ML20215J396
| ML20215J396 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 10/02/1986 |
| From: | Cutter A CAROLINA POWER & LIGHT CO. |
| To: | Grace J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| IEB-85-003, IEB-85-3, NLS-86-300, NUDOCS 8610240422 | |
| Download: ML20215J396 (7) | |
Text
CD&L Carolina Power & Light Company SERIAL: NLS-86-300 Sip 0071990*5L Dr. J. Nelson Grace, Regional Administrator United States Nuclear Regulatory Commission Suite 2900 101 Marietta Street, NW Atlanta, GA 30303 BRUNSWICK STEAM ELECTRIC PLANT, UNIT NOS.1 AND 2 DOCKET NOS. 50-325 & 50-324/ LICENSE NOS. DPR-71 & DPR-62 RESPONSE TO IE BULLETIN NO. 85-03 " MOTOR-OPERATED VALVE COMMON MODE FAILURES DURING PLANT TRANSIENTS DUE TO IMPROPER SWITCH SETTINGS"
Dear Dr. Grace:
Carolina Power & Light Company (CP&L) hereby submits information requested by IE Bulletin No. 85-03, " Motor-Operated Valve Common Mode Failures During Plant Transients Due to Improper Switch Settings," dated November 15,1985. This information is being provided within the time frame as discussed with Mr. P. Fredrickson of your staff on October 1,1986. The subject Bulletin required that a design basis review be performed and a program be developed and implemented to ensure that switch settings for certain safety-related motor-operated valves (MOVs) are properly selected, tested under simulated conditions, and correctly maintained.
This submittal provides the results of CP&L's review, per action (a) of the Bulletin, of the design basis for the operation of the appropriate MOVs in the H6a Pressure Coolant Injection System and the Reactor Core Isolation Cooling System. In addition, a description of the program and an implementation schedule for completing actions (b) through (d) of the Bulletin are included. The attached information is formatted such that the specific subheadings correspond to the Bulletin item topics.
The IE Bulletin 85-03 requirements will be completed and a final report submitted by~ the end of the BSEP Unit 2 refueling outage. This outage is currently scheduled for completion by April 30,1988.
Should you have any questions regarding this submittal, please contact Mr. Arnold Schmich at (919) 836-8759.
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. B. Cutter - Vice President ABC/AWS/pgp (4044AWS)
Nuclear Engineering & Licensing Attachment cc:
Mr. W. H. Ruland (NRC-BNP) W/A Mr. E. Sylvester (NRC) W/A A. B. Cutter, 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 beliep,,,,,," s and the sources of his information are officers, employees, contractors, and agents p
Carolina Power & Light Company.
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i RESPONSE TO NRC IE BULLETIN 85-03 The following sections provide specific detail on each of the IEB 85-03 action items.
A.
Design Basis Information Action (a) requires that CP&L review and document the design basis for the operation of the MOVs in the High Pressure Coolant Injection (HPCI) and Reactor Core Isolation Cooling (RCIC) Systems required to be tested for operational readiness in accordance with 10 CFR 50.55a(g). This documentation should include the maximum expected differential pressure during both opening and closing of the valve.
The BWR Owners' Group, of which CP&L is a member, developed a program to address action (a) of the Bulletin on a generic basis. The "BWR Owners' Group Report on the Operational Design Basis of Selected Safety-Related Motor-Operated Valves," dated September 2,1986, provided this generic methodology.
Calculations of the maximum expected differential pressures provided in this response are based on this BWROG generic methodology. The valves analyzed as requiring calculation of the differential pressures in the BWROG report are listed in Tables 1 and 2, along with the maximum expected differential pressure in the direction of opening and/or closing. A discussion of the valve function and design basis, assumptions used to determine the maximum expected differential pressure, and differential pressure location (upstream or downstream) are provided in the BWROG report.
B.
Switch Settings Action (b) requires that the correct switch settings be established for the differential pressures calculated in action (a) above. It 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).
The procedures used to set torque switch bypass and position limit switches at BSEP have been reviewed and found to be acceptable. Switches are set 4 percent from the full-opened and full-closed positions unless otherwise evaluated. The 4 percent positions are determined by the total number of handwheel turns for the valve (listed on the data sheet).
The methodology used to determine overload protection set points has been reviewed and found to be acceptable. This methodology (coordination verification and component selection for safety-related valves) has been established using the guidance of Regulatory Guide 1.106 in that all uncertainties with respect to coordination are resolved in favor of the valve performing its design function.
A majority of the valves in this response (see Tables 1 and 2) were tested against the calculated differential pressure, or a larger value, by the valve vendor prior to shipment. The torque switch settings and torque values supplied by the valve vendor have, therefore, been previously verified and will be used as the minimum allowable torque value. The same philosophy will apply to those valves that are
" type tested." (1078NE L/bmc )
~. _
For those valves that do not fall into the above grouping, the torque switch setting required for proper operation against the calculated differential pressure will be determined based on the valve vendor input, the actuator vendor input, and, if necessary, the results of the differential pressure testing. If set points are determined based on lower than calculated differential pressure testing or on a method other than pressure testing, justification will be provided.
C.
