ML101550537
| ML101550537 | |
| Person / Time | |
|---|---|
| Site: | Three Mile Island  |
| Issue date: | 05/26/2010 |
| From: | Exelon Corp |
| To: | NRC Region 1 |
| References | |
| FOIA/PA-2010-0118 | |
| Download: ML101550537 (14) | |
Text
Originator: CATHERINEý,G HARDEE Supv Contacted: Russ Green, C. Wend, R Barley ;n Condition
Description:
o requireme CX .
ECR TM 06-00816, Rev 1, Containment*Structuir4" Opening, RB purge was(not aintained to induce air flow into containment after the RB liner plate was removed. The RB liner plate was removed to provide a construction opening to support OTSG replacement during TIRl8. Additionally,(a the alt -,eatv-eme as Tes, prescribed for cases when the RB purge was unavailable apparen!f1f-06treln' Immediate actions taken:
Inm ediate c. _nso:
1.) RB<Eurge~restored.
2.) Operations StAgding Order issued to ensure appropriate control of RB purge and to ensure airflow into reactor building maintained or alternate control measures in place.
Recommended Actions:
Re'view issue witgard to failure to implement design requirements and lack of organizational sensitivity to potential release pathway. Identify and implement corrective actions Why did the condition happen?
si'ng-e poif 3o-f ontact--fbr all ventilation related activities was recommended by Ops durn--t-4ER review but dois not appear to have been implemented.
Referenc IR 994989 alerted station personnel to this problem on 11/18/09.
Operable Basis: .V Reportable Basis:
Reviewed by: BRADLEY A PARFITT 12/03/2009 09:44:02 CST Reviewer Comments:
Reviewed by Operations for operability and reportability. This issue has no impact on the ability to safely operate the plant, to achieve or maintain the plant in a safe shutdown condition, or to mitigate the effect of any accident condition. This is a process issue that does not identify an equipment deficiency that affects operability of any SSC. There are no operability or reportability concerns.
SOC Reviewed by: SUZANNE M SULLIVAN 12/09/2009 09:57:04 CST SOC Comments:
Followup to Ops to determine action. (SOC 12/04/09)
Design Engineering agreed to take the lead on the ACE. Close to ACE actions created. (REH 12/8/09) (SOC 12/09/09)
Reviewed by: RANDY E HESS 12/08/2009 10:00:25 CST Reviewer Comments:
it -!oo r
Issue discussed with Operations, Engineering, SGRP, and the airborne lead. Design Engineering agreed to RCE team lead the ACE with assistance and SGRP. ACE actions created. from -Operatiosn (REH 12/08/09)
.- -- LS-AA-125-1003 Revision 8 Extension 2: From 01/25/10 to 02/03/l0,.approved by the MRC on 01/20/10. See Attributes for approva<ldocument. P. Fn/0,1-/-0710.
Reopen and extension approved by Acting Plant Manage 01/11/10.
/
See Assignment Attributes for approval paperwork and/IR submittal for late request (IR 1014623). /
ACE reopened extended to 01/25/.1 0P MRC due dated extended bintil-02/08/10.
P. Fink 01/11/10.
Exelkn.
Apparent Cause Evaluation
Title:
Negative Pressure Not Maintained in the Reactor Building during High Contamination Work Condition eport #: 100081T-CFI Event Date/Event Time: 11/7/09 -11/21/09 Station/Unit(s): TMI-S1po......ig.....
e--Pat 'i-...
Sponsoring_ Man azer:jPat--B'l-e .- A 5-*6J "f.!fnK Investigator~s):-Michael Harty Condition Statement:
The reactor building purge exhaust system wa not service ._*_____
between- * ,per r//the quirements
/ of ECR if-t'itm TM 06-00816 "OTSG Replamment - Containment Strucmtrul Opening." flne respect to the outside environment in the reactor building while high contamination work continued. Without negative pressure, airborne contamination could be free to escape the building through the construction opening or equipment hatch instead of being directed through the purge exhaust system where it would be removed by the reactor building purge filtration system. Additionally, alternative measures prescribed .
for cases when the reactor building purge was unavailable were not applied.
Event-Des~cr__ption:
Background:
The scope of ECR TM 06-00816, was to provide the engineering for creating and restoring a temporary opening in the side of the containment building, above the Equipment Hatch, to facilitate ingress/egress of the steam generators as well as equipment and personnel. The ECR TM 06-00816 details the requirements for the various activities pre-outage while at power, outage activities while in cold shutdown, during refueling shutdown and while defueled. Included in these activities is aee g olzýrMIAh it-for containment building liner removal.
