ML20207G655
| ML20207G655 | |
| Person / Time | |
|---|---|
| Site: | Quad Cities  |
| Issue date: | 07/27/1988 |
| From: | Robey R COMMONWEALTH EDISON CO. |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8808240191 | |
| Download: ML20207G655 (11) | |
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Commonwealth Edison t
ouad Cities Nuclear Power Station 22710 206 Avenue North a
Cordova, Illinois 61242 Telephone 309/654 2241
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RAR-88-3B 1
July 27, 1988 Director of Nuclear Reactor Regulat.wns U. S. Nuclear Regulatory Commission Mail Station P1-137 Washington, D. C.
20555 Enclosed please find a listing of those changes, tests, and experiments completed during the nonth of July,1988, for Quad-Cities Station Units 1 and 2, DPR-29 and DPR-30.
A summary of the safety evaluation is being reported in compliance with 10 CFR 50.59.
Thirty-nine copies are provided for your use.
Respectfully, COMMONHEALTH EDISON COMPANY j
QUAD-CITIES NUCLEAR POWER STATION A.09 R. A. Rob *y Services Superintendent RAR/vmk Enclosure cc:
I. Johnson T. Watts /J. Galligan 1
3 0027H/0061Z 8808240191 880727 PDR ADOCK 05000254 R
Modification M-4-)-84-13 Description This modification was to install a one-hour rated fire wrap on the Unit 2 480V alternate feed to the 1/2 D.G. Cooling Water Pump.
The modification insures the availability of the pump in the event of a fire in zone TB-1.
This will comply with 3M's fire wrap installation procedure, existing conduits supports are to be relocated. The relocation will prevent the need to wrap the cable pan curr ently connected to the supports.
This is required if the length of a suppert connected to wrapped conduit is less than 18 inches.
Evaluation The modification does not interfere with any existing safety related systems or equipment.
The equipment effected will perform the same functions previous to the modification, so there is no safety concern.
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Modificat on M-4-1-85-25 Description M-4-1-85-25 modified several pipe restraints on the heat traced lines of the Containment Atmospheric Monitoring (CAM) system and installed con-tainment isolation check valves 1-2499-22A and 1-2499-22B on the return lines.
When the CAM system was upgraded, heat tracing was placed on the instrument lines. The heat tracing causes the instrument lines to expand. A reanalysis of these lines has shown that high stresses exist. A number of supports must be modified, added, or removed to solve the problem.
The containment isolation valves were to be installed during the upgrade of the CAM system, but were not due to procurement. They are being installed under this modification, i
Evaluation This modification does not change the function or limiting condition of operation for any safety system needed to mitigate the consequences of an accident.
This modification will improve the integrity of the sample a
lines and therefore reduces the probability of an occurrence or the con-sequences of an accident.
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Modification M-4-1-85-42 Description This modification is being made to satisfy the third and final requirement of 10 CFR 50.62 for the reduction of risk from an ATWS. The modification consists of providing a second pump suctiot. line from the SBLC tank to the common suction header, modifying the SBLC tank to provide a nozzle for the suction piping, and modifying the controls to provide for running both pumps simultaneously.
The existing SBLC control switch is a three position switch (SYS 1, OFF, and SYS 2).
Th2 existing control switch is being replaced by a fiva position switch (SYS 1 & 2, SYS 1, OFF, SYS 2, and SYS 2 & 1).
The SBLC pump discharge relief valves will be set to lift between 1455 and 1545 psig. The new SBLC pump suction line will be heat tra.md, will have an isolation valve, and will have a high/ low temperature switch that will annunciate in the Control Room.
Evaluation This modification simply implements an additional performance objective of providing the capability to deliver 80 g.p.m. of 14% (minimum) sodium pentaborate solution in order to control, mitigate, and terminate certain anticipated transien.s with a concurrent failure of the reactor to scram (ATWS events).
The suction piping has been designed to ass'ae two pump NPSH and to eliminace concerns of mutually reinforcing puleations aJoociated with two pump operation.
Control logic and power separation is naintained between the two injection pumps and squib valves.
Pump discharge relief valve setpoints were increased to assure reliable system operation with two pumps running. Concern over sodium pentaborate crystallization due to increased concentration has been evaluated and low temperature alarm setpoint was changed to 78'F.
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Modification M-4-1-86-31 Description Modification M-4-1-86-31 was performed to restore the ACAD system, as a result of a reilroad boxcar collision with line 1-2501A on June 13, 1986.
As a result of this event several supports were deformed and the affected section of the ACAD line displaced.
The modificatior, work consisted of replacing supports, and upgrading sections if necessary. No modification to the actual piping was performed.
Evaluation This modification will restore the integrity of the damaged ACAD line supports and return the system to its design condition. The reanalysis and modification will not increase the probability of an accident. The modification will not affict the operation of the ACAD system, and thus has no potential for creating a new accident scenario. The margias of safety as defined in the Technical Specifications is based on the ability of.sa system to operate during postulated accidents. This modification does not change the function or limiting condition of operation for any safety system needed to mitigate the consequences of an accident.
