ML20045C346
| ML20045C346 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 06/14/1993 |
| From: | Storz L CENTERIOR ENERGY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 1-1015, NUDOCS 9306220391 | |
| Download: ML20045C346 (5) | |
Text
CENTERIOR ENERGY 6200 Dok Tree Boulevard Mall Address independence OH PO Box 94661 716-447 3100 Cleveland OH 44101-4661 Docket Number 50-346 License Number NPF-3 Serial Number 1-1015 June-14, 1993 United States Nuclear Regulatory Commission Document Control Desk Vashington, D. C.
20555 Subj ec t:
Response to Inspection Report 93011 Gentlemen:
Toledo Edison (TE) has received NRC Inspection Report 50-346/93011 (Log Number 1-2847) and discussed the issues raised in this Inspection Report vith the NRC in a meeting held on June 3, 1993. The following constitutes i
TE's response to Violation 93011-01.
Violation:
Technical Spacification 6.8.1.a requires that vritten 93011-01 procedures be established, implemented and maintained covering activities referenced in the applicable procedures in Appendix A of Regulatory Guide 1.33, dated November 1972. Regulatory Guide 1.33, Appendix A, section A.4, lists adherence to administrative procedures as one of these activities.
Davis-Besse administrative procedure, DB-0P-00000, Revision 2, " Conduct of Operations," section 6.8.5, requires that when a procedure section requires shift sepervisor or assistant shift supervisor review and signoff, then the review and signoff must be completed before other actions are initiated that could be impacted by an incomplete or improperly performed section.
Contrary to the above, on April 13, 1993, operations personnel did not properly implement administrative procedure, DB-0P-00000, Revision 2.
Specifically,
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personnel performed attachment 10 in the body of
' 1 p l8J u DB-0P-06012, section 4.3, " Recirculation of the BVST using Decay Heat Pump #1 While the RCS is on DH Cooling," prior to obtaining a review and signoff of the prerequisite section of DB-0P-06012, as required.
Because attach'nent 8 in the prerequisite section of the procedure was not completed, about 13,570 gallons of water from h@
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Docket Number 50-346
. License Number NPF-3 Serial Number 1-1015 Page 2
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the reactor coolant system were inadvertently transferred to the borated water storage tank.
l This is a Severity Level IV violation (Supplement I).
Response
Acceptance or Denial of the Alleged Violation Toledo Edison acknowledges the alleged violation.
Reason for the Violation The primary cause of this violation was a personnel failure to properly follow plant procedure DB-0P-06012, " Decay Heat and Lov Pressure Injection System Operating Procedure,"
which requires DH 1517 to be closed as a prerequisite to starting alignment of decay heat train 1 for borated water storage tank (BUST) recirculation.
At 1351 on April 13, 1993, the plant was in Mode 5 at 110 degrees F vith the reactor coolant system filled and vented.
Pressurizer level was approximately 80 inches vith i
a nitrogen bubble and the reactor coolant system (RCS) at 38 psig. Decay heat train 2 vas in service with decay heat train 1 in standby.
The draining of the RCS resulted from an improper sequencing of a valve lineup in decay heat. train 1 while preparing to recirculate the BVST in accordance with plant procedure DB-0P-06012.
The recirculation of the BVST vas to be done in preparation for obtaining a BVST sample.
Also, this was the required alignment of decay heat train 1 for an upcoming integrated test of the safety features actuation system (SFAS). The equipment operator who performed the decay heat train 1 alignment opened' valves DH 66 and DH 68, creating a flovpath,from the RCS suction valves to decay heat pump 1 through the decay heat cooler to the BVST. However, because the equipment-operator.vas inappropriately performing Attachment 8 (prerequisites) of DB-0P-06012 in parallel with. Attachment 10 (valve lineup) valves DH 66 and DH 68 vere opened prior to closing-valve DH 1517. Closing of valve DH 1517 vould have blocked the i
flovpath from the reactor coolant system hot leg-to the j
suction side of decay heat pump 1.
In this configuration,
-i an open flovpath from the RCS to the BUST vas established.
Although decay heat pump 1 was not operating,1the 38 psig RCS pressure and the water head differential between the-i RCS and the BVST provided the motive force for the t
l inadvertent transfer of reactor. coolant to the BVST.
Control room operators quickly observed the decreasing pressurizer level and took actions to determine and correct the cause.
When the equipment operator reported that he l
l u
Docket Number 50-346
, License Number NPF-3 1
Serial Number 1-1015 Page 3 had opened valves DH 66 and DH 68 the flovpath was immediately recognized and actions were taken to isolate decay heat pump 1 suction to the RCS.
Approximately 22 minutes elapsed from when the open flovpath was established until valve DH 1517 was' closed, terminating the event. During this time 13,570 gallons of reactor coolant vas transferred to the BVST.
At no point was decay heat removal capability lost. Decay heat pump 2 suction pressure remained greater than 40 psig and flov remained unchanged at approximately 3100 gpm during the entire-j event. RCS coolant temperature did not increase during the i
event.
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There were additional causal factors associated with' this j
event.