From the time that the liner was breached until the time it was restored, the plant was in Mode6,
- Defueled. In the de-fueled mode, there are no licensing requirements that require containment integrity or mandate the operation of the p~uirge system. TMI Technical Specifications only require the RB purge to be running when containment integrity is not required during the movement of irradiated fuel. Impact reviews were conducted with extensive documentation and determined that no procedures required revision for this ECR. As determined by impact reviews, the ECR did not take actions to modify any procedures in order to explicitly prevent the planned shutdown of the purge system.
Appendix I of 10 CFR 50.34a sets the limits on the amount of radiological material that can be released to the environment, and mandates the monitoring, calculation, and reporting of results to the NRC. TMI complies with these requirements through the Offsite Dose Calculation Manual (ODCM). In accordance with the ECR, radiation monitors (AMS4) were placed at the construction opening to support data collection for the ODCM.
lirig aees ~ existed within the reactor building with the Auxiliary and Fuel Handling Building Ventilation system on. This system draws air from the Reactor Building through the personnel hatch. So, even with the Reactor Building uur,ge'systemiof*.fere was a shght negative pressure in the building with respect to the outside environment.
Prior to approval of ECR 06-00816 the package was sent out for Interfacing Department Impact Reviews in accordance with the requirements of CC-AA-103, Configuration Change Control and CC-Page I of 12
~Exeion AA-102, Design Input and Configuration Change Impact Screening. The Impact Review phase of a project is used to identify the drawings, design bases, licensing documents, programs, procedures and training that are impacted, evaluate the technical adequacy of the proposed change, and initiate the revisions to the affected documents and programs. This Impact review phase is also used to provide comments on the implementation of the proposed change to address constructability concerns.
A2187706, ECR 06-00816 Remove/Restore Containment Structural Opening Evaluation #04 contains the Interfacing, Department Impact Review performed by Operations. Contained in this evaluation is the followin quest igQn, "There is a significant amount of coordination required with regard to operation of the Reactor Building purge and verification of plant mode prior to initiating various phases of the project. Who is responsible for coordination and what work documents incorporate verification of the plant modes?" Furthermore, the Operations review stated "I have identified no program changes, no changes to plant procedure, and no training "
These comments were addressed in the ECR section 3.19 - System operating requirements changed or added:
"During further interim conditions of the liner plate, to include removal -and reinstallation, the Reactor Building Purge and Vent System may be adjusted, for practical reasons, so as to minimize differential pressure across the liner plate .... as an aid to maintaining the optimal condition of a slight negative pressure on containment such that all effluent air is passing a monitored release site_,.a single point of contact with operations will be established to communicate with the Operations department regarding these developments:
0 Liner plate is first breached via cutting 0 Liner plate is removed
- Liner plate curtains are installed or removed
- Liner plate is placed back into the opening.
Any purge adjustments must be coordinated with the Operations through a single point of contact."
The ALARA Installation Review, page 6 of attachment 7 to the ECR shows the radiation protection department's comments. Control of airoorneon-Ctamnalyon was deemedn.essary... For the mitigation of airborne release it was recommended that "Negative ventil ation should be maintained b purge pier ]Exel-on ýprocedures'- and that *c.* ld be ob uldover the-oenln2 to mitigate effects of inclement weather or loss of RB purge.'
These comments were addressed in the ECR, section 1.2.1.2- Outage activities while in cold shutdown, refueling shutdown, or defueled:
h.) Control and Monitoring of Contamination "The Reactor Building purge will be maintained as required by Exelon procedures to induce airflow into) (Z containment"... "ifthereis a ventilation failure for any reason, RP may direct that any of the fol-lowing measures be taken until the purge is restored:
a.) Discontinue work activities with potential airborne contamination levels; b.) Close all openings to the outside environment, including the containment access opening (two (2) curtains, an inner and an outer, shall be provided covering the containment opening '
once the concrete and liner has been removed); and, Page 2 of 12
Exe,16n' c.) Provide and operate auxiliary purge HEPA units (as needed) to permit appropriate airborne contamination controls for hot particle work.
Outage work was planned for the inspection of purge supply and exhaust valves AH-V-1A and AH-V-1D as well as purge supply isolation valve AH-V-1C. Multi-step clearance #9500697 was written to support this work. Clearance step #2 includes. actions by the operations department to shut down the purge system and ensure the purge exhaust (AH-V-1A) and purge supply (AH-V-1D) valves are closed locally, resulting in the inability for air to enter or leave the reactor building through the purge system. The approver of the clearance consulted purge operating procedures and determined it was acceptable to remove the purge from service. He then checked with the Outage Control Center to see if it was an appropriate time to take the purge out so the clearance could go. into effect and the scheduled work could be completed. Operations followed procedure OP-TM-823-408, "RB Purge - Doors and/or Equipment Hatch Open" to remove the purge from service on 11/7/2009 and step #2 of the clearance was executed on 11/8/09. It remained active, with the purge sysstem off until it was suspended on 11/19/09 in order to lift all tags to allow the RB purge to be placed back in service.
