ML20203C873
| ML20203C873 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 07/14/1986 |
| From: | Larson C NORTHERN STATES POWER CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| IEB-85-003, IEB-85-3, NUDOCS 8607210092 | |
| Download: ML20203C873 (11) | |
Text
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4 Ow0 Northern States Power Company 414 Mcollet Matt Minneapohs. Minnesota 55401 Telephone (612) 330-5500 July 14, 1986 Mr J G Keppler Regional Administrator - Region III US Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137 PRAIRIE ISLAND NUCLEAR GENERATING PLANT Docket Nos. 50-282 License Nos.
DPR-42 50-306 DPR-60 Response to IE Bulletin 85-03 The attached information is offered in response to Item (e) of IE Bulletin 85-03, " Motor-Operated Valve Common Mode Failures During Plant Transients Due to Improper Switch Settings." Results of Item (a) are included, as are the program to accomplish Items (b) through (d) and a schedule for completion of these items.
Please contact us if you have any questions about this response.
- lW C E Larson Vice President Nuclear Generation CEL/EFE/ dab c
- NRR Project Manager, NdC Resident Inspector, NRC Document Control Desk, NRC G Charnoff Attachment 8607210092 860714 PDR ADOCK 05000082 IS(\\\\
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JUL 101986
UNITED STATES NUCLEAR REGULATORY COMMISSION NORTHERN STATES POWER COMPANY Docket No. 50-282 PRAIRIE ISLAND NUCLEAR GENERATING PLANT 50-306 RESPONSE TO IE BULLETIN 85-03 Northern States Power Company, a Minnesota corporation, by this letter dated July 14, 1986 hereby submits the response to IE Bulletin 85-03 for the Prairie Island Nuclear Generating Plant.
This letter contains no restricted or other defense information.
NORTHERN STATES POWER COMPANY by N,
C E Larson Vice Preside Nuclear Generation
/ h day of 4d
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before me a notary public in and On this for said County, personalI(/ appdred C E Larson, Vice President, Nuclear Generation, and being first duly sworn acknowledged that he is authorized to execute this document on behalf of Northern States Power Company, that he knows the contents thereof and that to the best of his knowledge, information and belief, the state-ments made in it are true and that it is not interposed for delay.
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3 RESPONSE TO IE BULLETIN 85-03, ITEM (e)
I.
HIGH PRESSURE SAFETY INJECTION SYSTEM A.
Definition - Safety injection pump suction from the boric acid storage tank and/or the refueling water storage tank discharging to the reactor coolant system via the reactor vessel injection and/or cold leg injection lines. The high pressure safety injection system does not include the accumulator injection lines, the residual heat removal system nor the recirculation from the containment sump.
B.
Valve Selection 1.
Safety injection pump suction i
From boric acid storage tank (2 valves) a.
b.
From refueling water storage tank (2 valves)
Common pump suction (2 valves) c.
2.
Safety injection pump discharge to the reactor vessel.
Safety injection pump discharge to the cold leg valves are not considered in the evaluation because Technical Specifi-cations require these values to be open with their associated motor control center supply breakers locked open.
II.
AUXILIARY FEEDWATER SYSTEM A.
Definition 1.
Auxiliary feedwater pump suction from the condensate storage tanks and/or the cooling water system discharging to the steam generators.
2.
Steam supply from the steam generators to the turbine driven auxiliary feedwater pump.
B.
Valve Selection 1.
Auxiliary feedwater pump suction.
-From condensate storage tank (2 valves).
a.
b.
From cooling water system (2 valves).
2.
Auxiliary feedwater pump discharge to steam generator (4 valves). --
j
3.
Turbine driven auxiliary feedwater pump steam supply from the steam generators (2 valves).
III. VALVE DIFFERENTIAL PRESSURE DESIGN BASIS
. System parameter evaluation (maximum pressure producing A.
capability).
1.
Pumps Operating - maximum discharge head.
a.
E,
- Jut optisting.
2.
Relief valves - set pressure plus ASME allowable deviation.
3.-
Piping Elevation changes only considered with valves at th -
a.
low points of systems to increase the maximum differen-tial pressure.
b.
Piping line breaks downstream or upstream of valve.
4.
Check valves a.
Short term - no significant back leakage, b.
Long term - leakage across disc sufficient to equalize pressure on either side of disc.
5.
Tanks a.
Elevation Head b.
Design pressure 6.
Systems a.
Reactor coolant system design pressure b.-
Steam generator design pressure 7.
Valves Valves required to be locked open by Technical a.
