ML20059F978

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Proposed Tech Specs Re Main Control Room Intake Radiation Monitors & Seismic Monitoring Instrumentation
ML20059F978
Person / Time
Site: Peach Bottom  Constellation icon.png
Issue date: 11/01/1993
From:
PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:
Shared Package
ML20059F977 List:
References
NUDOCS 9311050203
Download: ML20059F978 (23)
v • d • e


Text

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i ATTACHMENT 2 r

PEACH BOTTOM ATOMIC POWER STATION UNITS 2 AND 3 l

4 Docket Nos. 50-277 -i 50-278 License Nos. DPR-44 l DPR-56  :

i TECHNICAL SPECIFICATION CHANGE REQUEST -

91-06 t

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" Main Control Room Intake Air Radiation Monitors"

" Seismic Monitoring Instrumentation" i 8

List of Attached Pages l Unit 2 Unit 3 59 59 75 75 l 84 84 5

93 93 97 97 i 233a 233a 234 234 235 235

  • 240v 240v f

9311050203 931101 O l' PDR P

ADDCK 05000277 /

PDR B l

L Unit 2 PBAPS LIMITING CONDITION FOR OPERATION SURVEILLANCE REOUIREMENTS 3.2.D. Radiation Monitorino 4.2.D. Radiation Monitorina Systems-Isolation and Systems-Isolation and Initiation Functions Initiation Functions

1. Reactor Buildina Isolation 1. Reactor Building Isolation and Standby Gas Treatment and StandLv Gas Treatment System System The limiting conditions Instrumentation shall be for operation are given in functionally tested, cali-Table 3.2.D. brated and checked as indi-cated in Table 4.2.D.
2. Main Control Room l

System logic shall be The limiting conditions for functionally tested as

' operation are given in indicated in Table 4.2.D.

Table 3.2.D.

2. Main Control Room E. Drywell Leak Detection i

Instrumentation shall be The limiting conditions of functionally tested, operation for the instru- calibrated and checked as mentation that monitors indicated in Table 4.2.D.

drywell leak detection are given in Section 3.6.C, E. Drvwell Leak Detection

" Coolant Leakage".

Instrumentation shall be calibrated and checked as indicated in table 4.2.E.

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Unit 3 i PBAPS  !

LIMITING CONDITION FOR OPERATION SURVEILLANCE REOUIREMENTS 3.2.D. Radiation Monitorino 4.2.D. Radiation Monitoring i Systems-Isolation and Systems-Isolation and I Initiation Functions Initiation Functions

1. Reactor Buildina Isolation 1. Reactor Buildina Isolation and Standbv Gas Treatment and Standby Gas Treatment  ;

System System  :

The limiting conditions Instrumentation shall be l for operation are given in functionally tested, cali-Table 3.2.D. brated and checked as indi-cated in Table 4.2.D.

2. Main Control Room System logic shall be The limiting conditions for functionally tested as operation are given in indicated in Table 4.2.D.  :

Table 3.2.D.

2. Main Control Room E. Drvwell Leak Detection f Instrumentation shall be  ;

The limiting conditions of functionally tested,  !

operation for the instru- calibrated and checked as  !

mentation that monitors indicated'in Table 4.2.D. i drywell leak detection are i given in Section 3.6.C, E. Drywell Leak Detection

" Coolant Leakage".

Instrumentation shall be '

calibrated and checked as indicated in table 4.2.E. j i

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Unit 2 PBAPS -

TABLE 3.2.D RADIATION MONITORING SYSTEMS THAT INITIATE AND/OR ISCLATE SYSTEMS j Minimum No.

of Operable Instrument No. of Instrument .l Channels per Channels Provided Action Trip System Trip Function Trip Level Setting by Design (2)

(1) 2 Refuel Area Exhaust Upscale, <16 mr/hr 4 Inst. Channels A or B Monitor 2 Reactor Building Upscale, <16 mr/hr 4 Inst. Channels B Exhaust Monitors 1 (3) Main Stack Monitor Upscale, $106 cps 2 Inst. Channels C l

2 (4) Main Control Room Upscale, <400 cpm 4 Inst. Channels D l Notes for Table 3.2.D

1. Whenever the systems are required to be operable, the specified number of instrument channels shall be operable or placed in the tripped condition. If this cannot be met, the indicated action shall be taken.
2. Action A. Cease operation of the refueling equipment.