A timeline of important events has been included as Attachment #1, Interviews were conducted with the following people to ascertain details of the situation:
- John Blair - Shift Operations Superintendent
- Bill Price - Clearance Approver
- Don Allison - Operations Services Manager 0 Laura Weber - ODCM Coordinator Causal Factors:
Apparent Cause #1 Compensatory measures included in ECR #06-00816 to prevent the-release of radiological material, in case of a ventilation failure were not installed until long after the liner had been removed. The hanging of the construction opening tarp was included as the second to last step of the SGT work package for the removal of the liner plate. While the final step, notifying TMI SGRP Ops that the containment purge system can be returned to normal service was completed on 11/11, the tarp was not installed until 11/19 (see items 1070 and 1080 in attachment #2).
An error precursor not recognized was unclear goals, roles, and responsibilities. The goal of installing the£ i to be able to close it while the liner was removed if purge system was lost. A clearer understanding of the curtain's purpose could have forced its installation immediately after the liner was removed, with the knowledge that the reactor building purge system was taken out of service A defense that failed to prevent this inappropriate action was planning and OOPS. The work package was written with the assumption that the purge system would be available, temporarily adjusted for the liner removal, and then placed back in service. When step 1080 was performed to notify SGRP Ops that Page 3 of 12
Exelkn the Containment Purge System can now be returned to normal service, OOPS would apply in that the service could NOT be returned to normal service due to a clearance.
Apparent Cause #2 Throughout the development of the ECR, operations, radiation protection, and engineering failed to coordinate the execution of the compensatory measures for any failure of the ventilation system.
While the reactor building purge was addressed several times in the ECR, the directions were to maintain it in accordance with the existing Exelon processes and procedures. While radiation protection may have assumed that this direction would keep the purge running the entire time, Exelon procedures allow the purge to be turned off.
The purge operating procedures were not changed with the assumption that Radiation Protection would.
execute compensatory measures prior to the planned tag out of the purge system. Per SGT work order, Radiation Protection was informed on 11/6 that the liner would be cut in 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />. Per procedure OP-TM-823-408-Ra-di*i -Pt-t-wfion was i-frmed on 11/7 that the re-actr b-ilding-purge-swystem was*--
taken out of service for maintenance. There were no actionis in place to drive radiation protectionto take the compensatory measures outlined in the ECR for when the construction opening existed.and- the cp.uxge System was ost."
An error precursor not recognized is assumptions and interpretation requirements. The assumption that Exelon procedures would keep the purge on throughout the work process was incorrect. The statement in the ECR stating "The reactor building purge will be maintained as required by Exelon procedures to induce airflow into containment" was interpreted to mean different things by the Operations and Radiation Protection departments.
A defense that failed to prevent this inappropriate action is an Exelon fundamental, maintaining a questioning attitude. Further questioning the comments included in the impact reviews could have uncovered flaws in the design implementation.
Pr'oblem:,Stat'ement,:,:, Cause(s),, rasissfo CausO Determination Compensatory measures Apparent The intent of the ECR was to'have the curtain in place as included to prevent the Management System a contingency. The order of the work completion could release of radiological have been stricter to ensure the curtain was in place material in case of a SPAC (Standards, immediately following the breach of the liner plate to ventilation failure were Policies, Admin Controls) ensure the opening could be coverad.
not installed until 8 days Not Strict Enough (5NS) after the liner had been removed.
Adequate measures not Apparent Comments provided during the impact review process by taken during the Inappropriate Action the Radiation Protection and Operations departments development of the ECR were not integrated. RP assumed that the operating to drive the execution of Communications - no procedures would keep the purge system on while compensatory measures. communication or not Operations assumed that RP would take compensatory timely (4NC) actions, preventing the need for interim procedural changes. The engineering outlined the compensatory measures to be taken without creating actions to drive their execution.
Page 4 of 12
Exelkn Cause befing addressed Exten~t of CondifionlReview Compensatory measures The extent of condition applies to the possibility of compensatory measures that are included to prevent the unable-to be taken ifthe RB purge is lost for any reason.
release of radiological material in case of a ventilation failure were The liner plate has been restored and the compensatory measures included in the not installed until 8 days ECR are no longer applicable. No further actions are required.
after the liner had been removed.
