ML20113G665
| ML20113G665 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 04/09/1992 |
| From: | Shelton D CENTERIOR ENERGY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 1-981, NUDOCS 9204160004 | |
| Download: ML20113G665 (4) | |
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Donald C. Shenon 300 Maison Avente Vce Pre 2.5 Nuclew Toledo, OH 06520001 Davis Besie (419)249 2300 Docket flumber 50-346 License llumber llPF-3 Serial 11 umber 1-981 April 9, 1992 tinited States lluelear Regulatory-Commission-Document Control Desk Washington, DC 20555
Subject:
- ' Response to Inspection Report flumber 50-346/92002 Gentlemen Toledo Edison (TE) has received Inspection Report 92002 (Log flumber 1-2628) dated March 13, 1992, and provides the following response.
Violation 92002-02:
Technical-Specificatinn 6'.8.1.a requires,tha't-written
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procedures. be established, implemented and maintained covering activities recommended in Appendix A-of-Regulatory Guide.1.33, llovember 1912.
Regulatory
-Guide 1.33, Appendix A lista procedures.for operation of Containment. Atmosphere Systems.
DB-OP-06417. Rev-0 CTMT Vessel Atmospheric H'2 A""l I
System operating procedure, step-3.1.4.d. requires that-four (4) AC POWER circuit breakers.in the ' rear of the
!!ydrogen Analyzer cabinet be closed.--
-Contrary.to the-above. on February.30,f1992'.: f rom approximately 8:52 a.m.'and until 6i46-p.m., one of four
- AC POWER circult' breakers inithe rear of the:Ilydrogen"
. Analyzer was opened making the #1 ContainmentLilyurogen -
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. Analyzer System inoperable.-. The. system was is. operable for almostl ten (10) hours-before operators observed _the-c ondit ion'.-
Responses-
-Acceptance or D*nialJof the' Alleged Violation-
. Toledo Edison' acknowledges the alleged violation.
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Docket Humber 50-346 License Humber "PF.3 Serial Number 1-901 Page 2 Reason for the Violation on February 10 1992 at 6:43 p.m., with the plant in liode 1, it was discovered that both channels of the Containment flydrogen Analyzer were inoperable.
Channel 2 of the hydrogen analyzer had been remeved from service for maintenance at approximately 12:10 a.m. and the action statement for Technical Specification 3.6.4.1 which allows operation for 30 days with one inoperable hydrogen analyzer, was entered.
1 A review of the computer alarm records was initiated after a teactor operator noted a below scale reading-on containment flydrogen Analyzer Channel 1.
During this review, it was discovered that computer point A302. CTHT 112 Channel 1. had entered-the alarm state at 8:$2 a.m.
The Assistant Shiit Supervisor was notified of thia condition at 6:30 p.m.
An investigation was initiated-and at 6:43 p.m. the AC input breaker associated with.
Cnannel 1 was verified to be open.
Technical-Specification 3.0.3 was entered at 6:43 p.m. because the action statement in Technical Specification 3.6.4.1 did not contain a provision for two inoperable _ channels of the hydrogen analyzer. At 6:46 p.m.,
the breaker was closed, a channel check was performed which demonstrated the operability of Channel 1 of the hydrogen analyzer.
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and Technical Specification 3.0.3 was exited.
The cause of this event was the inadvertent openinB of the Channel i hydrogen analyzer AC input breaker while Channel 2 was removed from service.
This required entry into Technical Specification 3.0.3 since.both channels of the Containment Hydrogen Analyzer were out of service.
and the action statement in Technical Specification 3.6.4.1 did not contain a provision for two inoperable channels of the hydrogen, analyzer.
The inadvertent opening of the Channel 1 hydrogen analyzer AC. input breaker can most probably be attributed to a malfunction of the' breaker. Maintenance personnel were at the hydrogen analyzer; cabinet when the breaker' opened. _Both channels of the hydrogen analyrer are located in this. cabinet, sepacated by a metal barrier.
The maintenance personnel had_the doors to each side of the cabinet open-in order to compare the configuration of-Channel:2 circuitry to that of Channel-1.
