ML20101E462

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Proposed Tech Spec Changes Re post-accident Instrumentation
ML20101E462
Person / Time
Site: Vermont Yankee Entergy icon.png
Issue date: 12/14/1984
From:
VERMONT YANKEE NUCLEAR POWER CORP.
To:
Shared Package
ML20101E443 List:
References
RTR-NUREG-0737, RTR-NUREG-737 NUDOCS 8412260260
Download: ML20101E462 (9)
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3.2-' LIMITING CONDITIONS FOR OPERATION 4.2 SURVEILLANCE: REQUIREMENTS:

3.2 PROTECTIVE INSTRUNENT SYSTEMS 4.2 PROTECTIVE INSTRUMENT SYSTEMS J

i Specification (cont'd) Specification (cont'd) i I. Recirculation Pump Trio Instrumentation I. Recirculation Pum9 Trio Instrumentation

During reactor power operation, the The Recirculation Pump Trip Instrumentation l Recirculation Pump Trip Instrumentation shall shall be functionally' tested and calibrated in accordance with Table 4.2.1.

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j be operative in accordance with Table 3.2.1.

4 J. Control Room Toxic Gas Monitoring J. Control Room Toxic Cas Monitoring L' Whenever the Control Room is required to be The Toxic Gas Monitoring System manned, the Toxic Gas Monitoring-System shall Instrumentation shall be calibrated in be operable in accordance with Table 3.2.7. accordance with-Table 4.2.7.

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34a Amendment No. 58

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8412260260 841214 PDR ADOCK 05000271 P , PDR _ _-

VYNPS TABLE 3.2.6 POST-ACCIDENT INSTRUMENTATION

, Minimum Number of Opscable Instrument Instrument Channels Parameter Type of Indication Range 2 Drywell Atmospheric Temperature Recorder #16-19 0-3000F (Note 1) Recorder #TR-1-149 0-3000F 2 Containment Pressure (Note 1) Meter 16-19-29A 0-275 psia Meter 16-19-29B 0-275 psia

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1 Torus Pressure (Note 1) Recorder #16-19-44 0-80 psia 2 Torus Water Level (Note 3) Meter #16-19-10A 0-20 ft.

Meter #16-19-10B 0-20 ft.

2 Torus Water Temperature (Note 1) Meter #16-19-48 60-1800 F 2 Reactor Pressure (Note 1) Meter #PI-2-3-56A 0-1500 psig Meter #PI-2-3-56B 0-1500 psig 2 Reactor Vessel Water Level Meter #2-3-91A (-150)-0-(+150)"H 2O (Note 1) Meter #2-3-91B (-150)-0-(+150)"H 2O 1 Control Rod Position (Notes 1,2) Meter 0-48" RPIS 1 Neutron Monitor (Notes 1,2) Meter 0-125% Rated flux 1 Torus Air Temperature (Note 1) Recorder #TR-16-19-45 0-3000F 2/ valve Safety / Relief Valve Position Lights (SRV 2-71-A thru D) Closed - Open From Pressure Switches (Note 4) ,

49 Amendment No. 63

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VYNPS TABLE 3.2.6 POST-ACCIDENT INSTRUMENTATION (continued)

Minimum Number of Op r:ble Instrument Instrument Channels Parameter Type of Indication- Range 1/ valve Safety Valve Position From Meter 21-2-1A/B Closed - Open Acoustic Monitor (Note 5) 2 Containment Hydrogen /0xygen Meter SR-VG-6A 0-30% hydrogen Monitor (Note 1) Meter SR-VG-6B 0-25% oxygen 2 Containment High-Range Radiation Meter RM-16 1 R/he-10 7 R/hr Monitor (Hote 6) 1A/B Amendment No. 63 49a

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TABLE 3.2.6~

POST-ACCIDENT INSTRUNENTATION (continued)

TABLE 3.2.6 NOTES Note 1-FromandafterthedatethataparameterisnotindicatedintheControlRoom,continuedreactoroperationis-l.

' permissible during the next seven. days. If reduced to one indication of a parameter operation is permissible-for 30 days.

Cote 2 - Control rod position and neutron _ monitor instruments are considered to be redundant to each other. "

Cote 3 - From and after the date that this parameter is reduced to one indication in the Control Room.-continued j

, reactor operation is permissible during the next 30 days. If both channels are inoperable and indication l cannot be restored in six hours, an orderly shutdown shall be initiated and the reactor shall be in a" hot shutdown condition in six hours and a cold shutdown condition in the following 18 hours2.083333e-4 days <br />0.005 hours <br />2.97619e-5 weeks <br />6.849e-6 months <br />.

l Cote 4 - From and after the date that safety / relief valve positi from pressure switches is unavailable, reactor .