Specifications are assumed to be in the correct position. i
= ~
b.
Class IE valve electrical interlocks are assumed to be operable.
Globe valves are evaluated using the elevated pressure c.
downstream of the valve in the close to open cycle and elevated pressure upstream of the valve in the open to close cycle. These assumptions preclude system pressure from assisting the actuator to open or close the valve and are considered to be very conservative.
B.
Evaluation Assumptions 1.
Per the guidance in item (a) of the bulletin, multiple valve mispositioning to cause an elevated AP across another valve was not considered in the evaluation.
2.
Multiple check valve back-leakage is possible to cause a AP across a closed upstream valve. Multiple check valve leakage cannot cause significant AP across an open upstream valve (i.e. - gross check valve leakage is not plausible).
3.
Valves not desired to be operable / opened against a AP higher than their design AP need only be operable at their design AP.
4.
Similarity of Unit 1 and Unit 2 piping (i.e. valve location, pump sizes, relief valve setting) does not warrant independent evaluations for each unit.
5.
Motor valves are evaluated in their safeguards actuation mode (s) and not for operations convenience modes. For example, the Safety Injection Pump suction from the RWST is not being evaluated when it is being used as a drainage path for the refueling cavity.
_3-i
TABLE 1 VALVE IDENTIFICATION AND DIFFERENTIAL PRESSURES IEB 85-03 EVAL ORIGINAL VALVE (S)
VALVE ACTUATOR FUNCTION AP (MAX)
DESIGN AP d
~ MF-32081-Limitorque SMB-00 Safety Injection 32h psi 200 psi 3550 rpm Pump (s) Suction MV-32082 from Boric Acid.
Storage Tank MV-32184 MV-32185 MV-32079 Limitorque SMB-0 Safety Injection 32 psi 100 psi 3550 rpm Pump (s) Suction from Refueling MV-32080 Water Storage Tank MV-32182 MV-32183 MV-32162 Limitorque SMB-00 Safety Injection 32h psi 200 psi 3550 rpm Pump (s) Suction MV-32163 MV-32190 MV-32191 MV-32074
.Limitorque, SMB-00 Reactor Safety 2510 psi 2750 psi 1700 rpm Injection MV-32177 Hot Leg Isolation MV-32172 Limitorque, SMB-00 Reactor Safety 2510 psi 2750 psi 1700 rpm Injection MV-32170 Hot Leg Isolation MV-32069 MV-32067 MV-32202 Limitorque, SMB-00
-Safety Injection 2287 psi 2750 psi J
1750 rpm Pump (s) Mini-j MV-32203 Flow Recirculation Valves MV-32204 MV-32205
=_
l-TABLE 1 VALVE IDENTIFICATION AND DIFFERENTIAL PRESSURES IEB 85-03 EVAL ORIGINAL VALVE (S)
VALVE ACTUATOR FUNCTION AP (MAX)
DESIGN AP j
.MV-32333 Rotork 14A-Condensats to 14 psi 25 psi Auxiliary Feedwater MV-32335 Pump Suction MV-32336 i
MV-32345 j
j MV-32025 Limitorque SMB-000 Cooling Water to 135 psi.
150 psi 1
1700 rpm Auxiliary Feedwat MV-32026 Pump Suction MV-32027 l
MV-32030 MU-32016 Limitorque SMB-00 Main Steam Supply 1086 psi 1100 psi 1700 rpm to Turbine Driven l
MV-32017 Auxiliary Feedwatar Pump MV-32019 I
MV-32020 MV-32238 Limitorque, SMB-00 Turbine Driven 1780 psi 1630 psi l
Auxiliary Feedwater MV-32239 Pump Discharge to Steam Generators MV-32246 MV-32247 MV-32381 Limitorque, SMB-000 Motor Driven 1780 psi 1630 psi 1700 rpm Auxiliary MV-32382 Feedwater Pump Discharge to Steam MV-32383 Generator MV-32384
- )
TABLE 2 IEB 85-03 MAXIMUM DIFFERENTIAL PRESSURE EVALUATION AND BASIS Close to Open/Open to Close VALVE (S) 85-03 EVAL AP BASIS MV-32081 23 /32h psi Elevation head of boric acid storage tank for closed to open. Elevation head of MV-32082 refueling water storage tank for open to closed.
MV-32184 MV-32185 MV-32079 32% psi Elevation head of refueling water storage tank for closed to open cg; open to closed.
MV-32080 MV-32182 MV-32183 MV-32162 32h psi Elevation head of refueling water storage tank for closed to open cg; open to closed.
