ML20086C034
| ML20086C034 | |
| Person / Time | |
|---|---|
| Site: | Grand Gulf  |
| Issue date: | 06/28/1995 |
| From: | Hutchinson C ENTERGY OPERATIONS, INC. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9507060244 | |
| Download: ML20086C034 (6) | |
Text
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fv Ghson.MS 39150 b 601437 2&]O C. R. Hutchinson 6te besa w omum June 28,1995 owe amy sm l
U.S. Nuclear Regulatory Commission Mail Station P1-37 Washington, D.C. 20555 l
Attention:
Document Control Desk l
I
Subject:
Grand Gulf Nuclear Station Unit 1 Docket No. 50-416 License No. NPF-29 i
Reply To A Notice Of Violation Failure to Properly Control the Configuration of the ADHR Shutdown Cooling System l
Report No. 50-416/95-05-01 (GNRI-95/00104), dated 05/26/95 GNRO-95/00074 Gentlemen:
Entergy Operations, Inc. hereby submits the response to Notice of Violation 50-416/95-05-01.
We share your concern over the cited violation. We understand the potential consequences of the i
lack of adequate decay heat removal during shutdown and refueling conditions. And, we agree that the controls which should have avoided system misalignments were deficient and did not meet Management's expectations.
Operation's management had established a status board which was utilized to track status of systems and valves which may be in a position that deviates from plant procedures. However, this was not controlled by plant processes. Operations has enhanced this process by implementing controls for the use and maintenance of control room status boards. This will aid operations personnel, in that the board is clearly in view of control room personnel and can be easily reviewed for potential system a!ignments which may deviate from the normal system configuration, j
Additionally, we are continuing to foster a culture which integrates the self-verification concept into f
every aspect of our work activities. This concept will be periodically reemphasized to plant personnel, i
We feel that the actions taken as a result of the identified deficiencies will prevent recurrence of similar incidents.
050100 9507060244 950628 M'
PDR ADDCK 05000416 V
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June 28, 1995 GNRO-95/00074 PAGE 2 OF 3 Pl ase let me know if we can provide additional information regarding this violation.
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- truly, CRH/CDH attachment Response to Violation cc:
Mr. J. E. Tedrow (w/a)
Mr. H. W. Keiser(w/a)
Mr. R. B. McGehee (w/a)
Mr. N. S. Reynolds (w/a)
Mr. H. L. Thomas (w/o)
Mr. Stewart D. Ebneter (w/a)
Regional Administrator U.S. Nuclear Regulatory Commission Region ll 101 Marietta St., N.W., Suite 2900 Atlanta, Georgia 30323 Mr. P. W. O'Connor (w/a)
Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Mail Stop 13H3 Washington, D.C. 20555
Att:chment I t3 CNRO-95/00074 Page 1of4 Notice of Violation 95-05-01 Technical Specification 5.4.1.a requires that written procedures be established, implemented, and
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maintained covering the applicable procedures recommended in Appendix "A" of Regulatory Guide 1.33, Revision 2.
Regulatory Guide 1.33, Appendix "A", paragraph 4.e recommends procedures for startup and operation of shutdown cooling systems.
Operating procedure 04-01-E12-1, Residual Heat Removal System, Section 5.13, contains directions for placing the Auxiliary Decay Heat Removal (ADHR) System into service and requires that the ADHR system initial configuration be in " standby". Section 5.10 of this procedure contains directions for placing the system into the " standby" lineup and specifies that the ADHR pump suction valve be open and the plant service water system aligned to provide cooling water flow to the ADHR heat-exchanger.
Contrary to the above,
- 1. On April 15,1995, the ADHR system was not properly aligned in that the ADHR pump suction valve was closed when the system was placed into service. This action resulted in an automatic ADHR pump trip.
- 2. On May 4,1995, the plant service water was not properly aligned to provide cooling water flow to the ADHR heat-exchanger when the ADHR system was placed into service. This action resulted in no shutdown cooling system in operation for approximately three and one-half hours and reactor coolant system temperature increases of approximately 12 degrees F.
I.
Admission or Denial of the Alleged Violation Entergy Operations, Inc. admits to this violation.
II.
The Reason for the Violation. if Admitted Examnle 1 On April 15,1995 plant personnel attempted to place the Alternate Decay Heat Removal system (ADHRS) in service. Upon starting the pumps, a pump trip occurred. Subsequent investigation revealed that the pumps had tripped due to low suction pressure. The low suction pressure condition was the result of the common suction valve (E12F410) for the system being in the closed position.
The ADHRS is designed to only operate in cold shutdown and refueling operations. Prior practices have been that the ADHRS remain isolated (electrically and mechanically) from interfacing plant systems while in Modes 1,2, and 3.
Since the system was to only be used during Modes 4 and 5, attempts to prepare the system for service were not performed prior to reaching Mode 4. However, 4
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Att chm:nt I to GNRO-95/00074 l
Page 2 of 4 i
i during preparations for this refueling outage, a safety evaluation was performed to allow system preparation prior to reaching Mode 4 if the system would be placed in service within the next 30 days.