Adequate measures not The extent of condition applies to the possibility of compensatory measures not being taken during-the executed ifthe RB purge is lost for any reason.
development of the ECR to drive the execution of compensatory measures. The liner plate has been restored and the compensatory measures included in the ECR are no longer applicable. No further actions are required.
Caus6el beingadd'ressed" Ektent of.Cause Review.
Compensatory measures The extent of cause applies to ECR's that include compensatory measures in the included to prevent the event that a system that is assumed to be operating is lost or taken out of service. Any release of radiological work required to enact the contingencies must be completed prior to the time they material in case of a would be needed.
ventilation failure were not installed until 8. days after'the liner had been Action # 100819-08 has been created to identify the ECR's that include compensatory removed, measures and interim actions during the construction phase, and ensure that the written steps are explicitly transferred to the planning stage.
Adequate measures not The extent of cause applies to ECR's that include compensatory measures in the taken during the event that a system that is assumed to be operating is lost or taken out of service. The
,development of the ECR feedback provided by the impact reviews from each department must be integrated to drive the execution of and fully understood by all affected parties. The engineering should communicate the
,.compensatory measures. exact actions to be taken by the appropriate personnel in the event that compensatory
- -. measures need to be taken.
Action # 1000819-07 has been created to brief design engineering to raise awareness of error likely situations resulting from inadequate communication in incorporating and integrating impact review comments.
Page 5 of 12
Exeln Latent Organizational Weaknesses - undetected deficiencies in the management control processes (e.g., strategy, policies, work control, training, and resource allocation), or associated values (shared beliefs, attitudes, norms, and assumptions), that create workplace conditions that provoke error (precursors) or degrade the integrity of defenses (flawed defenses).
Basic Work Practices Oversight/Monitoring Communication Organization Structure Computer Issues Program Controls Control of Personal Resources Design/Modification Task Structure Documentation/Procedures/Policies Tools/Equipment Use Equipment/Facility Training/Qualifications Goals/Priorities Values/Norms Housekeeping Work Group Interfaces Industrial Safety Work Group Practices/Processes Management Effectiveness Work Planning/Execution Material Availability Work Scheduling Latent Organizational Weaknesses Questions:
A. Were there latent organizational weakness that were identified as contributing to this event? List and justify. (e.g., workarounds became accepted practices, habits allowed to develop over time, Pre-Job Briefs are felt to be unnecessary)
Latent Organizational Weakness How did it contribute to the event?
that failed Roles / Responsibilities When considering the impact of the construction opening, Opera cn s considered it the responsibility of RP to monitor potential relea.e path and take the appropriate compensatory actions whileRD-on ieTdit the.responsibility of Operations to maintain the-purge system on. )
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O7Vf-N Exelkn" Previous Events: Describe the review of any relevant previous site and industry events for which there is an indication,that the corrective actions to prevent recurrence or industry experience recommnendations were ineffective, ldentit, whether the event is a "Repeat Event.
Previous Events, Oevious.Zvedntflview..-'-
Braidwood Station Containment Penetration flow path not isolated as required by the Technical OE30264 Specification Action Statement atBraidwood Station.
No useful learning opportunities or insight for corrective actions. The creation of an undesired release path stemmed from a misunderstanding of the failure position of an isolation valve.
Hope Creek LER Potential unmonitored release path has existed since plant startup due to 05000354 failure of one of the vacuum breakers to close after a loss of power.
No useful learning opportunities or insight for corrective actions. A design change removed the potential release path.
McGuire Unit 1 - Work inadvertently opened several Containment Purge Ventilation System Failure Number: 217 (VP) containment isolation valves. The cause was the lack of loop specific information in the generic procedure used for calibrating and testing the VP loop. Categorized as a maintenance preventable functional failure.
Corrective Actions: Preventative maintenance procedures and tasks revised.
Millstone Nuclear Unmonitored Airborne Radioactivity Release Paths.
Power Station Unit 1 LER 9709080230 Several conditions-existed on site which could create potential unmonitored airborne radioactivity release paths.
The cause of this event was inadequate program management.
The work control administrative procedure has been revised with appropriate process controls in place to provide a method of monitoring of pathways for potential releases.
There is no operating experience addressing the inability to maintain negative containment pressure or the operation of a purge system during situations where containment integrity is not required.
N . .
Corrective Action: For all causes identified, list the CorrectiveActions (CAs) or Action Items (ACITs) iiiipleniented orplanned to be inipleinented. Identfy' the Action, the Owner. and the Due Dote.