I operation may continue provided safety / relief valve po M. ion can be determined from recorder 2-166  !

l (thermocouple. 0-6000F) and meter 16-19-48 (torus waL. temperature, 60-1800 F). If both indications are l not available, the reactor shall be in a hot shutdown condition in six hours and a cold shutdown condition in. .;

j the following 18 hours2.083333e-4 days <br />0.005 hours <br />2.97619e-5 weeks <br />6.849e-6 months <br />.

i Note 5 - From and after the date that safety valve position from the acoustic monitor is unavailable, reactor l operation may continue provided safety valve position can be determined from recorder 2-166 (thersocouple,  !

I 0-6000 F and Metee 16-19-29A or B (containment pressure 0-275 psia). If both indications are not available,  !

the reactor shall be in a hot shutdown condition in six hours and in a cold shutdown condition in the l t

following 18 hours2.083333e-4 days <br />0.005 hours <br />2.97619e-5 weeks <br />6.849e-6 months <br />.

Cote 6 - Within 30 days following the loss of one indication, or 7 days following the loss of both indications,-

i restore the inoperable channel (s) to an operable status or a special report to the Commission pursuant to

! Specification 6.7 aust be prepared and submitted within the subsequent 14 days, outlining the action taken, ,

the cause of the inoperability, and the plans and schedule for restoring the system to operable status.

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Amendment No. 63 49b ~l I

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'VYNPS .

TABLE 3.2.7 T0XIC CAS MONITORING SYSTEM Minimum Number of Required Action When Miniaana Operable Instrument Trip Conditions of Operations Are Not Channels Function Settina Satisfied 2 Initiate emergency Chlorine i S ppm Note 1 Control Room breathing Ammonia s 75 ppa sic Vinyl Chloride 1 800 ppm Carbon Dioxide s 800 ppa Methanol 1 300 ppa Note 1 - Within 30 days following the loss of one indication, or 7 days following the loss of both indications, restore the inoperable channel (s) to an operable status or a special report to the Connaission pursuant to l

Specification 6.7 naast be prepared and submitted within the subsequent 14 days, outlining the action taken, the cause of the inoperability, and the plans and schedula for restoring the system to operable status.

49C Amendment No. 63 ,

VYMPS TABLE 4.2.6 CALIBitATION REQUIRENINTS POST-ACCIDENT INSTRUNENTATION i

l l Parameter Calibration Instnament Check Drywell Atmosphere Temperature Every 6 months Once each day-.

C:ntainment Pressure Once/ Operating Cycle Once each day Tarua Pressure Every 6 months Once each day T:rus Water Level once/ Operating cycle once each day Tsrus Water Temperature Every 6 months Once each day Racetor Pressure Once/ Operating Cycle .Once each day R cctor Vessel Water Level Once/ Operating Cycle Once each day C:ntrol Rod Position (Note 5) Once each day Neutron Monitor Same as Reactor Protection Once each day Systems Terus Air Temperature Every 6 months Once each day Safsty/ Relief Valve Position Every refueling outage (Note 9) Once each day (a Functional Test to be performed quarterly)

SOfsty Valve Position Every refueling outage (Note 9) Once each day (a Functional Test to be performed quarterly) .

Amendment No. 63 60

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9 VYNPS TABLE 4.2.6 CAT.TBRATION REQUIREIENTS POST-ACCIDENT INSTRUNENTATION (Cont)

Earameter Calibration Instrument Check Containment Hydrogen /0xygen Monitor Once/ Operating Cycle Once each day Centainment High-Range. Radiation Monitor Once/ Operating Cycle Once each day-i Amendment No. 60s

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VYNPS TABLE 4.2.7 T0XIC GAS MONITORING SYSTEM - CALIBRATION REOUIREMENTS Parameter Calibration Instrument Check T xic Cas Monitoring System Once/ Operating Cycle Once each day Amendment No.

61b

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VYNPS 3.2 (Continued) standby gas treatment system operation so that none of the activity released'during:the refueling accident-leave the Reactor Building via the normal ventilation stack but 'that all activity is processsed by the standby' gas.

treatment system. Trip settings for the monitors in the ventilation duct are based upoa initiation of the-normal ventilation isolation and standby gas treatment system operation at a radiation level equivalent to the maximum release rate of.0.08/E Ci/see given in. Specification 3.8.C.1.a. The monitoring ~ system in the plant stack represents a backup to this system to limit gross radioactivity releases to the environs,.