B. Isolate secondary containment and start the standby gas treatment system.

C. Cease purging of primary containment, and close vent and purge valves greater than 2 inches in diameter.

l D. As described in LCO 3.11.A.5

3. The trip function is required to be operable only when the containment is purging through the SGTS and containment integrity is required. If both radiation monitors are out of service, action shall be taken as indicated in Note 2, (C).

4..The trip function is required to be operable whenever secondary containment is required on either unit.

Unit 3 PBAPS

  • TABLE 3.2.D RADIATION MONITORING SYSTEMS THAT INITIATE AND/OR ISOLATE SYSTEMS Minimum No.

of Operable Instrument No. of Instrument Channels per Channels Provided Action Trip System Trip Function Trip Level Setting by Design (2)

(1) 2 Refuel Area Exhaust Upscale, <16 mr/hr 4 Inst. Channels A or B Monitor 2 Reactor Building Upscale, <16 mr/hr 4 Inst. Channels B Exhaust Monitors 1 (3) Main Stack Monitor Upscale, $106 cps 2 Inst. Channels C i

yIl 2 (4) Main Control Room Upscale, <400 cpm 4 Inst. Channels D Notes for Table 3.2.D

1. Whenever the systems are required to be operable, the specified number of instrument channels shall be operable or placed in the tripped condition. If this cannot be met, the indicated action shall be taken.
2. Action A. Cease operation of the refueling equipment.

B. Isolate secondary containment and start the standby gas treatment system.

C. Cease purging of primary containment, and close vent and purge valves greater than 2 inches in diameter.

l D. As described in LCO 3.11.A.5

3. The trip function is required to be operable only when the containment is purging through the SGTS and containment integrity is required. If both radiation monitors are out of service, action shall be taken as indicated in Note 2, (C).
4. The trip function is required to be operable whenever secondary containment is required on either unit.

Unit 2 PBAPS TABLE 4.2.D MINIMUM TEST & CALIBRATION FREQUENCY FOR RADIATION MONITORING SYSTEMS Instrument Functional Instrument Instrument Channels Test Calibration Check (2)

1) Refuel Area Exhaust (1) Once/3 months Once/ day Monitors - Upscale
2) Reactor Building Area (1) Once/3 months Once/ day
3) Main Stack Monitor Once/3 months Once/12 months Once/ day.

i as described in

$ 4.8.C.4.a

4) Main Control Room Once/3 months Once/18 months Once/ day as described in 4.11.A.5 Loaic System Functional Test (4) (6) Frecuency
1) Reactor Building Isolation Once/6 months
2) Standby Gas Treatment Once/6 months system Actuation  ;

. - _ - . . _ . . - - . . - - . . - - - . _ _ _ _ _ - . . - _ . _ . . _ - - . _ _ _ _ - _ . _ _ _ _ _ . . - - _ - _ - _ _ _ - . _ _ _ - - _ _ - _ _ _ _ . - - _ -_ _ _ . _ _ - _ _ _ - _ _ _ _ - - . , - _ _ _ . _ - _ . - - - - - - _ - - . - - _ . , ~ ~ . - - . . . .

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L Unit 3:

PBAPS TABLE 4.2.D MINIMUM TEST & CALIBRATION FREOUENCY FOR RADIATION MONITORING SYSTEMS Instrument Functional Instrument Instrument Channels Test Calibration Check (2)

1) Refuel Area Exhaust (1) Once/3 months Once/ day i Monitors - Upscale
2) Reactor Building Area (1) Once/3 months once/ day.