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Modification M-4-2-85-42 i
Description j
This modification is being made to satisfy the third and finel reguirement
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of 10 CFR 50.62 for the reduction of risk from an ATWS. The modification l
consists c' providing a second pump suction line fron the SBLC tank to the common suctlar header, modifying the SBLC tank to provide a nozzle for the suction pir. 1, and modifying the co-trola to provide for running both pumps simu A t an',oL41 /.
The existing SBLC control switch is a three position switch (SYS 1. OFF.
and SYS 2).
The existing control switch is being replaced by a five position switch (SYS 1 & 2 SYS 1, OFF, SYS 2, and SYS 2 5 1).
The SBLC pump discharge relief valves will be set to lift between 1455 and 1545 psig. The new SBLC pump enction line will be heat traced, will have an isolation valve, and will have a high/ low temperature switch that will annunciate in the Control Room.
Evaluation This modification simply implements an additional performance objectivo of providing the capability to deliver 80 g.p.m. of 14' (minimum) sodium pentaborate solution in order to control, mitigate, and terminate in anticipated transients with a concurrent failure of the reactor t a (A1VS events).
The suction piping has been designed to assure two pump NPSH and to eliminate concerns of mutually reinforcing pulsations associated with two pump operation.
Control logic and power separation is maintained betwaen the two injection pumps and squib valves. Pump discharge relief valve setpoints were increased to assure relieble system operation with two pumps running. Concern over sodium pentaborate crystallization due to increased concentration has been j
evaluated and low temperature alarm setpoint was changed to 78'F.
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Modification M-4-2-86-10 Deucription This modification removed the RACR 1 relay with a RACR IV relay. This relay is only used while the diesel is in test. Minor wiring changes associated with the RACR relays were implemented, such as using the cabinet ground, installing safety-related crimps, wire and lugs. This modification was initiated due to system operational analysis recommendations and to improve system reliabiltiy.
Evaluation The RACR IV relay is essentially an improved RACR 1 relay.
The relay also has a voltage sensor, hence the V, but in essence performs in the same manner as the RACR 1 did. Wiring was upgraded and has no r.egative impact on safety.
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F Modification M-4-2-86-22 e
Description This modification replaced two electro-mechanical timers with one solid state agastat time delay relay per division on the Core Spray system. The time delay relay is used to sequentially load the Coro Spray pump to the bus in the event of a Core Spray initiation and loss of offsite power.
The electro-mechanical timers were less reliable and erratic in time. They were required to return to an "AT HOME POSIT 0N" to be ready for the next statt.
On occasions, they would not return to the "AT HOME POSITION".
Be:ause the new Agastat relay was more reliable and did not require an "AT HOME POSIT 0N" alarm, the two electro-mechanical timers were replaced with one solid state relay.
Evaluation The now time delay relay perform the same function as the two electro-mechanical timers except for the "AT HOME POSITION" annunciator.
By removing the redundancy of two electe.-mechanical timers and replacing them with one solid state time delay relay, the possibility of creating a malfunction is not increased because of the reliability of the new time delay relays.
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Modification M-4-2-87-71 Description The purpose of this modification is to add vibration isolator assemblies to the Main Steam Line Low pressure switches 2-261-30A,B C,D located on instrument rack 2252-1.
Installation of the isolators will help to eliminate spurious activation of the switches due to excessive vibration at the switch mounting. The switch will be mounted on a plate. Another plate is mounted to the instrument rack, and the vibration isolators are sandwiched between the plates.
The conduit and tubing attached to the switch are replaced with more flexible types to isolate the switch.
Evaluation This modification does not change the switch performance requirements or function and therefore does not affect the margin of safety used for the l
basis of any technical specification. The limiting safety system settings are not changed as a result of this modification, and the low pressure isolations of the main steam lines at 850 psig minimum will still protect against rapid reactor depressurization and the resulting rapid cooldown of the vessel.
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e Modificatior. M-4-1(2)-84-33 i
Description The objective of this modification is to replace the G.E. CR2820 time delay relays with a more reliable Agastat time delay relay. The CR2820 relays are being replaced because they lose their accuracy when sitting for more than a month in the de-energized state. The new Agastat relays are solid state as compared to the old CR2820 relays which are oil dashpot types.
Because of their solid state design, the Agastat relaya will maintain a high degree of accuracy in spite of large bus voltage fluctuations or long periods of de-energization. The new Agastat relays replaced the CR2820 relays on a one-for-one basis.
Evaluation Ey improving the reliability of the time delay, the Agastat relays will increase the safety margin of the HPCI and RCIC systems.
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Modification M-4-1(2)-87-072 Description 1
On a routine inspection, it was discovered that supports for the ATWS instrument sensing lines near the 2201(2)-5 and 6 racks were not properly installed per ASME section III design requirements. Modification M04-1(2)-
i 87-072 was initiated as a corrective action. The modification consisted of installing seismic, safety-related supports to the sensing line in order to satisfy FSAR requirements.
Evaluation This modification will in no way increase the consequences or probability of an accident. The addition of the pipe supports will increase the strength of the sensing lines, making the system more reliable.
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