ML20154C264
| ML20154C264 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 09/07/1988 |
| From: | Mcduffie M CAROLINA POWER & LIGHT CO. |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| NLS-88-209, NUDOCS 8809140296 | |
| Download: ML20154C264 (6) | |
Text
1 CD&L Carolina Power & Light Company SEP 0 7 $88 SERIAL: NLS-88 209 l
United States Nuclear Regulatory Commission l
ATTENTION: Document Control Desk l
Washington, DC 20555 BRUNSWICK STEAM ELECTRIC PLANT, UNIT NOS. 1 AND 2 DOCKET NOS. 50 325 6 50-324/ LICENSE NOS. DPR 71 & DPR 62 RESPONSE TO NRC BULLETIN 85 03, SUPPLEMENT 1
References:
(1)
CP&L letter from Mr. L. W. Eury to Dr. J. Nelson Grace (NRC-Region II) dated May 25, 1988, Serial: NLS 88 093
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(2)
BWR Owners' Group Report on the Operational Design Basis of l
Safety-Related Motor Operated Valves, dated Seprember 2, 1986 I
(3)
BWROG 1etter from Mr. R. F. Janecek to Mr. J, h. Sniezek (NRC) l dated March 28, 1988, Serial No. BWROG 8815/0TR (4)
BWROG 1etter from Mr. W. G. Fiock, "BVROC Response to IEB 85 03, Supplement 1",
dated August 4, 1988, Serial l
No. OG8 723-34 l
Gentlemen:
Carolina Power & Light Company (CP&L) hereby submits the initial information requested by NRC Bulletin 85 03, "Motor operated Valve Common Mode Failures During Plant Transients Due To Improper Switch Settings", Supplemest 1, dated April 27, 1988. NRC Bulletin 85 03, dated November 15, 1985, required th e a design basis review be i
performed and a program be implemented to ensure that the switch settings for certain safety related, motor operated valves (MOV) are properly selected, tested under simulated conditions, and are correctly maintained.
Supplement 1 of the Bulletin requires this program to incorporate nine (9) additional MOVs selected by the NRC.
The BSEP program describing the completion of the original Bulletin requirements and the results thereof is detailed in Reference 1.
This program was based upon generic methodology (Reference 2) developed by the BVR Owners' Group (BWROG).
As discussed in Reference 3, the BVROG began development of a generic approach to re evaluate valve differential pressures of the nine (9) NRC selected MOVs considering inadvertent valve operation.
This re evaluation was based upon assumptions outside of the existing BWR Emergency Core Cooling System design basis.
Reference 4 transmitted this generic methodology to CP&L.
Of the nine (9) MOVs selected by the NRC for re evaluation, only five l
(5) are applicable to BSEP.
Design basis information for these MOVs and an implementation schedule for the remaining Supplement actions are
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NLS 88-209 / Page 2 provided as an attachment to this letter. A final report picoviding the program results will be submitted by January 16, 1990.
Please refer any questions regarding this submittal to Mr. Stephen D.
Floyd at (919) 836-6901.
Youts very truly, k
M. A. McDuffie Senior Vice President-Nuclear Generation AVS/ ws (\\cor\\)
Enclosure ec:
Dr. J. Nelson Grace Mr. V. M. Ruland Mr. B. C. Buckley M. A. McDuffle, having been first duly sworn, did depose and say that the information contained herein is true and correct to the best of his information, knowledge and belief; and the sources of his information are officers, employees, contractors, and agents of Carolina Power &
Light Company.
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P c4y, )
Notary (Seah) h My commission expires:
ou J/oj/777
RESPONSE to NRC BULLETIN 85-03, SUPPLEMENT 1 The following sections provide specific detail on each of the NRC Bulletin 85-03, Supplement 1 action items.
A.
Design Basis Information Action (a) requires that CP&L review and document the design basis for operation of the MOVs in the High Pressure Coolant Injection (HPCI) and Reactor Core Isolation Cooling (RCIC) Systems not included in the actions planned or completed in response to the original Bulletin. This documentation should include the maximum expected differential pressure during both opening and closing of the valve.
In addition, when determining the maximum differential pressure for valves that can be inadvertently mispositioned, the fact that the valve must be able to recover from such mispositioning should be included.
Reference 1 provided a report detailing CP&L's completion of the IEB 85 03 program. As indicated in Reference 1, CP&L agreed to re-evaluate five NRC selected MOVs considering inadvertent valve operation.
This evaluation was undertaken with the understanding that assumptions are required that are outside the existing BWR ECCS design basis.
Reference 4 provided the BWRoc methodologf for calculating the maximum differential pressure for the NRC selected MOVs considering inadvertent operation. With the exception of the valves discussed below, this methodology was used for determining the maximum differential pressure for the NRC selected MOVS considering the effects of inadvertent operation. The maximum differential pressures for the NRC selected MOVs are provided in Table 1.
MOV E41-F007 MOV E41 F007 is the HPCI injection valvo test valve.
The test valve is normally open and is only closed to perform testing of the system injection valve.
During an abnormal event, the HPCI injection valve test valve is required to remain open to ensure system flow is directed to the reactor vessel.
The concern for the test valve is whether it could be reopened if inadvertently closed during system initiation, or left closed.
BSEP is currently planning to install a keylock switch for the test valve to eliminate the potential for possible valve mispositioning during system initiation.
These keylock switches will be installed during the 1988 Unit 1 (Reload 6) and the 1989 Unit 2 (Reload 8) refueling outages.