, 3) Main Stack Monitor Once/3 months once/12 months Once/ day '

m as described in f 4.8.C.4.a

4) Main Control Room Once/3 months Once/18 months Once/ day as described in 4.11.A.5 Locic System Functional Test (4) (6) Frecuency
1) Reactor Building Isolation Once/6 months
2) Standby Gas Treatment Once/6 months System Actuation t

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Unit 2 (

PBAPS )

3.2 BASES (Cont'd) [

f Four sets of two radiation monitors are provided which [

initiate the Reactor Building Isolation function and operation of i the standby gas treatment system. Four instrument channels monitor l the radiation from the refueling area ventilation exhaust ducts and i four instrument channels monitor the building ventilation below the l refueling floor. Each set of instrument channels is arranged in a  !

1 out of 2 twice trip logic.  ;

Trip settings of less than 16 mr/hr for the monitors in the refueling area ventilation exhaust ducts are based upon ini-tiating normal ventilation isolation and standby gas treatment system operation so that none of the activity released during the j refueling accident leaves the Reactor Building via the normal  :

ventilation path but rather all the activity is processed by the j standby gas treatment system. l Two channels of nonsafety-related radiation monitors are k provided in the main stack. Trip signals from these monitors are  !

required only when purging the containment through the SGTS and i containment integrity is required. The trip signale isolate pri- {

mary containment vent and purge valves greater than 2 inches in i diameter to prevent accidental releases of radioactivity offsite when the valves are open. This signal is added to fulfill the ,

requirements of item II.E.4.2(7) of NUREG-0737. i Four channels of in-duct radiation monitors are provided )

which initiate the Main Control Room Emergency Ventilation System. j Each set of instrument channels are arranged in a one (1) out of two. i (2) twice trip logic. {

I Flow integrators are used to record the integrated flow j of liquid from the drywell sumps. The integrated flow is indica-  ;

tive of reactor coolant leakage. A Drywell Atmosphere Radioactivity 1 Monitor is provided to give supporting information to that supplied i by the reactor coolant leakage monitoring system. (See Bases for  :

3.6.C and 4.6.C) l l

Some of the surveillance instrumentation listed in Table ,

3.2.F are required to meet the accident monitoring requirementF /

l NUREG-0737, Clarification of TMI Action Plan Requirements. Th2  ;

instrumentation and the applicable NUREG-0737 requirements are: I

1. Wide range drywell pressure (II.F.1.4) 1
2. Subatmospheric drywell pressure (II.F.1.4) l
3. Wide range suppression chamber water level (II.F.1.5)
4. Main stack high range radiation monitor (II.F.1.1)
5. Reactor building roof vent high range radiation monitor (II.F.1.1)
6. Drywell hydrogen concentration analyzer and monitor (II.F.1.6)
7. Drywell high range radiation monitors (II.F.1.3)
8. Reactor Water Level - wide and fuel range (II.F.2)
9. Safety-Relief Valve position indication (II.D.3) l 4

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'I Unit 3 PBAPS

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3.2 BASES (Cont'd) .i i

Four sets of two radiation monitors are provided which i initiate the Reactor Building Isolation function and'op% ration of l the standby gas treatment system. Four instrument channels monitor j the radiation from the refueling area ventilation exhaust ducts and i four instrument channels nonitor the building ventilation below the refueling floor. Each set of instrument channels is arranged in a

(

1 out of 2 twice trip logic.  ;

Trip settings of less than 16 mr/hr for the monitors in j the refueling area ventilation exhaust ducts are based upon ini-  !

tiating normal ventilation isolation and standby gas treatment i system operation so that none of the activity released during the t refueling accident leaves the Reactor Building via the normal -

ventilation path but rather all the activity is processed by the '

standby gas treatment system.

Two channels of nonsafety-related radiation monitors are l' provided in the main stack. Trip signals from these monitors are required only when purging the containment through the SGTS and  !

containment integrity is required. The trip signals isolate pri-  ;

mary containment vent and purge valves greater than 2 inches in  ;

diameter to prevent accidental releases of radioactivity offsite ,

when the valves are open. This signal is added to fulfill the  !

requirements of item II.E.4.2(7) of NUREG-0737. t Four channels of in-duct radiation monitors are provided [

which initiate the Main Control Room Emergency Ventilation System. i Each set of instrument channels are arranged in a one (1) out of two (2) twice trip logic.

