ML20246E832
| ML20246E832 | |
| Person / Time | |
|---|---|
| Site: | LaSalle  |
| Issue date: | 08/18/1989 |
| From: | Kovach T COMMONWEALTH EDISON CO. |
| To: | Davis A NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| 0248T, 248T, NUDOCS 8908300037 | |
| Download: ML20246E832 (7) | |
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. DC h 7 - } Commonwrith Edison j::k" - ; 7,7 West Adams St>.eet Chicago Illinois -
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1 33ress Reply to. Post Office Box 767 o.
~ Chicago. Illinois 60690 0767.
August 10, 1989 t
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Mr. A. Bert Davis Regional. Administrator l6 U.S. Nuclear Regulatory Commission Region III-
. 799 Roosevelt Road Glen Ellyn, If, 60137
'aSalle County. Station Unit's 1 and 2--
Subject:
L Revised Response to Inspection Report Nos. 50-373/89012 and 50-374/89012 Routine Safety Inspection NRC Docket Nos. 50-373 and 50-374 Reference (a):
H.D. Shafer letter to Cordell Reed dated June 20, 1989.
-(b):
H.E. Morgan letter to A.B. Davis dated July 20,1989 :
Dear Mr. Davis:
This letter is in response to the inspection rohducted by Messrs. R.
Lanksbury, R. Kopriva, A.H. Bongiovanni and D. Jones, on April 25 through June 9, 15C9, of certain activities at LaSalle County Station. Reference-(a) indicated that certain activities' appeared to be in noncompliance with NRC requirements Reference (b) submitted Commonwealth Edison Company's response to the Level-IV Notice of Violation and additional concerns.
Per the request of your staff, the attached document provides Commonwealth Edison's revised response which further addresses the Level-IV Notice'of Violation and additional concerns raised by the inspection report.
If you have any further questions regarding this matter, please C
contact this office, g
Very truly yours, mo
/
'ovarh Nuclear L censing Manager 8e Attachment
' s ca MG cc: NRC Resident Inspector - LSCS s
P.C. Shemanski - Project Manager, NRR s(
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AIBCEERI
' REVISED RESPONSE TO IR 50-373/89012: 50-374/89012 l
VIOLATIONE 10 CFR 50,' Appendix B,-Criterion XVI, requires that licensee's take prompt.
corrective' actions to assure that conditions' adverse to quality are promptly identified and corrected and that corrective. actions are taken to preclude repetition.
Contrary to the above, on April 5,1989, and again on April:19,1989,- the-licensee. failed to promptly identify the cause of the failure,'and take corrective action to prevent recurrence, of the IVR05YA reactor building ventilation isolation damper.
Corrective action to prevent recurrence was.
not taken until April 24, 1989.
In addition, the failure mechanism of the solepold valves has been known since at least February 1985, but the licensee has not implemented corrective actions to prevent recurrence as
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- of the date of the end of this inspection.
CORRECIlyE ACTION-TAKEN AND RESULTS ACHIEVID The two ASCO HT series solenoid valves were replaced with rebuilt solenoid C
valves of the same series. The two Parker air cylinders were replaced with new air cylinders of the same. type.
Damper IVR05YA now closes-within
'the time' interval specified by the Technical Specifications.
. CORRECTIVE ACTION _TAKEN TO 'AVOIE_FURTHER VIOL &Il0B
' Component replacement packages for the installation of the ASCO NP series valves have been approved. The NP. series. valves at the station have been sent to.ASCO for rebuilding prior to installation. This is in compliance with ASCO's service bolletin which was dated January 30, 1989. After the solenoid valves are rebuilt and returned to the station, the valves will be installed at the dampers of each unit during the first outage of sufficient duration. ASCO has indicated it-will expedite the order and it is expected that.the NP series valves will be installed during Unit I third refueling outage (September, 1989) and Unit 2 third refueling outage (March, 1990).
Until the component replacement is installed, the HT series solenoid valves will be rebuilt or replaced every refuel outage.
The Parker air cylinders will also be replaced at an interval corresponding to every refuel-outage, pending determination of the optimum interval of replacement.
These two preventive maintenance items are now on the station's General Surveillance schedule.
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laorderJtoassistinthetimelydiagnosisofdamperproblems,LOS-CS-Q1,
" Secondary Containment Operability Test," is being revised to have a representative from both the Electrical Maintenance department and the Technicel Staff present at the surveillance.
The above actions'Here.taken.to address the'VR damper problem.
In addition, to addrc:s the more general issue of adequate investigations and
. failure evaluations., appropriate procedure (s) will be revised to provide additional guidance for restoring inoperable equipment to operable status.
The revision will address the following:
a)
If no specific cause of failure can be identified all avenues must be explored to deterinine that. the equipment remains, operable.. It. is envisioned that cases may arise where a piece of equipment must be returned to service and declared operable after all reasonable efforts to determine the cause have failed. This should be.done only after a careful evaluation is completed and after it is determined that this is the only option available for determining the cause.
In these cases, close monitoring of the equipment is necessary untti assurance of' continued operability is established or the root cause of.the. failure is determined.
It is not necessary that the root cause (for example why an instrument drifted outside the Tech Spec setpoint or why the preventative maintenance program did'not schedule a filter to be replaced often enough) be determined prior to
. declaring the equipment operable as long as the work that was performed is sufficient to ensure that the equipment will perform its required function (s) while the root cause is being-determined.
b)
Actions to determine the root cause will be initiated in a timely manner to preclude additional failures.of the same type for this or similar equipment.
c)-
If during the root cause determination cdditional information becomes available which affects the original conclusion of operability, prompt action must:be taken to ensure continued operability or the appropriate equipment must be declared inoperable until corrective actions have been taken.
