoupling rod but it was found to be tight. This indicated that the uncoupling rod may also be distorted on the lower end which lies inside the index tube.
l On disassembly of the drive, it was noted that the inner filter was lodged in the bore-l cf the index tube, approximately 1.25 inches from the spud end. The wiper ring on the j inner filter was forced up and out of the groove by displacing the top lip of the wiper
! groove in a localized area. The wiper ring was wedged into the index tube such that l the filter had to be removed by force. Normal disassembly of the CRD was continued
{ with the resulting observations:
Inner Filters i
(
j The dimple at the base of the filter, which covers the stop piston connector and contacts
- the uncoupling rod, had been reversed (i.e., upset) by apparent contact with the
! uncoupling rod. The uncoupling rod had been distorted (bent) relative to its center-
- line both above and below the point at which it is supported in the spud. The bottom j cf the filter can was bulged outward apparently caused by contact of the dimple with j the uncoupling rod. Tne retainer spring was distorted in a manner similar to'that
! previously observed on other uncoupled CRD's. The filter mesh was slightly collapsed j (bulged) inward; howeve.', relative cleanliness of this filter could not be determined '
i cince it had been ultrasonically cleaned prior to inspection.
i
- Stop Piston
1
! The stop piston connector was observed to have no sign of damage to the 1e M af flats (i.e., surface which retains filter by contact with retainer spring). .;
J 1
"_____ ___.-_ , . _ _ _ _ _ _ _ _. _ ~ ~ J
Tha top or flat of th9 connector was observed to contain slight indications of contact with the iner spring and the previouf bserved scored area which progressed down the chamfor and onto the major diameter of the connector.
In summary, damage to the inner filter and uncoupling rod of CRD S/N 620C has not been observed on other C.Yfs. The probable cause of this condition is considered to be a result of the inner filter, once uncoupled, being jammed in the index tube on the chamfer below the threads (i.e., spud coupling). In this position the full weight of the CR plus momentum of the translating assembly could be exerted on the inner filter.
Conclusions:
- 1) CRD SN 620C was determined to have been uncoupled when inspected and detachment is considered to have occurred as a result of contact with the uncoupling rod. This damage is considered to have occurred as a result of the free floating (i.e., detached filter) inner filter sticking at the top of the index tube bore and impacting on the uncoupling rod when scrammed.
The fourth occurrence of an apparent uncoupled CRD occurred on August 2,1974 when control rod K-11, S.N. 930, gave indication of an uncoupled condition when it was withdrawn during a unit power increase. (Referred to in Ref. 9 and 10).
While CRD K-11 was in the process of being withdrawn from position "42" to "48", a " rod overtravel" alarm annunciated and both the four rod and full core displays for the rod went blank.
The initial action taken was to attempt to recouple by inserting and withdrawing the rod five (5) times. On four series of inserts and withdrawals, the rod went into overtravel on the uncoupling check. The fifth attempt, however, was successful in getting the CRD coupled.
The corrective action taken vas to insert the rod to position "00", electrically disarm it and remove from service until August 26, 1974 when the drive was removed from the reactor.
The results of the visual inspection of CRD K-11 and the conclusions reached by GE representatives and CECO parsonnel are as follows:
During the removal phase of the CRD on August 26, it was noted that the uncoupling rod was extended above the spud fingers about 1 inches which is approximately inch longer than is designed.
_ VISUAL INSPECTION.
The uncoupling rod was determined to be properly seated against the inner filter prior to installation of the gage which measures overall CRD length.
The measurement was taken and found to exceed drawing requirements (i.e.,
173.406 1 031 inches) by approximately 5/8 inches (i.e.,- 174.181). The outer filter and spud were then removed and placed in the ultrasonic cleaner.
The h er filter was determined to be uncoupled from the stop piston during its removal. The filter was also observed to be relatively clean and free of the normal deposit of various contaminants.
I
-~
INNER FILTER
.J ^
*No unusual wear pattern was_ observed on tha land of the filter nzar the w iper ring. The filter retaining spring was deflected outward-
'~
(radially) and displaced inward similar to that described in the referenced report No. 6.- A slight bulging l(radially inward) ~of the filter mesh (i.e., wire cloth) was observed.-
STOP PISTON The ston piston connector was observed to have no sign of damage to.
locking flats and, in general, to have_ the same indications observed on S/hi 620C and all other stop pistons removed from CRIls which have experienced inadvertent uncouplings.
In sumary, CRD SN930 is considered to have been in a similar condition '
to that of other uncoupled CRDs previously observed.
CONCLUSION
. 1) CRD SN 930 was determined to have been uncoupled when inspected and
. detachment was considered to have occurred as a result of. improper -
assembly.
The fifth occurrence of an apparent uncoupled CRD occurred.on October 23,.1974-when control rod P-12, SN 54, gave indication of an uncoupled condition when it was withdrawn following a scram test.
i While CRD P-12 was being withdrawn from position "00" to "48", a" rod overtravel" 4 alarm annunciated and both the four rod and full. core displays for the rod went blank. /
The initial action taken was to immediately_ insert the CRD to position "00",
.el_ectrically disarm it and remove from service until January 29, 1975 when'the
-drive was removed from the reactor.
~
The results of the visual inspection of CRD P-12 and the conclusions reached by GE representatives, who were contracted to overhaul one hundred-thirty _
~
seven (137) CRUS, and CECO personnel are' as followst L'
During the removal phase of the CRD, it was noted that the uncoupling rod was extended above the spud fingers about 1-) inches. This distance
_. should normally be about 3/4 inch.