Flow integrators are used to record the integrated flow  !

of liquid from the drywell sumps. The integrated flow is indica- 3 tive of reactor coolant leakage. A Drywell Atmosphere Radioactivity ,

Monitor is provided to give supporting information to that supplied  ;

by the reactor coolant leakage monitoring system. (See Bases for i 3.6.C and 4.6.C)  !

Some of the surveillance instrumentation listed in Table i 3.2.F are required to meet the accident monitoring requirements of .

NUREG-0737, Clarification of TMI Action Plan Requirements. This instrumentation and the applicable NUREG-0737 requirements are: [

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1. Wide range drywell pressure (II.F.1.4) l
2. Subatmospheric drywell pressure (II.F.1.4) t
3. Wide range suppression chamber water level (II.F.1.5) ,
4. Main stack high range radiation monitor (II.F.1.1)
5. Reactor building roof vent high range radiation monitor ,

(II.F.1.1)  !

6. Drywell hydrogen concentration analyzer and monitor {

(II.F.1.6)  !

7. Drywell high range radiation monitors (II.F.1.3) ,
8. Reactor Water Level - wide and fuel range (II.F.2)  !
9. Safety-Relief Valve position indication (II.D.3) k

f; Unit 2 l PBAPS l 4.2 BASES (cont'd) i The radiation monitors in the refueling area ventilation .

duct which initiate building isoldtion and standby gas treatment  !

-operation are arranged in a 1 out of 2 twice logic system. Sme i bases given above for the rod blocks apply here also and were used  !

to arrive at the functional testing frequency. The air ejector '

off-gas monitors are connected in a 2 out of 2 logic arrangement. i Based on the experience with instruments of similar design, a j testing interval of once every three months has been found  :

adequate.  !

Radiation monitors in the main stack which initiate 'l containment isolation are not safety-related and are required only .

during containment purging through the SGTS and when containment l integrity is required, an activity which occurs infrequently. l Therefore, a twelve (12) month calibration interval is appropriate. .i The Control Room Intake Air Radiation Monitors are l safety-related and are required to be operable at all times when  !

secondary containment is required. The calibration interval is as  !

i described in Section 4.11.A. l i .

The automatic pressure relief instrumentation can be j

- considered to be a 1 out of 2 logic system and the discussion  ;

J above applies also. }

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PBAPS i

4.2 BASES (cont'd)  ;

The radiation monitors in the refueling-area ventilation .

duct which initiate building isolation and standby gas treatment i operation are arranged in a 1 out of 2 twice logic system. The l bases given above for the rod blocks apply here also and were used j to arrive at the functional testing frequency' . The air ejector off-gas monitors are connected in a 2 out of 2 logic arrangement. i Based on the experience with instruments of similar design, a i testing interval of once every three months has been found -j adequate. i i

Radiation monitors in the main stack which initiate l containment isolation are not safety-related and are required only  !

during containment purging through the SGTS and when containment i integrity is required, an activity which occurs infrequently.  !

Therefore, a twelve (12) month calibration interval is appropriat,e. I t

The Control Room Intake Air Radiation Monitors are safety-related and are required to be operable at all times when secondary containment is required. The calibration interval is as ,

described in Section 4.11.A. j The automatic pressure relief instrumentation can be considered to be a 1 out of 2 logic system and the discussion above applies also. )

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Unit 2 )

PBAPS  ;

LIMITING CONDITION FOR OPERATION SURVEILLANCE REOUIREMENTS I

b. The results of laboratory d. A dry gas purge shall carbon sample analysis be provided to the filters '

shall show 90% radioactive to insure that the methyl iodide removal at relative humidity in the a velocity within 20% filter systems does not  !

of system design, 0.05 exceed 70% during idle to 0.15 mg/m3 inlet periods. l methyl iodide concentra-tion, 2 95% relative e. A sample of the charcoal humidity and 2 125 degrees F, filter shall be analyzed once ,

^

or that filter train shall per year to assure halogen not be considered operable. removal efficiency of at least ,

99.5 percent.

c. Fans shall be shown to Once every 18 months automatic operate at approximately 3.

3,000 CFM 300 CFM initiation of control room (design flow for the emergency ventilation, from ,

filter train), all designed initiation signals shall be demonstrated.