As specified by the safety evaluation, the system was filled, vented and flushed prior to shutting down for the refueling outage. The system was then placed in a modified Isolate Mode. The system operating instruction only addressed the
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normal Isolate Mode which required E12F410 to be locked closed.
ADHRS was filled, vented, flushed and placed in the modified isolate mode. The system alignment was being controlled using the equipment clearance that had been prepared following the previous refueling outage (RFO6). The particulars of the system alignment were not adequately addressed or documented in places which would have readily flagged operating personnel.
l Additionally, the operating shift that completed the fill, vent and flush on ADHRS i
l did not turn over that the system was in the Standby Mode. However, it was assumed by the on-coming operating shift that the system was in the Standby Mode. The Standby Mode requires the E12F410 to be in the open position.
Following the mode change to OPERATIONAL CONDITION 4, the Division 1 Residual Heat Removal (RHR) Mode of Shutdown Cooling (SDC) was removed from service. Operations personnel, assuming that ADHRS was in the Standby Mode, started the ADHRS pumps. The pumps tripped due to low suction pressure.
The RHR system was restarted in the SDC mode.
Operations personnel placed ADHRS in the Standby Mode in accordance with plant procedures. Personnel restarted ADHRS and its operability was successfully demonstrated.
The investigation revealed several factors that allowed this event to occur.
Inadequate Management of Process Change - Even though a process change had been made to prepare the system prior to the outage, the implementation of the change did not ensure that the procedure addressed system alignment following completion of ADHRS fi!!, vent and flush activities.
Inadequate Verbal Communication - The shift tumover between the operating shifts did not accurately describe the as-left system configuration. This allowed the incorrect assumption to be made that the system had been aligned in accordance with plant procedure.
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i Attachment i13 CNR2-95/00074 Page 3 of 4
. Framnle 2 During restoration of an equipment clearance on May 4,1995, plant personnel attempted j
to clear the tag for the cooling water outlet valve (P44F011) for the Component Coohng
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Water Heat Exchangers. This valve also serves as the cooling water supply valve for ADHRS heat exchangers. Upon attempting to restore the valve to its required SOI position, it was determined that the valve could not be repositioned due to the fuse being j
removed.
The tag was removed and the restored position was changed to closed on the equipment l
clearance sheet. The licensed operator made note of the change and attached it to the l
clearance sheet. Subsequently, the attached note was lost and the fuse for the valve was installed. However, the valve was not repositioned to the required SOI position.
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Division 1 RHR SDC was removed from service in order to perform outage activities and the ADHR system was placed in service. Even though the approved plant instructions, 04-1-01-lE12-1, which were used to place ADHR in service, did state that the P44 l
(nonessential service water) system should be operating in accordance with 04-1 j IP44-1, it did not instruct personnel to verify cooling water flow through the ADHRS t
heat exchangers prior to placing ADHRS in service.
During and following ADHRS being placed in service, operations personnel performed
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increased monitoring activities for reactor coolant temperature. Due to the heat removal j
capacity of ADHRS, a slight temperature increase was expected once ADHRS was placed j
in service. A temperature increase was observed and monitoring continued.
l During this time, nonessential service water to the plant was lost. Since the nonessential l
service water supplies the cooling water for the ADHRS heat exchangers, it was assumed 1
that this affected the performance of ADHRS. Once nonessential service water flow had j
been reestablished, the licensed operator monitoring core temperature indicated that the observed AT seemed to be abnormally low.
i An investigation was launched and revealed that P44F011 was misaligned for the operation of ADHRS. ADHRS operated for approximately three hours without cooling water flow through the heat exchanger. The valve was repositioned and personnel j
observed coolant temperature instrumentation indicating core heat being removed as j
designed.
A subsequent investigation revealed the following casual factor which allowed this incident to occur.
Management methods did not ensure that personnel understood expectations.
The licensed operator revised the restored position by attaching a note to the :
clearance sheet. Subsequently, the note was lost, therefore, the information to reopen the valve was lost. The operator should have made a note in the
Att:chment I t3 CNR2-95/00074 Page 4 of 4 comment section of the clearance to reopen the P44F011 valve when the fuse was installed.-
III.
Corrective Steps Which Have Been Taken and Results Achieved i
Examnle 1 The System Operating Instructions were revised to address partial isolation of ADHRS following system flushing.
Example 2 The System Operating Instructions were revised to insert a flow instrument to indicate cooling water flow through the ADHRS heat exchangers.
Operations Management had meetings with, as well as sending Night Orders to, on shift personnel informing them of this incident and stressing the need to continue our approved.
method of self-verification (the S.T.A.R. concept) and ensuring proper configuration control. The importance of adherence to the protective tagging procedure (e.g. special comments should be written in the comment section of the clearance sheet, not on attached notes) was stressed. Also, the need for proper, clear, and concise communications was stressed.
Additionally, Operation's management had established a status board which was utilized to track status of systems and valves which may be in a position that deviates from plant procedures. However, this was not controlled by plant processes. Operations has enhanced this process by implementing controls for the use and maintenance of control room status boards.
IV.
Corrective Steps to be Taken to Preclude Further Violations No further actions are required.
V.
Date When Full Compliance Will be Achieved All actions necessary for full compliance have been completed.
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