If this valve was left closed inadvertently, an open signal would be received during system initiation, thereby opening the test valve.
The E41 F007 valve would open before the turbine stop valve or injection valve; therefore, the different,ial pressure would be negligible.
The E41 F007 valve was tested by the vendor at the original valve design differential pressure of 1140 psid.
The valve has been stroke tested under the original requirements of the Bulletin, and no 'urther testing is planned.
4 MOV E51-F012 MOV E51 F012 is the RCIC injection valve test valve.
The test valve is normally open and is only closed to perform testing of the system injection valve.
During an abnormal event, the RCIC injection valve test valve is required to remain open to ensure system flow is directed to the reactor vessel.
The concern for the test valve is whether it could be reopened if inadvertently _ closed during system initiation, or left. closed.
BSEP is currently planning to install a keylock switch for the test valve to eliminate the potential for possible valve mispositioning during system initiation.
These keylock switches will be installed during the 1988 Unit 1 (Reload 6) and the 1989 Unit 2 (Reload 8) refueling outages.
If the test valve was left closed inadvertently, an open signal would be received during system initiation, thereby opening the valve. The E51 F012 valve and steam admission valve to the turbine would begin to open at the same time.
The injection valve would begin to open when the steam admission valve is 4% open.
Since the E51 F012 valve would be opening during turbine ramp up, the valve would be off the seat before a significant differential pressure could be generated.
The E51.F012 valve was tested by the vendor at the original valve design difforential pressure of 1140 psid.
This valve was stroke tested under the original requirements of the Bulletin and no further testing is planned.
MOV E51 V8 MOV E51 V8 is the RCIC turbine trip and throttle valve. This valve is normally open when the RCIC system is in standby readiner,s, and remains open during system operation to provide steam flow to the RCIC turbine.
The motor operator on this valvo is only used to open the valve by means of a latch mechanism. The valve is closed by a trip mechanism which releases the latch. The valve is reopened by manually atroking the operator to the closed position, where it latches to the disk mechanism, and then returning the operator to the open position.
The concern for this valve is whether the valve could be reopened if it was inadvertently tripped closed, either manually or automatically.
Using the BVROC nethodology, the calculated maximum differential pressure fer this valve would be 1105 psid. The valve contains a pilot disk whier opens first and is subjected to the full differential pressure.
The open pilot valve and a connected pressure balancing chamber reduce the differential pressure across the main disk to 10% of the full closed differential pressure. Therefore, the maximum differential preasure for the main disk of this valve is 111 psid and for the pilot disk is 1105 psid.
B.
Switch Settings Action (b) requires that for the applicable valves, the correct switch settings be established for the differential pressures calculated in action (a) above. Action (b) also requires the establishment of a program to review and revise, as necessary, the methods for selecting and setting all switches (i.e., torque, torque bypass, limit, overload).
1
7 i
The program for selecting and setting switches was outlined in Reference 1.
This program currently covers the five (5) MOVs applicable to BSEP that required re evaluation as part of Supplement 1 to NRC
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Bulletin 85 03.
This program will be modified, as necessary, to include any required changes in switch or torque settings.
C.
Valve Testine Action (c) requires that valve torque switch settings shall be changed, as appropriate, to those determined in action (b) above. This item also
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requires valve testing at the differential pressure calculated in i
action (a) above, except where that differential pressure is the result i
of a line break.
L i
Testing of the MOVs that required re evaluation under Supplement 1 to the Bulletin will be completed, as required, during the 1988 Unit 1 q
(Reload 6) and the 1989 Unit 2 (Reload 8) refueling outages. The other MOVs governed by this Bulletin have been either: (1) tested against the maximum expected differential pressure; or (2) justified for not i
testing. Justification for not testing has been established as outlined in Reference 1.
r D.
Control of Switch Settings l
Action (d) requires that procedures he prepared or revised to ensure r
I i
that the correct switch settings are de.'. ermined and maintained throughout the life of the plant.
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As stated in Reference 1, procedures to ensure that the correct switch settings are determined and maintained have been es e*W.ished. The five l
(5) HOVs applicable to BSEP that required re evaluation under Supplement i to the Bulletin are currently included in this prograin. This program l
will be revised as necessary.
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E.
& F.
Schedule and Final Reoort
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j As noted in the cover letter, this submittal provides the results of l
.a action item (a) for the five (5) BSEP applicable NRC selected MOVs l
j considering the effects of inadvertent valve mispositioning.
i I
l Action items (b) through (d) for the additional five (5) MOVs are currently scheduled for completion by February 3,1989 for Unit 1 and by j
November 17, 1989 for Unit 2.
These dates correspond to the end of the next refueling outages for Unit 1 and Unit 2, as required by the 1
i Bu'11e tin.
Based on this refueling outage schedule, a final report l
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detailing the results of any required testing will be submitted by 1
January 16, 1990.
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l CP&L Haximum Expected Valve Tac No.
Valve Function Rifferential Pressure C23 Tents l
QPID (Psid) Close E41-F004 CST Suction 43
'43 Note A E41 F007 HPCI Injection Valve N/A N/A Note 3 Test Valve E51 V8 Turbine Stop Valve 111 N/A Notes A and C E51-F010 CST Suction 43 30 Note A E51 F012 RCIC Injection Valve N/A N/A Note B Test Valve Notes:
A)
Inadvertent valve operation considered for differential pressure.
B)
Inadvertent valve operation not considered since a keylock switch will be installed.
C)
Pilot disk opens at 1105 psid.
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