5. The main control room ventilation radiation 4. Operability of the main monitors, which monitor main control room ventilation control room ventilation radiation monitors and flow ,

radiation levels, snall switches shall be functionally be operable at all times tested every 3 months.

when secondary containment is required. 5. The main control room '

radiation monitors shall be

a. One radiation monitoring calibrated electronically and channel may be inoperable for with a known radioactivc 7 days, as long as the source positioned in a remaining radiation monitoring reproducible geometry with channel maintains the respect to the sensor every 18 capability of initiating months.

emergency ventilation on any .

designed trip functions. 6. The main control room ventilation supply flow

b. A trip system is operable when switches shall be calibrated 1 of 2 channels is available to every 18 months.

provide its trip function and -

the inoperable channel is  ;

placed in its tripped  !

condition. If a channel is I inoperable or placed in its .

tripped condition in both l trip systems, then emergency  ;

ventilation must be initiated i and maintained.

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r Unit 3 PBAPS LIMITING CONDITION FOR OPERATION SURVEILLANCE REOUIREMENTS

b. The results of laboratory d. A dry gas purge shall carbon sample analysis' be provided to the filters '

shall show 90% radioactive to insure that the methyl iodide removal at relative humidity in the a velocity within 20% filter systems does not of system design, 0.05 exceed 70% during idle

  • to 0.15 mg/m3 inlet periods.

methyl iodide concentra-tion, 2 95% relative e. A sample of the charcoal humidity and 2 125 degrees F, filter shall be analyzed once or that filter train shall per year to assure halogen not be considered operable. removal efficiency of at least 99.5 percent.

c. Fans shall be shown to '

operate at approximately 3. Once every 18 months automatic 3,000 CFM 300 CFM initiation of control room '

(design flow for the emergency ventilation, from filter train). all designed initiation signals shall be demonstrated.

5. The main control room ventilation radiation 4. Operability of the main monitors, which monitor main control room ventilation control room ventilation radiation monitors and flow radiation levels shall switches shall be functionally be operable at all times tested every 3 months.

When secondary containment is i required. 5. The main control room radiation monitors shall be  :

a. One radiation monitoring calibrated electronically and -

channel may be inoperable for with a known radioactive 7 days, as long as the source positioned in a remaining radiation monitoring reproducible geometry with channel maintains the respect to the sensor every 18 capability of initiating months. ,

emergency ventilation on any i designed trip functions. 6. The main control room ventilation supply flow

b. A trip system is operable when switches shall be calibrated 1 of 2 channels is available to every 18 months.

provide its trip function and the inoperable channel is ',

placed in its tripped condition. If a channel is inoperable or placed in its tripped condition in both trip systems, then emergency ventilation must be initiated and maintained. j

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Unit 2 PBAPS LIMITING CONDITIONS FOR OPERATION SURVEILLANCE REOUIREMENTS 3.ll.A (cont'd.) 4.11.A (cont'd).

6. The main control room ventilation supply flow switches shall be operable at all times when secondary containment is required except B. Emercency Heat Sink Facility one flow switch may be inoperable for 7 days as long 1. The level in the emergency as the other flow switch is reservoir of the Emergency operable. Heat Sink Facility shall be checked once per month. ,
7. If specification 3.11.A.5 or 3.ll.A.6 cannot be met, 2. Once a year the portable  !

manually initiate and maintain fire pump which is used to main control room emergency provide makeup water to the ventilation, emergency reservoir will be l

checked for operability and l B, Emercencv Heat Sink Facility availability.  !

The level in the emergency 3a. The Emergency Cooling Water l reservoir of the Emergency Heat pump and ESW booster l Sink Facility shall not be less pumps shall be tested in  ;

than 17'. Should the level accordance with Section XI drop below this point action of the ASME Boiler Pressure shall be taken to restore Vessel Code and applicable the level to above the minimum, addenda, except where relief within 7 days. has been granted.

I C. Emeroencv Shutdown Control Panel b. The Emergency Cooling Tower fans shall be tested every three

1. At all times when not in use months to verify operability.

or being maintained, the emergency shutdown control C. Emeroency Shutdown Control Panel panels shall be secured.