Valve Testing Action (c) requires that valve torque switch settings shall be changed, as appropriate, to those determined in action (b) above. This item also requires valve testing at the differential pressure calculated in action (a) above, except where that differential pressure is the result of a line break.
A majority of the valves in this response (see Tables I and 2) were tested against the calculated differential pressure, or a larger differential pressure, by the valve vendor prior to shipment. Therefore, the torque switch settings and torque values supplied by the vendor have been previously verified to be acceptable and additional testing is not required.
Of the remaining valves, additional testing can be eliminated for some, by " type testing," as discussed in the BWROG generic report. As identified in Tables 1 and 2, these valves are identical to others previously tested at the calculated differential pressure by the valve vendor prior to shipment. Therefore, the torque switch settings and torque values supplied by the vendor are acceptable and additional testing is not required for the " type tested" valves.
For tne rernaining valves for which differential pressure test data at the calculated differential pressure cannot presently be found or for which a " type tested" valve cannot presently be found, a test will be performed to demonstrate its operability. This test will use the dif ferential pressure calculated in action (a) above. Where possible, type testing will be performed. Required testing will be performed during the upcoming refueling outages and should be completed by June 30,1987, for Unit I and April 30,1988, for Unit 2. Justification will be provided for testing not performed at the calculated differential pressure.
D.
Control of Switch Settings Action (d) requires that procedures be prepared or revised to ensure that the correct switch settings are determined and maintained throughout the life of the plant.
The Brunswick Steam Electric Plant is currently planning to initiate procedures that state the required limit switch and torque values along with the maximum allowable torque switch value for each valve. These procedures will also contain the necessary requirements for changing a setting. The completion of this action is dependent on the completion of the required testing, therefore, the date for full compliance agrees with that given in action (c) above. 0078NEL/bme)
E. & F.
Schedule and Final Report As noted in the cover letter, this submittal provides a response detailing the results of Bulletin Action (a) and a program to accomplish Bulletin Actions (b) through (d). This response provides CP&L's proposed schedule for the remaining items and a comajitment for a final report in accordance with the requirements of the Bulletin.
Carolina Power & Light Company believes that the schedule submitted is realistic and practical. However, the action plan has several integrated tasks. The milestones represented by the schedule are planning targets and may be adjusted as required for completion. Completion of this effort is contingent upon the next refueling outage for which the schedule may change dependent on capacity factors and forced outages. Adjustments to the current plans may, therefore, be required. We will inform you as necessary should any significant changes arise.
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TABLEl llPCI MOV DESIGN DATA Maximum Expected CP&L Differential Pressure i
Valve Valve Open Close Tag No.
Function (psid)
Comments E41-F001 Turbine S+eam Supply 1105 N/A See Note A, B, and C E41-F002 Steam Supply Inboard Isolation 1105 1105 See Note A, B, and C E41-F003 Steam Supply Outboard Isolation 1105 1105 See Note A, B, and C E41-F004
. CST Suction N/A 43 See Note B E41-F006 injection 1260 1368 See Note A, B, and C E41-F012 Minimum Flaw Bypass 1374 1426 See Note A, B, and E E41-F041
' Suppression Pool Suction 97 30 See Note A, B, and C E41-F042 Suppression Pool Suction 97 30 See Note A, B, and C E41-F059 Cooling Water Supply 30 33 See Note A, B, and C (for Unit 1) and D (for Unit 2)
E41-F075 Turbine Exhaust Vacuum Breaker N/A 27 See Note B and D (for Unit 2)
E41-F079 Turbine Exhaust Vacuum Breaker N/A 27 See Note B and D (for Unit 2)
(1090NEL/pgp)
I TABLE 2 RCIC MOV DESIGN DATA Maximum Expected CP&L Differential Pressure Valve Valve Open Close Tag No.
Function (psid)
Comments E51-F045 Turbine Steam Supply 1105 N/A See Note A, B, and C E51-F007 Steam Supply Inboard Isolation 1105 1105 See Note B and C E51-F008 Steam Supply Outboard Isolation 1105 1105 See Note A, B, and C E51-F010 CST Suction N/A 40 See Note B E31-F013 Injection-1234 1367 See Note A, B, and E E51-F019 Minimum Flow Bypass 1324 1362 See Note A and B f
E51-F029 Suppression Pool Suction 97 30 See Note A and B E51-F031 Suppression Pool Suction 97 30 See Note A, B, and C E51-F046 Cooling Water Supply 1328 33 See Note A, B, and C E51-F062 Turbine Exhaust Vacuum Breaker N/A 27.
See Note B and C (for Unit 2)
E51-F066 Turbine Exhaust Vacuum Breaker N/A 27 See Note B and C (for Unit 2) i 0090ML/pgp )
i i
i NOTES FOR TABLE 1 AND TABLE 2 A)
Opening torque switch is jumpered out.
B)
Closing limit switch is jumpered out.
C)
Valve previously tested against calculated dif ferential pressure and requires no further testing.
D)
Valve identical to one previously tested against calculated dif ferential pressure and, therefore, by " type testing" requires no further testing.
E)
Differential pressures calculated may change pending use of " realistic" valves and removal of excessive conservatism. If a' change occurs, prompt notification will be proiided.
(1090NE L/pgp )
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