ML20086G132

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Proposed Tech Specs Re Increase in Allowable Post Accident in-leakage Rate for CR
ML20086G132
Person / Time
Site: Millstone Dominion icon.png
Issue date: 07/07/1995
From:
NORTHEAST NUCLEAR ENERGY CO.
To:
Shared Package
ML20086G129 List:
References
NUDOCS 9507140145
Download: ML20086G132 (12)
v • d • e


Text

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May 23,1994 PUUf7 SYSTEMS SURVEILLANCE REQUIREMENTS (Continued) l

e. At least once per 18 months by: 3,3
1. Verifying that the pressure drop across the ined HEPA filters and charcoal adsorber banks is less than 6 nches Water Gauge while operating the system at a flow rate of 2500 cfm i 105.
2. Verifying that on a recirculation signal, stem autos cally switches into a recirculation mode of operation with flow i through the HEPA filters and charcoal adsorber banks.

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1 MILLSTONE - UNIT 2 3/47-17a Amendment No. JJ 77, 199, JJJ, em lif,199. D5 C 0/ 9507140145 9507o7 DR ADOCK 0500 6

Oc tot >ar 29, 1990 PLANT SYSTEMS SURVEliLANCE REQUIREMENT (Continued)

3. V fying that control room air' in-leakage is less than 13 0 0 SCFM with the Control Air Conditioning System operating in t e recirculation / filtration mode.
f. After each complete or partial replacement of a HEPA filter bank by verifying that the HEPA filter banks remove greater than or equal to 99% of the DOP when they are tested in-place in accordance with ANSI M510-1975 while operating the system at a flow rate of 2500 cfm i 105.
g. After each complete or partial replacement of a charcoal adsorber bank by verifying that the charcoal adsorbers remove greater than or equal to 99% of a halogenated hydrocarbon refrigerant test gas when they are tested in-place in accordance with ANSI N510-1975 while operating the system at a flow rate of 2500 cfm i 10%.

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l MILLSTONE - UNIT 2 3/4 7-18 Amendment No. 7J,166,149 ODj

August 1.1975 PLANT SYSTEMS BASES 3/4.7.4 SERVICE WATER SYSTEM The OPERABILITY of the service water system ensures that sufficient cooling capacity is available for continued operation of vital components and Engineered Safety Feature equipment during nonnal and accident con-ditions. The redundant cooling capacity of this system, assuming a single failure, is consistent with the assumptions used in the accident analyses.  ;

3/4.7.5 FLOOD LEVEL The service water pump motors are normally protected against water damage to an elevation of 22 feet. If the water level is exceeding plant grade level i or if a severe storm is approaching the plant site, one service water pump motor will be protected against flooding to a minimum elevation of 28 feet to ensure that this pump will continue to be capable of removing decay heat from the reactor. In order to ensure operator accessibility to the intake structure action to provide pump motor protection will be initiated when the water level i

., reaches plant grade level.

3/4.7.6 CONTROL ROOM EMERGENCY VENTILATION SYSTEM The OPERABILITY of the control room emergency ventilation system ensures that 1) the ambient air temperature does not exceed the allowable temperature for continuous duty rating for the equipment and instrumentation  ;

cooled by this system and 2) the control room will remain habitable for  ;

operations personnel during and following all credible accident conditions. '

A The OPERABILITY of this system in conjunction with control room design provisions is based on limiting the radiation exposure to personnel occupying the control room to 5 rem or less whole body, or its equivalent.

This limi tion is consistent with the requirements of General Design

riteria of Appendix "A". 10 CFR 50.

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l MILLSTONE - UNIT 2 B 3/4 7-4 Ca'W l

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4 INSERT A The flow rate acceptance criteria of 2500 CFM i10 % ensures the system flow will be sufficiently close to the assumed design flow of 2500 CFM used in the radiological dose calculations. Although the dose  :

calculations use the nominal flow rate rather than the minimum acceptable flow rate of 2250 CFM, the ventilation flow rate used is acceptable because the ranges of flow fluctuation are overwhelmed by other conservatisms found in the control room dose calculation methodology. These conservatisms assure that the dose in the control room would in fact be below the 10 CFR 50 Appendix A GDC 19 limits even at the lowest flow rates allowed by the technical specification. Thus even at these lower flow rates the ventilation system is operable because it is capable of performir is safety function.