1. The emergency shutdown control panels shall be visually checked once per week to verify they are secured.
2. Operability of the switches on the emergency shutdown control panels shall be tested by electrical check once per refueling outage.

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t Unit 3  ;

PBAP3

_ LIMITING CONDITIONS FOR OPERATION SURVEILLANCE REOUIREMENTS l 3.11.A (cont'd.) 4.11.A (cont'd).  !

6. The main control room f ventilation supply flow t switches shall be operable at  !

all times when secondary  !

containment is required except B. Emeroency Heat Sink Facility  :

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one flow switch may be inoperable for 7 days as long 1. The level in'the emergency as the other flow switch is reservoir of the Emergency operable. Heat Sink' Facility shall be  !

checked once per month. i

7. If specification 3.11.A.5 or 3.11.A.6 cannot be met., 2. Once a year the portable manually initiate and reaintain fire pump which is.used to main control room emergency provide makeup water to the ventilation. emergency reservoir will be i checked for operability and j B. Emercency Heat Sink Facility availability. l The level in the emeroency 3a. The Emergency Cooling Water reservoir of the Emergency Heat pump and ESW booster l

Sink Facility shall not be less pumps shall be tested in ,

than 17'. Should the level accordance with Section XI .

drop below this point action of the ASME Boiler Pressure-  ;

shall be taken to restore Vessel Code and applicable I the level to above the ndnimum, addenda, except where relief i within 7 days. has been granted. l j -!

C. Emercency Shutdown Control Panel b. The Emergency Cooling Tower ,

fans shall be tested every three l

1. At all times when not in use months to verify operability. '

or being maintained, the emergency shutdown control C. Emeroency Shutdown Control Panel l panels shall be secured.  !

1. The emergency shutdown control ,

panels shall be visually checked '

once per week.to verify they  ;

are secured.

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2. Operability of the switches on the emergency shutdown control panels shall be  ;

tested by electrical check i once per refueling outage. )

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l Unit 2  :

PBAPS  :

3.11 BASES A. Main Control Room Emerrency Ventilation System l

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The control room emergency ventilation system (CREV) is designed to filter the control room intake air during control room isolation conditions. The CREV system is designed to automatically start upon receipt of control room isolation signals I and to maintain the control room at a positive pressure so that all leakage  !

should be out-leakage.  !

High efficiency particulate absolute (HEPA) filters are installed before the f charcoal adsorbers to prevent clogging of the iodine adsorbers. The charcoal l adsorbers are installed to reduce the potential intake of radiciodine to the control room. The in-place test results should indicate a system leak tightness of less than 1 percent bypass leakage for the charcoal adsorbers and a HEPA efficiency of at least 99 percent removal of DOP particulates. The laboratory carbon sample test results should indicate a radioactive methyl iodide removal ,

efficiency of at least 90 percent for expected accident conditions If the  !

efficiencies of the HEPA filters and charcoal adsorbers are as specified, the resulting doses will be less than the allowable 1e'vels states in Criterion 19 of the General Design Criteria for Nuclear Power Plants, Appendix A to 10 CFR  ;

Part 50. j One main control room emergency ventilation air supply i n provides adequate ventilation flow under accident conditions. Should one .mergency ventilation j air supply fan and/or fresh air filter train be out of service during reactor {

operation, the allowable repair time for 7 days is justif ed.

l At least 1 of 2 channels per trip system in the Control Room Ventilation Radiation  ;

Monitoring System for indication and alarm of radioactive air being drawn into  !

the main control room is considered adequate, provided that 3 of the 4 channels l are available. With one channel of control room radiation monitoring inoperable  !

I the capability of automatically initiating emergency ventilation on receipt of any trip signal is still maintained and at no time is the ability to manually l initiate emergency ventilation lost. Therefore, the allowable time for repair of 7 days is justified. When one (1) radiation monitoring channel in both trip j j systems are inoperable, then emergency ventilation shall be initiated and maintained. Main control room emergency ventilation is initiated when a trip ,

j signal from the radiation detectors is given via high radiation or downscale/ failure signal (one out of two twice logic) or loss of divisional power to local radiation monitoring system panel. Main control room emergency

!- ventilation is also initiated on a low flow signal from one of two flow switches l in the main control room normal supply after a time delay. l 1  ;

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PBAPS  !