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Exeln CaUse Being C'or rective Actoe (CA orrcionI(ACi Due Date Addressed..-- ..
toren6satory measures (CA) - Revise RCA related ventilation operating Susan Sallade 03/26/2010 included to pr15tV-th`- procedures to require a review of RCS work in Operations release of radiological progress and notify RP prior to operating or material in case of a manipulating ventilation equipment.
ventilation failure were Action # 996823-34 not installed until 8 days after the liner had been
- removed.
Adequate measures not Brief Design engineering on the recent revisions to Mike Harty 3/17/2010 taken during the CC-TM-1 03-1004 that came out of CCA 693870 Engineering development of the ECR under the common cause "Inadequate Design to drive the execution-of Preparation / Reviews SPAC NI / confusing or compensatory measures incomplete.
7Action #1000819-06 Adequate measures not Brief design engineering to raise awareness of Mike Harty 3/17/2010 taken during the error likely situations resulting from inadequate Engineering development of the ECR communication in incorporating and integrating
-to-driyve_theexecution of impact review comments.
compensatory measures.,- Action #1000819-07 Adequate measures not Identify the ECR's that include compensatory Mike Harty 1/13/2014 taken during the measures and interim actions during the Engineering development of the ECR construction phase, and ensure that the written to-drive the execution of steps are explicitly transferred to the planning compensatory measures.- )stage.
_ __ _ _ _ _ _ _ _ _ 5 Page 8 of 12
Exelibn-Apparent Cause Evaluation Ouality Checklist Critical Content Attribue(ci ti for ~a~ccptable p"'dc) E Isthe condition that requires resolution adequately and accurately defined? X 2-=Are the Causal Factors (problems) that resulted in the condition (i.e., equipment failure X, or inappropriate actions) clearly defined?
--For issues that involve inappropriate actions are Human Performance issues (i.e., error defenses and error precursors) clearly defined?
-.For issues that involve equipment failures are the Equipment Performance issues (i.e., parts, components, systems, programmatic problem areas) clearly defined?
Have the causes been-accurately identified and appropriately classified as an Apparent X Cause or Contributing Cause? If the cause was indeterminate, has a risk assessment been performed?
4-.Are the CAs and ACITs adequate to address the causes identified? X
-Do the eeGCAs / ACITrective-atioeps describe the desired end-state and do they clearly identify the action(s) to be taken? .. I ,
eCorrective AotGeis / ACITs that are COMPLETE - State: Complete '/ \ *" f eCeree44re-AetioRs / ACITs that are OPEN - State: Owner, Due Date, and Specific Actions Required
-Have recommended corrective actionsCAs / ACITs been concurred with by the * (b assigned organization? _ _
&.Are the extent of condition evaluation results described and appropriate? g X 6.Are all CR Originator, Supervisor, Screener, Manager and MRC questions, comments, or concerns properly addressed?
7-.Have previous similar site and industry events been evaluated?
ZITMI DOCs 172Wk-.. .PI172AWSAFUdoc SE *r Standard Form No Form Rev No / Status Form Revision Date Form Title WORK PACKAGE ECP QEP 11.01-3 OEI / AFU 21-Feb-06 INSTRUCTION SHEET Project: Unit No: Work Package Number. I Work Package Revision No Status: Work Package Revision Date: Work Package Sheet 38455 1 1720 0 1AFU 21-May-09 33 of 34 Step WORK PACKAGE INSTRUCTION HOLD . RELEASES No. POINT CONST. OTHERS 106 Place cribbing underneath the lift frame assembly end opposite the counter weight as shown on Attachment +1", view 'C".
070 Install / hang the outside Containment opening curtain tarp onto the outside .
curtain track and roller assembly in accordance with the "Outside Tarp Support Attachment Detail" shown on Attachment 5. ___ _ ___0 _.
ý1080 Notify th& ,TýMI ;SGRPRýp~eratioins?()py-Rird'6ttýlýtt" fi FE Y Purge SýýSýisteiCan be'retumed to~normalý.servce.,EnterýthetSGRPOps'aame 0 inrtthbas tiblow., I SGRP Op's Sli~,iDtl ,LTm 1
03
Exekion Attachment #1 - Timeline of Events TMI SGRP RP given notification Dave Ethridge Outside that containment Purge Valves writes containment R2113461 Clearance suspende, opening liner plate Tagged Out for IR#994989 opening curtain (AH-V- IC all tags lifted to allo would be cut in 48 Purge System Maintenance Liner Plate addressing purge tarp hung on track Inspection) purge to be put bac.
hours Shut Down Activities Removed not available / roller assembly completed in service I I I I.
I 11/6 11/7 11/8 11111 11/18 11/19 11/19 11/19