ML20080F716
| ML20080F716 | |
| Person / Time | |
|---|---|
| Site: | Cooper  |
| Issue date: | 01/24/1995 |
| From: | Mueller J NEBRASKA PUBLIC POWER DISTRICT |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NLS940145, NUDOCS 9501300201 | |
| Download: ML20080F716 (7) | |
Text
..
Nebraska Public Power District
" " #59555!$$$f3f55[""
NLS940145 January 24,1995 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555
Subject:
Inservice Testing Program Relief Requests Cooper Nuclear Station NRC Docket No. 50-298, License No. DPR-46 Gentlemen:
Attached for yaur review and approval are Relief Requests RV-63, RV-64, RV-65, and RV-66 to the Cooper Nuclear Station (CNS) Inservice Testing (IST) program. The Nebraska Public Power District (the District) is submitting these relief requests in accordance with the requirements of 10 CFR 50.55a(f)(5)(iii) and 50.55a(f)(5)(iv). The District asks that these relief requesti, once granted, become effective immediately, and remain in effect through the second ten year IST interval, which concludes subsequent to the conclusion of the next scheduled refueling outage.
Should you have any quesuons or require additional information regarding these requests, please call.
2 Sincerely, l
I /J)n A J hn 11. Mueller i
Site Manager
/dnm Attachment I
cc:
Regional Office USNRC Region IV NRC Resident Inspector Cooper Nuclear Station NPG Distribution Fl0101 3(
9501300201 950124 DR ADOCK 05000298 PDR
Attachment to NLS940145 Page 1 of 5 RELIEF REQUEST RV-63 VALVE (s):
NBI CV-49BCV NBI-CV-50BCV NBI-CV-51BCV NBI-C7-52BCV NBI-SOV-SSV738 NBI-SOV-SSV739 CLASS:
3 FUNCTION:
The reference leg injection check valves and solenoid operated valves have an active safety function in the open position to inject CS water to the reactor vessel level instrumentation lines in case the reference leg water has flashed or boiled off due to accident conditions in the drywell.
REQUIRED TEST:
Check valves shall be exercised at least once every 3 months, or during 1
cold shutdown periods in accordance with the requirements ofIWV-3521 and IWV-3522.
Power operated vnives shall be exercised at least once every 3 months, or during cold shutdown periods in accordance with the requirements of IWV-3411 and IWV-3512.
BASIS FOR RELIEF:
This system provides the capability for the Core Spray System to supply a backfill of water for maintaining inventory of the Nuclear Boiler Instrumentation System cold reference legs (condensing chambers 3A and 3B) during accident conditions in the drywell where the reference leg inventory could be compromised. Exercising these valves to the open l
position, full or partial, would require manually isolating and venting the Cold Reference Leg Backfdl System. This is not practicable during power operation or cold shutdown, other than refueling, due to the possible introduction of air into the system. This could cause a spurious reactor vessel level indication which could cause a reactor trip during power operation. During cold shutdown spurious level indications could interrupt the operation of systems required for decay heat removal, thereby placing the reactor in an unsafe condition. During refueling i
outages, sufficient time exists for decay heat to be reduced to a level which minimizes the imliact of momentary interruption in the operation t
l of systems required for decay heat removal such that testing can be performed.
l ALTERNATIVE TEST:
Exercising these check valves to the full open position, and full exercising with stroke timing to the open position of the solenoid operated valves, shall be performed during each refueling outage.
i l
1 Attachment to NLS940145 Page 2 of 5 RELIEF REQUEST RV-64 VALVE (s):
NBI-CV-55CV NBI-CV-56CV CLASS:
3 FUNCTION:
These Cold Reference Leg Continuous Backfill System check valves have an active safety function in the closed position to isolate the Class 3 instrumentation piping from the Seismic IIS non-class CRD piping.
REQUIRED TEST:
Check valves shall be exercised at least once every 3 months, er during cold shutdown periods in accordance with the requirements ofIWV-3521 and IWV-3522.
BASIS FOR RELIEF:
This system provides for a continuous flow of water from the CRD drive water pumps to prevent noncondensable gases from building up in the Nuclear Boiler Instrumentation System cold reference legs (condensing chambers 3A and 3B). Exercising these valves to the closed position would require manually isolating and venting of the Cold Reference Leg Continuous Backfill System upstream of the check valves. This is not practicable during power operation or cold shutdown, other than refueling, due to the possibility of causing a spurious reactor vessel level indication from entrained air in the system.
False level indications resulting from entrained air in the system may either cause a reactor trip during power operation or interrupt the operation of systems required during cold shutdown for decay heat removal, thereby placing the reactor in an unsafe condition. During refueling outages, sufficient time exists for decay heat to be reduced to a level which minimizes the impact of l
momentary interruption in the operation of systems required for decay heat removal such that testing can be performed.
ALTERNATIVE TEST:
Exercising these check valves to the closed position shall be performed during each refueling outage. Exercise testing shall be accomplished by performing a Section XI seat leakage test.
1
=
Attachment to l
NLS940145 Page 3 of 5 RELIEF REQUEST ltV-65
(
VALVE (s):
IIPCI-SOV-SSV64 and IIPCI-SOV-SSV87 CLASS:
2 FUNCTION:
The llPCI turbine and exhaust steam drip leg drain to gland condenser (IIPCI-SOV-SSV64) and IIPCI turbine and exhaust steam drip leg drain to equipment drain isolation valve (ilPCI-SOV-SSV87) have an active safety function in the closed position to maintain pressure boundary integrity of the llPCI turbine exhaust line. These valves serve as a Class 2 to Non-Code boundary barrier.
