ML20081G150
| ML20081G150 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 06/07/1991 |
| From: | Creel G BALTIMORE GAS & ELECTRIC CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9106120261 | |
| Download: ML20081G150 (4) | |
Text
- - - - _ _ _ _
e s
B ALT IMORE GAS AND j
ELECTRIC CHARLES CENTER
- P.O. BOX 1476
- BALTIMORE, MARYLAND 21203 1475 Gronot C CettL C It%,
June 7,1991
~- -
U. S. Nuclear Regulatory Commission Washington, DC 20555 NITENTION:
Document Control Desk
SUBJECT:
Calvert Clitfs Nuclear Power Plant Unit Nos.1 & 2, Docket Nos. 50 317 & 50-318 Response to NRC Region 1 Combined Special Inspection Report Nos.
50-317/91-09 and 50-31Wl-09
REFERENCE:
(a)
Letter from Mr. C. W. llehl (NRC) to hlr G. C Creel (BO&E),
NRC Region I Combined Special Inspection Report Nos.
50-317/91-09 and 50 318/91-09 (blarch 12,1991 to April 5,1991 and April 12,1991), dated hlay 8,1991 Gentlemen:
1.
DESCRIPTION AND C4USE OFT!1E EVIM.
On March 12,1991 at 12:48 a.m., plant operators inadvertently drained approximately 1900 gallons of Reactor Coolant System (RCS) water through the Calvert Cliffs Unit 2 Containment Spray (CS) Ring and Drain Line. 'Ihis incident occurred while the operators were lining up to fill the Unit 2 Safety injection Tanks (SITS). At the time of the event, Unit 2 was in Cold Shutdown at 100 psi on Shutdown Cooling.
The operators involved with this evolution included the supervisor directing the evolution, the on-shift Plant Watch Supervisor (PWS) and four plant operators. Pre evolution briefings were conducted before the operators proceeded with the evolution in which Operations Instruction (01) 3A was used. Two of the operators were directed to close a valve that woidd isolate the RCS from the CS header. Before completing this task, the other two operators, under the direction of the PWS, started to open a valve which created the direct path from the RCS to the CS spray ring, resulting in the inadvertent partial draining of the RCS.
Additionalinformation concerning this event can be found in LER 50 318/91-001.
On March 27,1991, at 11:51 a.m., an inadvertent Safety injection Actuation Signal (SIAS) was initiated on Calvert Cliffs Unit 2. The incident occurred while utility licensed operators were re-energizing the Engineered Safety Features Actuation System (ESFAS) AL Actuation Logic Cabinet. At the time of the event Unit 2 was in Cold Shutdown with an RCS temperature of 140 degrees Fahrenheit and a pressure of 220 psi.
h D
h 9106120261 910607 POR ADOa O'50003t7 3
o PDR g
g
(
- - - - ~ -. - -. - -
o Document Control Desk June 7,1991 Page 2 Two licensed operators were involved with this event, an extra Senior Reactor Operator (SRO) on duty for startup and a Control Room Operator (CRO). A pre-evolution briefing was conducted before the operators proceeded with the evolution in which 01 34, Appendix D and Appendix II were used to re-energize the cabinets. To re energize the cabinets the operators had to reinstate the low Pressurizer Pressure Block Signal Modules before reinstating the SIAS Pressurizer Pressure Modules. The SRO read the procedure to the CRO, who in turn performed each step. The SRO failed to read two CAUTION statements to the CRO and directed him to perform steps that removed the block signal with a valid SIAS signal present, causing the inadvertent SIAS. Additional information concerning this event can be found in LER 50-318/91-002.
The root cause of the CS event was personnel error in that the PWS misinterpreted a procedure which he believed allowed him to perform steps concurrently in OI 3A. Calvert Cliffs Instruction (CCl) 300 allows the concurrent performance of procedure steps if: the steps are evaluated in the sequence listed and found not to be dependent on any other steps in the procedure; and if the Shift Supervisor or Control Room Supervisor (CRS) gives permission to do the steps concurrently. The PWS knew of the requirements of CCI 300 but failed to interpret the requirements properly and directed the manipulation of the subject valves without permission from the Control Room Supervision. Contributing to this event was a lack of proper communication between the operators, an inadeqmte pre-evolution bricting, and the direct involvement of the PWS in a valve manipulation.