$ 3.11 BASES e A. Main Control Poom Emerrency Ventilation System I

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The control room emergency ventilation system (CREV) is designed to filter the  !

l control room intake air during control room isolation conditions. The CREV system f j is designed to automatically start upon receipt of control room isolation signals )

and to maintain the control room at a positive pressure so that all leakage j 2

should be out-leakage.  !

i High efficiency particulate absolute (HEPA) filters are installed before the

-l charcoal adsorbers to prevent clogging of the iodine adsorbers. The charcoal j l ndsorbers are installeo to reduce the potential intake of radiciodine to the j control room. The in-place test results should indicate a system leak tightness l of less than 1 percent bypass leakage for the charcoal adsorbers and a HEPA efficiency of at least 99 percent removal of DOP particulates. The laboratory l

carbon sample test results should indicate a radioactive methyl iodide removal l l efficiency of at least 90 percent for expected accident conditions. If the {

i efficiencies of the HEPA filters and charcoal adsorbers are as specified, the i resulting doses sill be less than the allowable levels states in Criterion 19 of the General Design Criteria for Nuclear Power plants, Appendix A to 10 CFR Part 50.  !

one main control room emergency ventilation air supply fan provides adequate ventilation flow under accident conditions. Should one emergency ventilation j air supply fan and/or fresh air filter train be out of service during reactor operation, the allowable repair time for 7 days is justified. l4 At least 1 of 2 channels per trip system in the Control Room Ventilation Radiation

! Monitoring System for indication and alarm of radioactive air being drawn into '

the main control room is considered adequate, provided that 3 of the 4 channels are available. Vith one channel of control room radiation monitoring inoperable

, the capability of automatically initiating emergency ventilation on receipt of 1 any trip signal is still maintained and at no time is the ability to manually l initiate emergency ventilation lost. Therefore, the allowable time for repair of 7 days is justified. When one (1) radiation monitoring channel in both trip l

systems are inoperable, then emergency ventilation shall be initiated and maintained. Main control room emergency ventilation is initiated when a trip 4 signal from the radiation detectors is given via high radiation or

]' downscale/ failure signal (one out of two twice logic) or loss of divisional power j to local radiation monitoring system panel. Main control room emergency ventilation is also initiated on a low flow signal from one of two flow switches )

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, in the main control room normal supply after a time delay.

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PBAPS t

TABLE 4.15** i l

SEISMIC MONITORING INSTRUMENTATION SURVEILLANCE REOUIREMENTS l l

1 Instrument

  • l Instrument
  • Functional Instrument 1 Instruments and Sensor Locations # Check Test Calibration  !
1. Triaxial Time-History Accelerographs
a. Containment Foundation l 2

(torus compartment) M SA R

b. Refueling Floor M SA R j
c. RCIC Pump (Rm #7) M SA R j
d. "C" Diesel Generator M SA R (

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2. Triaxial Peak Accelerographs  !
a. Reactor Piping (Drywell) NA NA R I
b. Refueling Floor NA NA R i
c. "C" Diesel Generator NA NA R '
3. Central Recording and Analysis l System '
a. Cable Spreading Rm M SA R r

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  • Surveillance Frecmencies f i

l M: every month t SA: every 6 months l R: every 24 months i

] ** Effective upon completion of installation.

  1. Seismic instrumentation located in Unit 2. j 1

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PBAPS  :

i TABLE 4.15** }

l jiEISMIC MONITORING INSTRUMENTATION SURVEILLANCE REOUIREMENTS  !

l Instrument

  • i Instrument
  • Functional Instrument Instruments and Sensor Locations # Check Test Calibration l I
1. Triaxial Time-History Accelerographs  !

i a.-Containrent Foundation  !