During this comparison, the-Channel 1 breaker box cover was. loose: and was 'slightly jarred by maintenanca personnel.
Due.to the level of noise in the area, the-tripping of the breaker would not have been audible.' While opening of the breaker'could be due-solely to mechanical shock induced by the maintenance
. personnel, it is believed that their actions vould not 1-
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Socket Number 50-346 nense Number HPP-3 tal Humber 1-981 Page 3 have been sufficient to jar the breaker open.
This scenario is supported by a previous incident. In January 1992, when the breaker was inexplicably found open during performance of a channel calibration prior to returning Channni 1 to service.-
During the review of this event, it was determined that enhancements to the control room alarm system are warranted.
Anomalies exint in the computer alarm system which contribute to the number of continuous and extraneous computer alarms.
In addition, neither the screen display nor the hardcopy printout of the computer alarms provides an indication of which alarms are associated with Technical Specification equipment.
This makes it more dif ficult for the operators to determine the appropriate action for each alatm. _Au a result of-these problems, the confidence of operations personnel in the computer alarm system has been reduced.
Corrective Action Taken and Results Achieved
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On January 16.-1992, the NRC issued Amendment 168 to the Davis-Besse operating bicense.
This amendment revised Technical Specification Section 314.6.4.1 by adding an additional action statement, applicable when both hydrogen analyzers are inoper:ble. which allows 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to return one of the two inoperable hydrogen analyzers to operable st atus before initiating a plant shutdown.
Although Amendment 168 was issued, Toledo Edison had not yet implemented the change. Amendment 168 was implemented on February 11, 1992.-
An Operationn Hight Order was-issued on February 14, 1992, which' requires review c~ the computer alarms. list at least twice per shift with logging of_thisfreview and actions taken in response to computer alatms.
The' Channel I hydrogen analyzer AC input breaker was.
replaced on February 20. 1992.
Testing was conducted on
- the removed breaker, however.? inappropriate breaker operation could not.be reproduced.
bicense Event:Repori (I.ER).92-001 was' issued'on
' Harch 10, 1992, in accordance withe 10 CPR 50.73(a)(2)(1) describing this event.
Corrective Act ions to -Prevent Recurrence Due-to the configuration of the hydrogen analyzer circuitry,' with both channels in a single cabinet.-.
better labeling and access control will be-established to reduce the potet.tial of inadvertent operation.
The~
hydrogen analyzer. cabinet is now-locked with access e
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_. 1
,2
- _ -. - - - ~ -.. - - - - ~.. -. __. ~ _ _..
t Docket 11 umber 50-346 License Number NPF-3 4
Setial Number 1-9P1 Page 4 controlled by the Shift Supervisor.
The ability to separately lock each channel will be provided by June 1.
1992.
In addition, labeling will be enhanced to provide channel indication on each cabinet door a..d labels for
' r the AC input breakers.
The labeling enhancements will be completed by April 30, 1992.
A review team has been formed to address possible improvements in the computer alarm system.
The first meeting of this team was held on February 20, 1992.
It is expected that this team will recommend improvements which will make identification of significant computer alarms easier for control room operators.
The term is expected to provide an edited list of computer points to be monitored by the Control Room CRT by June-1, 1992.
This will delete a number of unnecessary points and greatly improve on the " nuisance" factor experienced by the operators.
Final results of the computer alarm system improvements are expected by December 1, 1992 E
for management review.
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Date When Full Compliance Will Be Athleyd Full compilance with procedure DB-0P-06417. Revision 0 was' achieved at 6:46 p.m. on February 10, 1992, when the AC input breaker for channel 1 of the containment;.
i Hydrogen Analyzer was returned to its. proper position.-
The corrective actions to prevent recurrence noted above will be completed by December 1, 1992.
Should you have any questions o_r require additional'informat' ion, please contact Mr. R. W. Schrauder, Manager. Nuclear bicensing, at (419) 249-2366.
Very trul yours,
/
6 NRP cci A. B. Davis, Regional Administrator.'HRC Region III J. B. Hopkins, NRC/NRR DB-1 Senior Project.Hanager
.W.-Levis, NRC-Senior Resident-Inspector j-Utility Radiological Safety Boat.d
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