.The purpose of isolating the mechanical. vacuum pump'line is to limit release of radioactivity from the main condenser. During an accident, fission products would be transported from~the reactor through the main steam-line to the main condenser. The fission product radioactivity would be sensed by the main steam line radiation monitors which initiate isolation.

Post-accident instrumentation parameters for Containment Pressure. Torus Water Level, Containment' Hydrogen / Oxygen Monitor, and Containment High-Range Radiation Monitor, are redundant, environmentally and seismically qualified instruments provided to enhance the operators' ability to follow the course of an event.

The purpose of each of these instruments is to provide detection and measurement capability during and following an accident as required by NUREG-0737 by ensuring continuous on-scale indication of the following: containment pressure in the 0 to 275 psia range; torus water level in the O to 20 foot range (i.e., the bottom to 5 feet above the normal water level of the torus pool); containment hydrogen / oxygen concentrations-(0 to 30% hydrogen '

and 0 to 25% oxygen); and containment radiation in the 1 R/hr to 107 R/hr gasma. The Control Room Toxic Cas Monitor assures that the Control Room operators, Wherever required to be in the Control Room, will be adequately protected against the effects of an accidental release of toxic gases and that the plant can be safely. operated-or shut down under design basis accident conditions.

4.2 PROTECTIVE INSTRUMENTATION The protective instrumentation systems covered by this Specification are listed in Table 4.2. Most of these protective systems are composed of two or more independent and redundant subsystems which are combined in a dual-channel arrangement. Each of these subsystems contains an arrangement of electrical relays which operate to initiate the required system protective action.

The relays in a subsystem are actuated by a number of means, including manually-operated switches, ,

process-operated switches (sensors), bistable devices operated by analog sensor signals, timers, limit switches, and other relays. In most cases, final subsystem relay actuation is obtained by satisfying the. logic conditions ,

t established by a number of these relay contacts in a logic. array. When a subsystem is actuated, the final subsystem relay (s) can operate protective equipment, such as valves and puses, and can perform other protective

, actions, such as tripping the main turbine generator unit. +

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Amendment No 66 i ,

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VYMPS. .

I 4.2 (Continued) '

1 l With the dual-channel arrangement o'f these subsystems, tho' single failure of'a ready circuit-can be' tolerated i because the redundant subsystem or system (,in the case of high pressure coolant' injection) will then initiate j .the necessary protective action. If a failure in one of these circuits occurs in such a way that an action is l taken, the operator is inunediately alerted to the failure. If the failure occurs and causes no action, it could i then remain undetected, causing'a loss of the redundancy in the dual-channel arrangement. Losses in redundancy '

i of this nature are found by periodically testing the relay circuits in the subsystems to assure that they are j operating properly.

It has been the practice in boiling water reactor plants to functionally test protective instrumentat' ion sensors d

and sensor. relays on-line on a monthly frequency. Since logic circuit tests result in the actuation of plant

. equipment, testing of this nature was done while the plant was shutdown for refueling. In this way, the testing of. equipment would not jeopardize plant operation. However, a refueling interval'could be as long as-eighteen l , months, which is too long a period to allow an undetected failure to exist.

j This specification is a periodic testing program which is based upon the overall on-line testing'of protective i

instrumentation systems,. including logic circuits,as well as sensor circuits. Table 4.2 outlined the test,.

calibration, and logic system functional test schedule for the protective instrumentation systems. The testing of a subsystem includes a functional test of each relay wherever practicable. .The testing of each relay l includes all circuitry necessary to make the relay operate, and also the proper functioning of the relay i contacts. Functicnal testing of the inaccessible temperature switches associated.with the isolation systems is i accomplished remotely by application of a heat source to individual switches.

i l All subsystems are functionally tested, calibrated, and operated in their entirety if practicable. Certain l

exceptions are necessary because the actuation of certain relays would jeopardize plant operation oc present an operational hardship.

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For example, certain relays trip recirculation system discharge valves, and the actuation of these' relays would

! cause a severe plant transient. In cases of this nature, the devices in the relay circuit will be tested, but- .

the relay will only be actuated during a refueling outage. The number of relays in this category is very small l

l compared to the total number of identical relays being tested on-line.

1 i Amendment No 67

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