MV-32163 High pressure on downstream side of valve is not possible due to interlock with Safety MV-32190 Injection Pump suction from RHR.
MV-32191 MV-32074 2510 psi Reactor coolant system safety valve set point plus 1 percent ASME tolerance for MV-32177 closed to open or open to closed (This AP is greater than the AP that would be developed if the safety injection pumps were taking suction from the RHR system).
MV-32172 2510/2465 psi Reactor coolant system safety valve set point plus 1 percent ASME tolerance MV-32170 for closed to open.
Safety injection pump shutoff head while taking suction a
MV-32069 from RHR at 210 psi for open to closed.
MV-32067
T
?
TABLE 2' IE3 85-03 MAXIMUM DIFFERENTIAL PRESSURE EVALUATION AND BASIS (CONT'D)
Close to Open/Open to Close VALVE (S) 85-03 EVAL AP BASIS MV-32202 2287h psi Safety injection pump shutoff head plus maximum elevation head of refueling MV-32203-water storage tank ior open to closed.
An elevated AP without pressure assisting-MV-32204 the motor actuator is not possible in the closed to open cycle. The downstream side MV-32205 of the valve is vented to atmosphere.
MV-32333 14 psi Elevation head of condensate storage tank.
MV-32335 MV-32336 MV-32345 MV-32025 135 psi-Cooling Water Pump shut off head MV-32026 MV-32027 MV-32030 MV-32016 1086 psi Lowest Main Steam Safety Valve
{
s joint plus 1 percent ASME tolerance MV-32017 t
MV-32019 t
MV-32020 MV-32238 1086/1780 psi Lowest Main Steam Safety Valve setpoint plus I percent ASME tolerance MV-32239 for closed to open. Auxilisry feedwater pump shutoff head plus MV-32246 suction pressure developed by cooling water pumps (nominal cooling MV-32247 water pump discharge pressure) for open to closed.
MV-32381 1086/1780 psi Lowest Main Steam Safety Valve setpoint plus 1 percent ASME MV-32382 tolerance for closed to open.
Auxiliary feedwater pump shutoff MV-32383 head plus suction pressure developed by cooling water pumps (nominal
- MV-32384 cooling water pump discharge pressure) for open to closed.
TABLE 3 IEB 85-03 MOTOR ACTUATOR / VALVE COMPLIANCE PROGRAM 1.
Motor valve opening and closing control modes, be it torque control or limit control, are to be reviewed.
Incorporated in this initial review will be a review of any control interlocks associated with the designated valves to assure any switch settings to be changed do not affect valve position indication or signals to other equipment.
(Review to be completed by October 1, 1986.)
2.
Documented existing switch settings and methods for setting the switc!.es will be reviewed and compared to existing manufacturer's recommendations. This review will encompass torque switches, tarque bypass switching, limit switches and thermal overloads.
(Review to be complete by October 1, 1986.)
3.
Using any new or revised methods for setting switches developed from item 2, above, existing plant procedures will be updated to reflect the new methodology.
(Procedure revisions to be completed by December 1, 1986.)
4.
Prior to changing any existing switch settings plant personnel will be trained on full scale operctional motor valves. Furthermore, the adequacy of the revised procedures will be demonstrated.
(Training and procedure verification will be completed by April 1, 1987.)
5.
The testing of the motor valvas will consist of:
a.
As found current and/or power traces.
b.
Switch resetting, if necessary.
c.
Differential pressure test at elevated pressures taking current and/or power traces.
d.
Test result reviews and motor valve operability declaration.
e.
Updating existing setpoint files.
Testing and resetting of any switches for motor operated valves will be performed during the spring, 1987 refueling outage for Unit 1.
Due to manpower limitations, the testing and resetting of the Unit 2 switches cannot be completed until the Unit 2 refueling outage currently scheduled for January, 1988. Based on this schedule, the Unit 2 program will exceed the completion date specified in Item (e) of the bulletin by appronimately three months.
J
r, 6.
~ The. valves previously identified will be incorporated into the scheduled preventive maintenance program. Maintenance, consisting of current / power trace, motor megger, actuator inspection, valve stem lubrication will be performed on each actuator every 5 years.
This maintenance will also verify siwitch settings. To further verify the switch settings are maintained, surveillance procedures will be developed. These procedures will inspect and verify correct settings.
7.
A final report, providing 1) verification of the completion of the motor valve program, 2) a summary of as found valve operability and
- 3) a summary of the data collected will be submitted within 60 days after completion of item 5 above.
9
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