The root cause of the ESFAS event was personnel error by the SRO directing the re-energization of the ESFAS cabinet. Specifically, the SRO failed to follow the guidance contained within the two CAUTION statements that were part of 01-34, Appendix 11. By failing to conduct an adequate pre-evolution briefing and by not reading the CAUTION statements to the CRO, the SRO directed the evolution without the benefit of concurrence or feedback from the CRO.
l Due to the short time between the two events and some common elements, an evaluation I
was performed to determine if any generic causal factors might exist between the two events as well as between previous ESFAS events. The final conclusion from this evaluation is that, while there are some areas in need of iniprovement such as pre evolution briefings, supervisory methods, communication, and procedural compliance, their occurrence does not indicate a significant generic problem that would challenge safe plant operation.
11.
COltRECTIVE STEPS TAKEN ANI)ItESt1TS ACI11EVEI).
Personnel actions were taken with the individuals who were involved. Additionally, we determined that there were areas of potentially broader weaknesses. These were addressed in General Supervisor-Nuclear Plant Operations (GS-NPO) Expectations Memos. Guidance concerning pre evolution briefing, supenision, procedure usage, and communications was provided within these memos. The events and GS-NPO expectations were discussed with each crew.
Pre-evolution Briefing - A detailed pre-evolution briefing checklist was developed to provide more structured and consistent briefings. The Shift Supenisor or CRS must decide if a briefing is required and all of the individuals who are involved with the evolution must be present for the briefing. As part of the brieling, consideration is given to the potential results of a failure during an evolution and the barriers that could be put in place to prevent such failures. This pre. evolution briefing checklist has been formally incorporated into CCI-140.
l-
Document Control Desk June 7,1991 Page 3 S,upenision - Guidance on supervision was also reinforced in the GS-NFO Expectations memos. Supervisors were directed to step back and ensure they maintain an overall cognizance of the entire evolution in which they are the supenisor in charge. The role of the supenisor was better defined to prevent detailed involvement or actual hands-on mampulations from interfering with their supenisory perspective.
Procedural Compliance The GS NPO Expectations memo reinforced the proper use of procedures, compliance with procedures, at ' steps that should be taken to change mcorrect procedures.
Communication Proper communication is essential to conducting operations in a safe and quality manner. This message was re-emphasized in the GS NPO memo and specifically stressed the need for communications to be complete such that there is no doubt as to what the intended message is. The importance of detailed repeat-backs and face-to-face communications were also reiterated. CCl-140 was revised to formally capture this guidance.
hianagement obsenations during the recent event free startups of Unit 2 and controFed shutdowns of both units indicate the guidance provided has been beneficial with respect to operator performance. Operations supenision provided around the clock coverage during the startup of Unit 2, and observations of detailed and complete pre evolut on briefings were i
noted. There were many complicated and extensive tests performed during the startups and shutdow ns in which supenision, communication, and procedural compliance were implemented with success.
- 111, CORRECTIVE STEPS WillCil Wil,1,llE TAKEN TO AVOll) Fl!RTilER VIOLATIONS.
The guidance related to supenision will oc formally captured in an Operations policy or L
procedure. This guidance will cover the supenision of Operation's activities in general, along with specific guidance on supenising evolutions involving equipment like ESFAS in the Cable Spreading Room.
To ensure operators retain a complete understanding of critical processes a list of these key processes was generated. A lesson plan for the operator requalification training cycle will be developed to cover these issues.
The specific use of concurrent steps in procedures was evaluated for applicability in each type of operations procedure. A detailed plan was developed to implement the specific changes which will be made to the procedures and to CCI 300. Additional details concerning changes made to CCI-300 will be provided in the response to Unresolved item 50-317/91-09-02 and 50-318/91-09-02.
The lessons learned and corrective actions from these two events apply site wide, to other groups in addition to Operations The Calvert Cliffs Plant General hlanager has established a Task Cirt ie, comprised of representatives from Operations (Circle leader) hiaintenance, Radiation Safety, Chemistry, and Plant Engineering to evaluate the need for a procedure which would deline expectations for procedure usage, pre-evolution briefing, and supenisory l
involvement.
1
6 Document Control Desk
-June 7,1991 Page 4 IV.
- 1) ATE WilEN FUI.1,COMPl.l ANCE WAS ACillEVI:1).
7 Full compliance was achieved on April 6,1991 when the last Operations crew was trained on the GS-NPO Expectations.
Should you have any further questions regarding this matter, we will be pleased to discuss them with you.
NVc truly yours,
/. E-sGct 1
GCC/hiDhi/mdm!bjd cc:
D. A. Brune, Esquire J. E. Silberg, Esquire R. A. Capra, NRC D. G. hicDonald, Jr., N RC T. T. Martin, N RC L E. Nicholson, NRC R.1. hiclean, DNR J.11. Walter, PSC
_