, (torus compartment) M SA R j M SA R -

b. Refueling Floor
c. RCIC Pump (Rm #7) M SA R l
d. "C" Diesel Generator M SA R t
2. Triaxial Peak Accelerographs  :

I

a. Reactor Piping (Drywell) NA NA R
b. Refueling Floor NA NA R  ;
c. "C" Diesel Generator NA NA R l
3. Central Recording and Analysis l' System
a. Cable Spreading Rm M SA R '
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  1. Seismic instrumentation located in Unit 2. l 4 I l

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ATTACHMENT 3 l l

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I PEACH BOTTOM ATOMIC POWER STATION UNITS 2 AND 3 t

l Docket Nos. 50-277 50-278 ,

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l License Nos. DPR-44 ~i i

l DPR ,

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.;s TECHNICAL SPECIFICATION CHANGE REQUEST l 91-06 j e

" Main Control Room Intake Air Radiation Monitors" '

" Seismic Monitoring Instrumentation" I

Description of Watchdog Circuitry ,

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'TSCR 91-06 Docket Nos. 50-277

~50-278 License Nos. DPR-44 DPR-56 NRC microprocessor based instruments contain a " watchdog" circuit to detect failures that may cause the microprocessor to cease functioning. This circuit is implemented in hardware and ,

is not software driven. In general, the watchdog circuit times )

out after a period of microprocessor inactivity and annunciates a failure after the time out period has elapsed.

l The hardware implementation of the software reset circuitry (deadman switch) is described below. Refer to Figure 1 as required.

1 Initial system power on and / RESET pulse 1 l

When the unit is first powered on the system, a five volt power supply (+5V) is applied to the RC circuit comprised of R13 and C29. The delayed voltage on C29 is applied to the reset pin of U12A and U12B as well as U21C pin 10. This delayed voltage holds U12A and U12B in a reset state for approximately 1.5 seconds. The reset state causes U12 pin 9 to be at logic 0.

With U21C pins 9 and 10 both at logic 0 the microprocessor master reset line (/ RESET) is also held at logic O. A logic 0 on / RESET holds the processor in a halted state where no software is executed.

The microprocessor will remain halted until the / RESET line is set to a logic 1. This occurs when C29 charges to approximately 2.5 volts. At that time U12A and U12B are released from their reset state and U12B pin 9 will be set to logic 1.

Both U21C pins 9 and 10 are now logic 1, and the / RESET line will be set high, allowing the processor to begin executing software instructions.

REFRESH sicnal and automatic system reset During system operation the microprocessor executes a software instruction which produces a / REFRESH signal approximately every 250 microseconds. The / REFRESH signal is applied to the U12A causing it to remain in a triggered state, with its output Q (U12A pin 6) at logic 1. The net effect of this is U12B pin 11 is logic 1, therefore U12B pin.9 is high and

/ RESET remains logic 1 and the microprocessor operate normally.

If the microprocessor should fail to execute software correctly or freeze for any reason, U12 would provide a microprocessor hardware reset as follows. With U12A pin 5 not being refreshed, U12A would time out after approximately 1.2 seconds, the time constant of R15 and C28. This would cause U12A pin 6 to be set to a logic 0, triggering U12B. U12B would then

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'TSCR 91-06 Docket Nos. 50-277 f 50-278  ;

License Nos. DPR-44 -

DPR-56 j produce a logic 0 pulse of 63 milliseconds at pin 9. This pulse  !

would appear on / RESET causing the microprocessor to perform a i hardware reset and begin operating as normal. Once the  ;

microprocessor is reset and executes normal software  ;

instructions, it would then begin producing the / REFRESH signal and the system would continue to operate normally.

Failure relay activation from hardware In addition to the deadman switch, an extra level of failure detection is built into the system by the use of a normally energized failure relay contact. The failure relay is controlled i by a data latch external to the microprocessor. The ,

microprocessor can manipulate the data latch, but the master  ;

reset line on the data latch is controlled by the / RESET line of the deadman circuitry. Therefore any / RESET pulse will reset the ..

data latch, de-energize the failure relay, and cause a failure i alarm state. In the case of multiple system resets due to the microprocessor being repeatedly reset but then freezing, each  !

/ RESET pulse would guarantee the fail relay was de-energized and in the fail alarm state.

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