REQUIRED TEST:
Full exercise and stroke time to the closed position at least once each quarter in accordance with the requirements of IWV-3411, IWV-3412, and IWV-3413.
When practicable, valves with fail-safe actuators shall be tested by observing the operation of the valves upon loss of actuator power in accordance with the requirements ofIWV-3415.
BASIS FOR RELIEF:
These valves are rapid acting encapsulated solenoid operated valves.
Their control circuitry is provided with a remote manual switch for valve actuation to the Open position and an Auto function which allows the valves to actuate from signals received from the associated level switches llPCI-LS-98 and LS-680. Both valves receive a signal to change disc position during operability testing of drain pot level switches. Ilowever, remote position indication is not provided for positive verification of disc position. Additionally, their design prohibits the ability to visually verify the physical position of the operator, stem or internal components.
Modification of the system to verify valve closure capability and stroke timing is not practicable nor cost beneficial since no commensurate increase in safety would be derived.
ALTERNATIVE TEST:
These solenoid valves shall be disassembled and inspected each refueling outage.
kEdi2Mb
Attachment to
~
NLS940145 Page 4 of 5 RELIEF REQUEST RV-66 VALVE:
IIPCI-AOV-PCV50 CLASS:
2 FUNCTION:
Air operated, pressure regulating valve f.
he cooling water supply line to the llPCI lube oil cooler.
The valve performs an active safety function in the open/ throttled position to allow cooling water flow to the lube oil cooler.
REQUIRED TEST:
Category Il valves shall be exercised and stroke timed at least once every three months in accordance with the requirements of IWV-3412, IWV-3413, and IWV-3415.
As a valve that responds to system conditions, this valve would normally be exempt from IST requiremerts as permitted by IWV-1200(a);
however, the valve is required to be tested in accordance with the requirements ofIWV-3400 because it has a fail-safe position. (GL 89-04,, Position 11) llASIS FOR RELIEF:
This valve functions to control pressure in the cooling water supply line to the IIPCI turbine lube oil cccler. Cooling water is supplied from the IIPCI booster pump discharge. The valve is normally maintained in the closed position as a result of the IIPCI pump being idle and pressure maintenance, supplied by the auxiliary condensate system, maintaining the IIPCI piping water solid.
A pressure controller provides a signal to close the valve, thereby limiting the lube oil cooler inlet cooling water pressure to s 75 psia. The valve travels to a throttled position, when the 11PCI pump starts, to automatically maintain pressure in the cooling water line at 50 psig. The valve's control circuitry prevents disk travel from the full-closed position to the full-open position. System design prevents overpressurization of the downstream piping and components in the event that the valve fails to the open position since a relief valve is installed to prevent this occurrence. As a further design enhancement, restricting orifices are installed both upstream and downstream of the valve to limit flow and reduce pressure.
The valve is designed to fail to the open position on a loss ofinstrument air or electrical control power to ensure continuity of cooling water flow l
to the lube oil cooler.
l i
I l
Attachment to NLS940145 Page 5 of 5 Stroke timing this control valve is impractical due to the design of the valve. Repeatable stroke times are not attainable because the valve is not equipped with remote position indicators or control switches and because the normal position of the valve varies based on system requirements.
Full-stroke exercising is impractical because the valve is not designed to go from full-closed to the full-open position. Compliance with Code stroke timing and full-stroke exercising requirements would require system modification such as replacement of the control valve and control system redesign. These modifications necessary to achieve full valve J
closure, would be burdensome and not offer any commensurate increase in safety with cost benefit.
j ALTERNATIVE TEST:
Lube oil temperatures and bearing temperatures will be monitored during system operation for indications of pressure control _ valve degradation.
Additionally, this control valve will be verified to travel from its normal throttled position to the open fail-safe position when the HPCI pump is retumed to the standby condition, prior to closure of the llPCI test loop return isolation valves. Closure of these test loop isolation valves re-establishes pressure maintenance.
1 i
t-m e
f LIST OF NRC COMMITMENTS l ATTACHMENT 3 l Correspondence No: N1,S940145 l
The following table identifies those actions committed to by the District in this document. Any other actions j
discussed in the submittal represent intended or planned actions by the District. They are described to the NRC for the NRC's information and are not regulatory commitments. Please notify the Licensing Manager at Cooper Nuclear Station of any questions regarding this document or any associated regulatory commitments.
COMMITTED DATE COMMITMENT OR OUTAGE RV 63: Exercise Check Valves NBI-CV-49BCV, 50BCV,51BCV, and 52BCV During each refueling outage to the full open position.
RV-63: Full exercise Solenoid Operated Valves NBI-SOV-SSV738 and 739 with During each refueling outage stroke timing to the open position.
RV-64: Exercise Check Valves NBI-CV-55CV and 56CV to the closed position.
During each refueling outage Exercise testing shall be accomplished by perfonning a Section XI seat leakage test.
RV-65: Disassemble and inspect Check Valves llPCI-SOV-SSV64 and llPCI-During each refueling outage SOV-SSV87.
RV-66: Lube oil temperatures and bearing temperatures will be monitored for ilPCI during system operation for indications of pressure control valve degradation. Additionally, Control Valve llPCI AOV-PCV50 will be verified to During system operations travel from its normal throttled position to the open fail-safe position when the llPCI pump is returned to the standby condition, prior to closure of the llPCI test loop return isolation valves.
l PROCEDURE NUMBER 0.42 l
REVISION NUMBER 0 l
PAGE 10 OF 16 l