VISUAL INSPECTION' '
i' .. ,
Upon disassembiy, it was found'that the inner filter was uncoupled from_the-
- stop piston. The filter could be moved by hand. The filter was also r- ' observed to have a minimal amount of crud deposit.
INNER FILTER No unusual wear pattern was observed on-the lan_d 'of the filter near-the wiper.
ring. The filter retaining spring was in satisfactory condition' showing no signs of the distortion noted in previous uncoupled CRD.'s.
. STOP PISTON The. stop piston connector'was observed to' have ~a longitudinal 'acratch running x
t -
downIthe chamfer. its scratch indicates that ec: t was made with'ths
, rathintr springs but the filter was no.t properly installed. i CONCLUSION CRD SN 54 was determined to have been uncoupled when inspected and detachment
' i is considered to have occurred as a result of improper assembly.
The sixth and final occurrence of an apparent uncoupled CRD occurred on
. November 2,1974 when controlrod N-10, SN 275, gave an indication of an
- uncoupled condition when it was withdrawn following a unit scram.
i Wile CRD N-10 was being withdrawn from position "00 to ."48",' a " rod.
1 - overtravel" alarm annunciated and both the four rod and full core displays for the rod went blank.
i The initial action taken was to inmediately insert the CRD to position "00",
electrically disarm it and remove from service until January 31, 1975 when the drive was removed from the reactor.
- 7. The results of the visual inspection of CRD N-10 and the conclusions reached by GE representatives, who were contracted to overhaul 137 CRD's,and CECO personnel are as follows:
- During the removal phase of the CRD, it was noted that the uncoupling rod wasextendedabovethespudfingerabout1) inches._
7 VISUAL INSPECTION
. ; i Upon disassembly, it was found that the inner filter was uncoupled from.the . l
; stop piston. The filter could be moved by hand.- The filter was also observed j to have about inch of various contaminents contained in it .
INNER FILTER
! No unusual wear pattern, as stated in CRD P-12_ visual inspection, was observed'-
i on the land of the filter near the wiper ring. The filter retaining spring was distorted in the same manner as depicted in previous CRD-findings..
{
h STOP PISTON . ,
t As stated in the CRD P-12 uncoupling occurrence, the connector. was observed
- to have a longitudinal scratch running down the chamfer.
CONCLUSION ..'
I I
CRD.SN 275 was determined to have been uncoupled when inspected and detachment
! is considered to have occurred as-a result of improper assembly.
e To sunrearize the history of the station's uncoupling problem, all the' uncoupled-I drives experienced at Dresden have been concluded to be a result of retainer; ,
spring damage and/or. improper assembly techniques. No d,her problem areas ,
.were' uncovered which could have producedithis type of failure. The' CRIfs ..
c 4
. - *
- m. , , y w- e- # -,, -- - - ~ -,, ,+,-.e- a- p , - [ g- -, <. - .
.. which havs experOced uncoupling were from a grib of'8f drives rebuilt and 1 modified (changoIYFom a traveling filter to a st',aYionary one) in the field during the same pecied of time (spring 1972 refueling outage) by General Electric.
\
As a result of these findings, all remaining CRD's overhauled by GE in 1972 ;
were removed from the reactor during the winter 1974 refueling outage, inspected, n overhauled and reinstalled into the reactor. No other CRD's overhauled this cutage, other than those discussed in this report, exhibited unattached inner filters.
A total of one hundred and thirty seven drives were overhauled by General Electric personnel, who were trained at a special CRD simulator, as a result of previous failures of CRD's to go to position "00" on a scram situation, drive pressure required to move the CRD greater than 250 psi, long. scram times or electrically disarmed CRDs due to an uncoupling indication.
- The general condition of the CRD's overhauled this outage was as follows:
- 1) Majority exhibited stop piston seal breakage.
- 2) Majority exhibited pitting of the nitrided surface on the piston tubes in a localized area. Six piston tubes were replaced due to severe pitting.
- 3) Minimm number exhibited drive piston seal damage.
Among the 137 CRD's overhauled, three of them were involved in an occurrence on November 2, 1974 when they failed to fully insert on a scram.
} On November 2,1974 unit 2 scramed due to low water level in the reactor. k Subsequent to the scram, it was noted that CRD F-6 stopped at position "04" I and CRD's H-9 and G-8 at position "06". These drives were then inserted one- {-
ata a-time to position "00".
The apparent cause of this problem relates to two factors:
1
- 1) The gradual deterioration of control rod stop piston seals.
- 2) 'The decreased time for the scram discharge volume high level alarm to annunciate.
s These factors relate directly to the cause of this problem, in that, due to the degradation of the control rod seals and subsequent increased leakage, the scram discharge volume rapidly increases, resulting in pressurizing the system.
With insufficient scram discharge volume, a high back pressure is developed relative to CRD inserted with the rods with the slowest scram times stopping at positions greater than "00" or "02". -
To minimize the recurrence of this problem, the station's corrective action was to overhaul the CRds whose perfomance indicated seal damage and also increase the scram discharge volume to handle the regular drive displaced water plus the -
high drive leakage-due to seal wear. Note: ' The visual inspection of the three
{ drives involved in' this occurrence revealed stop piston. seal breakage resulting in increased 1cakage and slower scram times. .
q"B.B.Stephenson Superintendent =
Dresden Nuclear Power Station.
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