ML19305E083
| ML19305E083 | |
| Person / Time | |
|---|---|
| Site: | Quad Cities  |
| Issue date: | 04/14/1980 |
| From: | Kalivianakis N COMMONWEALTH EDISON CO. |
| To: | Case E Office of Nuclear Reactor Regulation |
| References | |
| NJK-80-138, NUDOCS 8004220333 | |
| Download: ML19305E083 (5) | |
Text
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'~^N Commonw:alth Edison
'; O
) Quad Citi:s Nuct:ar Power Station I
v /, 22710 206 Av:nu3 North
/ Cordova,lilinois 61242 yNs' Telephone 309/654-2241 NJK-80-138 April 14, 1980 Mr. Edson G. Case, Deputy Director Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, D. C.
20555
Dear Mr. Case:
Enclosed please find a listing of those changes, tests, and experiments completed during the month of March, 1980, for Quad-Cities Station Units 1 and 2, DPR-29 and DPR-30. A summary of the safety evaluation is being reported in compli-
)
ance with 10 CFR 50.59 Thirty-nine copies are provided for your use.
Very truly yours, COMMONWEALTH EDIS0N COMPANY QUAD-CITIES NUCLEAR POWER STATION E
N. J. Kalivianakis Station Superintendent bb Enclosure cc R. F. Janecek i
I l
8004aar>333
H-4-2-79-16 Group 11 Primary Containment isolation Reset Circuit Description of Modification This modification involved changing the Group ll Primary Containment isolation reset circuitry such that the control switches for all of the applicable Group 11 valves must be in the closed position before the iso-lation signal can be reset. This modification will prevent automatic opening of these valves when the isolation signal is reset. This modifi-cation was installed per an NRC commitment (reference NUREG 0578).
Summary of Safety Evaluation The possibility of a different type of accident or malfunction than previously evaluated in the FSAR is reduced since automatic opening of the~
valves upon reset has been eliminated, thus avoiding accidental automatic valve opening.
M-4-2-79-22 Main Steam Relief and Safety Valves Position Indication Description of Modification Acoustic monitors were installed on the mischarge of the main steam relief and safety valves to sense the vibration produced by the steam dis-charge of each valve. This modification is expected to provide positive open/ closed position indication for each valve Instead of determining the valve posi tion f rom other parameters.
This modification was installed based on an NRC commitment (reference NUREG 0578).
Summary of Safety Evaluation The FSAR related function of the valves is not changed by these modifications.
The probability of an accident decreases because this system allows the operator to know the position of the valves.
The margin of safety as defined in the basis for the Technical Specifications is in-creased because-the system is designed to detect fluid flow through the valves.
H-4-2-79-28 Containment Vent and Purge Butterfly Valves Description of Hodification This modification was.to Install mechanical stops on the drywell and suppression chamber vent and purge butterfly valves so as to restrict their opening travel to 40 degrees. This modification was initiated based on an NRC commitment.
Summary of Safety Evaluation g
The FSAR related isolation and purging function of these valves is not chang'ed by these nodifications, and by limiting the' opening angle of the valves, the margin of performance of the isolation function is increased.
M-4-2-78-16 Diesel Generator Auto-Start Test Switches f
Description of Modification p
This modification installed a test switch in both the Unit One and the One/Two diesel generator auto-start ci rcui ts.
The test switches were in-stalled between the main feed air circuit breaker contact and the automatic start relay of the respective diesel generator. The test switches will be used during surveillance testing of the diesels to verify that the diesels auto-start from bus undervoltage relay operation rather than from the breaker actuation. The test switches will be. In the closed position for normal plant operation, and will be opened only during surveillance testing.
Summary of Safety Evaluation The installation of the test switches will not change the operation of the system as previously evaluated. The emergency diesel generators will maintain the same standby function and installation of the test switches does not alter the overall safety of the system. The Technical Specifica-tion requirements concerning the system will remain unchanged.
4 S
1 M-4-2-77-3 Suppression Chamber Drain Line Description of Modification A two inch drain line was installed on the suppression chamber drain header penetration X-213A.
This drain line is intended to provide a method for draining the suppression chamber when the water level is below the emergency core cooIIng system suction header. The drain line is fitted with two isolation valves which are locked closed when the drain line is not in use.
Summary of Safety Evaluation A hydrostatic test of the newly installed drain 11ne assures system integrity and the use of redundant locked closed isolation valves and screwed pipe caps should be sufficient insurance against developement of a major torus water leak for lines of this size.
Consequently, margins of
[
safety are not reduced as a result of this modification.
i i
J H-4-2-77-29 1
Core Spray Pump Discharge Relief Valves f
l Description of Modificatign The spring assemblies in the. core spray pump discharge relief valves' (2-1402-28A & 28B) was changed to raise the setpoint to 475 psig from the -
previous setting of 375 psig. This setpoint change is intended to prevent lif ting of the relief valves when the system is pumping through the minimum flow line, thereby reducing the possibility of overflowing the reactor building equipment drain tank. The new setpoint is five percent below the maxinium allowable relief setpoint of 500 psig.
' Summary of Safety Evaluation The only change to the system is to'the relief valve's setpoints.
The new setpoints meet all applicable code requirements, and will help prevent malfunctions by increasing the margin between operating pressure and relief valve setpoints. Therefore, the consequences of a previously i
evaluated accident is not changed, nor is the possibility of a different type of accident or malfunction increased, f
I m
i s
H-4-2-74-35 RHRS Service Water Isolation Valves Description of Modification This modification involved installation of manually operated butter-fly valves downstream of the 2-1001-5A and SB Residual Heat Removal System (RHRS) service water valves. The new valves will be used as isolation valves to permit maintenance on either the 2-1001-5A or 5B valves without draining the complete RHRS service water discharge header. The new valves will be locked open during normal system operation.
Summary of Safety Evaluation The new valves were installed in accordance with the original design requirements and will be locked open during normal plant operation.
Since the valves are passive components, the possibility of a different type of accident or malfunction is not created. The function of all other components in the RHR service water system will be unchanged.
In the modification summary reported for February, 1980, the summary for the drywell mechanical snubber modification was incorrectly I
reported as M-4-1-77-36.
It should have been reported as M-4-2-77-36,
~
Indicating a Unit Two modification instead of Unit One.
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