ML20207Q474
| ML20207Q474 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 01/16/1987 |
| From: | VERMONT YANKEE NUCLEAR POWER CORP. |
| To: | |
| Shared Package | |
| ML20207Q468 | List: |
| References | |
| NUDOCS 8701270405 | |
| Download: ML20207Q474 (5) | |
Text
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I VYNPS 3.4 LIMITING CONDITIONS FOR OPERATION 4.4 SURVEILIANCE REQUIREMENTS 3.4 REACTOR STANDBY LIQUID CONTROL SYSTEM 4.4 REACTOR STANDBY: LIQUID CONTROL SYSTEM Applicability Applicability Applies to the operating status of the Reactor Applies to the periodic testing requirements for Standby Liquid Control System.
the Reactor Standby Liquid Control System.
Objective Objective To assure the availability of an independent To verify the operability of the Standby Liquid reactivity control mechanism.
Control System.
Specification Specification A.
Normal Operation A.
Normal Operation Except as specified in 3.4.B below, the At least monthly, the Standby Liquid Control Standby Liquid Control System shall be System shall be verified operable by:
operable during periods when fuel is in the l
reactor unless:
1.
Operating each pump and recirculating demineralized water to the test tank. A l
1.
The reactor is in cold shutdown minimum flow rate of 35 spa at 1275 psig l
shall be verified for each pump.
aM 2.
Verifying the continuity of the 2.
Control rods are fully inserted and explosive charges.
Specification 3.3.A is met.
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At least once during each operating cycle, the Standby Liquid Control System shall be verified operable by:
87 127 l
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Amendment No.
79 t
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VYNPS i
3.4 LIMITING CONDITIONS FOR OPERATION 4.4 SURVEILIANCE REQUIREMENTS 1
I 1.
Testing that the setting of the pressure relief valves is between 1400 and 1490 psig.
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2.
Initiating one of the standby liquid control loops, excluding the primer
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chenber and inlet fitting, and verifying that a flow. path from a pump to the reactor vessel is available by pumping domineralized water into the reactor-vessel. Both loops shall be tested over the course of two operating cycles.
3.
Testing the new trigger assemblies by installing one of the assemblies.in the test block and firing it using the installed circuitry.
Install the l
unfired assemblies, taken from the same i
I batch as the fired one, into the explosion valves.
4.
Recirculating the borated solution.
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Amendment No.
1 79a.
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VYNPS I
3.4 LIMITING CONDITIONS FOR OPERATION 4.4 SURVEILLANCE REQUIREMENTS B.
Operation With Inoperable Components B.
Operation With Inoperable Components I
From and after the date that a redundant component When a component becomes inoperable, its redundant is made or found to be inoperable, reactor component shall be demonstrated to be operable operation is permissible during the succeeding immediately and daily thereafter.
seven days unless such component is sooner made operable.
C.
Liquid Poison Tank - Baron Concentration C.
Liquid Poison Tank - Boron Concentration At all times when the Standby Liquid Control 1.
The solution volume in the tank and System is required to be operable, the following temperature in the tank and suction piping conditions shall be met:
shall be checked at least daily.
I 1.
The net volume versus concentration of the 2.
Sodium pentaborate concentration shall be sodium pentaborate solution in the standby determined at least once a month and within liquid control tank shall meet the requirements of Figure 3.4.1.
24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> following the addition of water or boron,aor if the solution temperature drops below the limits specified by Figure 3.4.2.
1 2.
The solution temperature, including that in i
the pump suction piping, shall be maintained above the curve shown in Figure 3.4.2.
i D.
If Specification 3.4.A or B is not met, an orderly shutdown shall be initiated and the reactor shall i
be in the cold shutdown condition within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
l E.
If Specification 3.4.C is not met, action shall be i
immediately initiated to correct the deficiency.
If at the end of 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> the system has not been restored to full operability, then a shutdown shall be initiated with the reactor in cold shutdown within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of initial discovery.
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Amendment No. 75, 78 80
VYNPS Bares:
3.4 & 4.4 REACTOR STANDBY LIQUID CONTROL SYSTEM A.
Normal Operation The design objective of the Reactor Standby Liquid Control System is to provide the capability of bringing the reactor from full power to a cold, xenon-free shutdown assuming that none of the withdrawn control rods can be inserted. To meet this objective, the Liquid Control System is designed to inject a quantity of boron which produces a concentration of 800 ppm of boron in the reactor core in less than 138 minutes. An 800 ppm boron concentration in the reactor core is required to bring the reactor from full power to a 5% Ak subcritical condition. An additional margin (25% of boron) is added for possible. imperfect mixing of the chemical solution in the reactor water. A minimum quantity of 3850 gallons of solution having a 10.1% sodium pentaborate concentration is required to meet this shutdown requirement.
The time requirenent (138 minutes) for insertion of the boron solution was selected to override the rate of reactivity insertion due to cooldown of the reactor following the xenon poison peak. For.a required minimum pumping rate of 35 gallons per minute, the maximum net storage volume of the boron solution is established as 4830 gallons.
4 Boron concentration, solution temperature, and volume are checked on a frequency to assure a high reliability of 1
operation of the system should it ever be required. Experience with pump operability indicates that testing at j
monthly intervals is adequate to detect if failures have occurred. Flow, relief valve, circuitry, and trigger assembly testing at the prescribed intervals assures a high re'iability of system operation capability.
Recirculation of the borated solution is done during each operating cycle to ensure one suction line from the i
boron tank is clear.
i B.
Operation With Inoperable Components Only one of the two standby liquid control pumping circuits is needed for proper operation of the system.
If one pumping circuit is found to be inoperable, there is no immediate threat to shutdown capability, and reactor 4
operation may continue while repairs are being made. Assurance that the remaining system will perform its 2
intended function, and that the reliability.of the system is good, is obtained by demonstrating operation of the i
pump in the operable circuit at least once daily.
C.
Liquid Poison Tank - Boron Concentration The solution saturation temperature varies with the concentration of sodium pentaborate. The solution shall be kept at least 100F above the saturation temperature to guard against boron precipitation. The 100F margin is included in Figure 3.8.3 of the FSAR. Temperature and liquid level alarms for the system are annunciated in j
the Control Room.
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Amendment No.
83
VYNPS 3.4 & 4.4 REACTOR STANDBY LIQUID CONTROL SYSTEM Pump operability la checked at a frequency to assure a high reliability of operation of the system should it ever be required.
Once the solution has been made up, boron concentration will not vary unless more boron or more water is added.
Level indication and alarm indicate whether the solution volume has changed which might indicate a possible solution concentration change. Considering these factors, the test interval has been established.
Sodium pentaborate concentration is determined within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> following the addition of water or boron, or if the solution temperature drops below specified limits. The 24-hour limit allows for 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> of mixing, subsequent testing, and notification of shift.
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Amendment No.
g4