Several major plant evolutions such as preparing for integrated testing of the SFAS, high pressure ~ injection recirculation, containment spray recirculation, and BVST fill were either in progress or recently completed at the time of the event. Operations personnel undertook an overall level of activity which reduced the operating shift crew's ability to effective 2y work together as a team to perform critical plant evolutions.
In addition, operator knowledge of shutdown operations could be improved.
Corrective Action Taken and Results Achieved At approximately 1413 valve DH-1517 was closed, terminating the event.
A Transient Assessment Program (TAP) team was assembled and.
commenced an investigation prior to shift turnover.
The J
team examined the event in detail, explained contributing causes to the event, and proposed corrective actions to be taken.
The equipment operator who was performing Attachments 8 and 10 was counseled regarding his. actions during this event and the operating crev which was on-shift at the time of the event was disciplined.
Operations management discussed this event with each shift j
supervisor and operating crew. The discussion reinforced
,I the procedural adherence policy in addition to focusing on j
the use of plant drawings prior to executing system status f
changes and the need to improve the quality of communications on shift.
i Corrective Actions to Prevent Recurrence Toledo Edison plans to take the following corrective actions to prevent recurrence,
~.,. _ _ - - + - -., _.,. _. -. _ _ -., _.
Docket Number.50-346
. License Number-NPF-3 Serial Number 1-1015 Page 4 NRC Inspection Report 50-346/93011 and this violation response vill be required reading for operations personnel.
Lessons learned from this event will be reviewed in operator requalification training.
Procedure DB-0P-00000 vill be revised to more clearly require the completion of prerequisites prior to performing the procedure section.
Procedure DB-OP-06012, vill be enhanced to incorporate lessons learned-from this event e A procedure adequacy review of existing outage related operations procedures vill be completed. This review is intended to identify shutdown operations system lineups which, due to system interfaces, could result in
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inadvertent water transfers. The review vill include an assessment of the adequacy of the procedure for shutdown operations.
Toledo Edison has requested that INPO provide their "INP0' Control Room Teamwork Development Course" to Davis-Besse operations personnel. This is a 28 hour3.240741e-4 days <br />0.00778 hours <br />4.62963e-5 weeks <br />1.0654e-5 months <br /> course which provides dedicated training on crew dynamics and communications.
Lessons learned from this event, including the need to control the overall level of control room activity, vill be incorporated into pre-outage operator requalification training.
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Date Vhen Full Compliance Vill Be Achieved l
Required reading of NRC Inspection Report 50-346/93011 and.
4 this violation response vill
- completed by July 15, 1993.
Lessons learned from this event including the need to control the overall level of control room activity, vill l
be reviewed in operator requalification training by July 15, 1993.
Revisions to DB-OP-00000 and DB-0P-06012 and the procedure j
adequacy reviev vill be completed by July 30,.1993.
j The INPO development course is scheduled to be given during four veeks in June and July, 1993.
The revised pre-outage operator requalification training-vill be provided to operating crews prior to 9RF0'.
j l
l
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Docket Number 50-346
. License Number NPF-3 Serial Number 1-1015 Page 5 Conclusion Toledo Edison recognizes the significance of this event and has taken appropriate management actions. A TAP team was assembled and commenced an investigation prior to shift turnover on the day of the event. In addition, extensive corrective actions have been initiated including procedure revisions, a procedure adequacy review, enhanced operator requalification' training, and INP0 training on control room teamwork.
Toledo Edison is reinforcing procedure adherence at Davis-Besse.
Inspection Report 50-346/93011 states that this event is similar to an event which occurred in December 1992. The December 1992 and the April 1993 events both involved procedural problems although the root causes were different. The December 17, 1992 event occurred because an equipment operator incorrectly chose valve positions on a lineup sheet. The lineup was not reviewed and. approved by a senior reactor operator prior to starting the #1 Clean Vaste Monitor Tank pump. As a result,.the pump was operated with the tank outlet control valve (located on the suction side of the pump) closed..The corrective actions taken in response to the December 1992 event were intended to ensure that proper Shift Supervisor or Assistant Shift Supervisor review and approval'is obtained, before proceeding with subsequent procedural steps, when required by procedure.
The April 13,-1993 event resulted from a personnel error on the part of the equipment operator who performed Attachment 8 and Attachment 10 of DB-0P-06012 in parallel. Procedural actions taken during the April 13, 1993 event did not reach the point when Shift Supervisor or Assistant Shift Supervisor review and approval was necessary (i.e. at the completion of Attachment 8 or 10). Therefore, the root cause of this event was personnel failure to properly follow plant procedures.
Should you have any questions or require additional information, please contact Mr. Robert V. Schrauder, Manager - Nuclear Licensing, at (419) 249-2366.
Very truly yours,
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h9'
~
L. F. Storz Vice President - Nuclear 2
4 MAT /dle i
cc:
J. B. Hopkins, NRC Senior Project Manager J. B. Martin, Regional Administrator, NRC Region III S. Stasek, DB-1 NRC Senior Resident Inspector Utility Radiological Safety Board 1