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Persornel on the Technical Staff, Regulatory Assurance, and Maintenance l
departments have been trained on root cause analysis techniques.
Additional personnel in these and other departments will'be trained later in 1989 continuing through 1991 and periodically thereafter to ensure that trained personnel will be involved in determining the root cause when appropriate.
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1 DATE OF FULL COMPLIANCE full compliance has been achieved with the repair of damper IVR05YA and the establishment of preventive maintenance schedules for the solenoid
!alves and air cylinders.
Although the solenoid valves did not cause the damper failures during this sequence, the solenoids will be upgraded to the NP. version during LlR03 and L2R03.
The appropriate procedure revision (s) will be completed by September 30, 1989.
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The' concerns mentioned in paragraph 12 of.the inspection report'are
. addressed below.
CONCERN 1:
The licensee's' declaring the IVR05YA damper operable on April'5, 1989, after four consecutive failures:followed by five consecutive satisfactory closures ~with no work performed on the.
. system to determine the. root cause.
s-CONCERN 2:
The licensee assuming the failure on April 19, 1989 to be caused by the solenoid valve and not promptly disassembling the valve
'to determine if it was the cause of the failure prior to' declaring the damper operable.
CONCERN 3:
The licensee's failure to promptly take action (i.e., declare the damper inoperable and pursue corrective action) when the disassembly of the solenoid valve revealed it was not the cause-of the failure.
RESPQMSE:
The procedural enhancements discussed in the response to Violation 373/89012-02 also addresses Concerns 1, 2 and 3.
That is, the following will be added to appropriate procedures to provide additional guidance for restoring inoperable equipment to' operable status:
a)
If no specific cause can be identified, all avenues must be explored to determine that the equipment remains operable.
It is envisioned that c&ses will arise where a-piece of equipment must be returned to service and declared operable after all reasonable efforts to determine the cause have failed.
This should be done only after a careful evaluation is completed and after it is determined that this is the only option available for determining the cause.
In these cases close monitoring of the equipment is necessary until~ assurance of continued operability'is established or the root cause of the failure is determined.
It is not necessary that the root cause (for example why an instrument drifted outside the Tech Spec setpoint or why the preventative maintenance program did not schedule a filter to be replaced often enough) be determined prior to declaring the equipment operable as long as the work that were performed is sufficient to ensure that the equipment will perform its required function (s) while the root cause is being determined.
b)
Actions to determine the root cause will be initiated in a timely manner to preclude additional failures of the same type for this or similar equipment.
c)
If during the root cause determination, additional information becomes available which affects the original conclusion of operability, prompt action must be taken to ensure continued operability or the appropriate equipment must be declared inoperable until corrective actions have been taken.
x Personnel on the Technical Staff, Regulatory Assurance,-and-Maintenance departments have been trained on root cause analysis techniques. ~ Additional' personnel in these_and other departments will be trained later in 1989 continuing through 1991 and regularly scheduled thereafter to ensure that trained personnel will'be involved in determining the root cause of failures when appropriate.
Procedure revision (s) will be completed by September 30,.1989 CONCERN 4:
'The licensee's failure to adequately determine the service-life of the solenoid valves and the failure to ensure that the solenoid valves were changed out prior to the end of what they thought the service life to be.
RESEQRSE:
The recommended service life'of the ASCO HT series solenoid valves is 4 years for the resilient parts, and 30,000 hours0 days <br />0 hours <br />0 weeks <br />0 months <br />, or approximately 3.4 years, for the coil when energized.
This information had been conveyed to.the station froni ASCO via Sargent & Lundy in a November, 1984 letter. The solenoid valve failures at the station had all.been a result of " soft parts" embrittlement, and none have been attributed to coil failure.
The limiting factor in determining solenoid valve service life is thus properly considered to be the life of the resilient parts. Once the originally installed solenoid valves were teplaced, none of the solenoid valves have been kept in service beyond the manufacturer's recommended service life of 4 years, and none have failed.
Rebuilding or replacement of these valves has been put on the station survelliance schedule, which will assure their replacement after a very conservative service life 1
of approximately 18 months. This measure has been in effect since September,1988, and, by itself, should be even more effective ir. minimizing the likelihood of solenoid valve failure than will the replacement with the NP series.
COEERN 5:
When the lower solenoid valve for damper IVR04YA was scheduled for replacement due to its service life having expired, the I
replacement did not occur as scheduled and damper IVR04YA subsequently failed.
RESPONSE
Work request L75842 was written on February 2, 1988 to rebuild or replace the bottom solenoid of damper IVR04YA.
This was intended to be completed during L1R02, but the work was not L
identified as being outage-related, and was set aside in deference to higher priority outage work.
The Operating Engineer reviews the work requests for his unit and assigns priorities.
In this case the work was not properly i
prioritized.
In the future the system engineers will monitor i
l work requests which are written on their systems to assist the Operating Engineers in setting appropriate priorities.
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Thel licensee committed to a component change.in 1985 forathe solenoid valves. ~To date this change has not' occurred.
The licensee does not appear to have-been very' aggressive in-pursuing this change.
RESEQNSE:
The' station should have pursued the resolution of this. problem more aggressively.
The pris,ary reason the replacement was not given a higher priority'was the fact.that the NP valve was-i I
basically'the same as the!HT version, except that the elastomers are.more tolerant of radiation fields.
Because these solenoid-valves are not in a significant radiation field, the change out was-not aggressively pursued.
In the past, component-.
. replacements were not included in an integrated schedule so that j
appropriate priority could be placed on each task in relation to other. items requiring replacement. Component replacements in the future will be placed in a data base with appropriate milestones established.
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