Currently there are sorm :ituations where the control room emergency ventilation (CREV) system cannot be depended upon to auto start on an accident signal, without operator action. Under most situations, the emergency filtration fans will start and the CREV system will be in its' l accident line up. However, it is possible that upon a single mechanical ,

failure of a supply (F21 A,B) or exhaust (F31 A,B) fan, operator action will i

be required to return to a full train line up. Also, if a single emergency

' bus does not power up for one train of the CREV system, the opposite train filter fan will auto start, but the required supply and discharge fans ,

do not auto start. Therefore, operator action is required to establish the whole train line up. This action is specified in the corresponding EOPs.

Because of this possibility the GDC 19 corresponding control room habitability radiological dose calculations don't take credit for CREV system clean up action until 10 minutes into the accident to allow for operator action.

When the system is checked to shift to " recirculation," this will be performed from the " normal" mode. The smoke purge exhaust dampers will not be tested to shut, as they are normally shut )

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4 Docket No. 50-336 B15252

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Attachment 2 Millstone Nuclear Power Station, Unit No. 2 Proposed Revision to Technical Specifications Control Room Emergency Ventilation System Retyped Pages l

July 1995

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PLANT SYSTENS SURVEILLANCE REQUIREMENTS (Continued)

e. At least once per 18 months by:
1. Verifying that the pressure drop across the combined HEPA filters and charcoal adsorber banks is less than 3.4 inches Water l Gauge while operating the system at a flow rate of 2500 cfm i 10%.
2. Verifying that on a recirculation signal, with the control room ventilation system operating in the normal mode, the system automatically switches into a recirculation mode of operation with flow through the HEPA filters and charcoal adsorber banks.

MILLSTONE - UNIT 2 3/4 7-17a Amendment No. 75,17,199,JJJ.

o201 Jil,Jff,Jll

- . . . _ . ..= . - .. . -_ .-

PLANT SYSTEMS ,

SURVEILLANCE REQUIREMENTS (Continued)

3. Verifying that control room air in-leakage is less than 130 SCFM with the Control Air Conditioning System operating in l the recirculation / filtration mode.
f. After'each complete or partial replacement of a HEPA filter bank by verifying that the HEPA filter banks remove greater than or equal to 99% of the D0P when they are tested in-place in accordance with ANSI N510-1975 while operating the system at a flow rate of 2500 cfm-1 10%.
g. After each complete or partial replacement of a charcoal absorber bank by verifying that the charcoal absorbers remove greater than or equal to 99% of a halogenated hydrocarbon refrigerant test gas when they are tested in-place in accordance with ANSI N510-1975 while operating the system at a flow rate of 2500 cfm i 10%.

Y NILLSTONE - UNIT 2 3/4 7-18 Amendment No. 77, #7, J#,

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4 PLANT SYSTEMS BASES

3/4.7.4 SERVICE WATER SYSTEM The OPERABILITY of the service water system ensures that sufficient cooling capacity is available for continued operation of vital components and j Engineered Safety Feature equipment during normal and accident conditions. The i redundant cooling capacity of this system, assuming a single failure, is consistent with the assumptions used in the accident analyses.

3/4.7.5 FLOOD LEVEL

, The service water pump motors are normally protected against water damage to an elevation of 22 feet. If the water level is exceeding plant grade level  ;

or if a severe storm is approaching the plant site, one service water pump motor will be protected against flooding to a minimum elevation of 28 feet to ensure that this pump will continue to be capable of removing decay heat from ,

i the reactor. In order to ensure operator accessibility to the intake structure action to provide pump motor protection will be initiated when the water level reaches plant grade level.

3/4.7.6 CONTROL ROOM EMERGENCY VENTILATION SYSTEM The OPERABILITY of the control room emergency ventilation system ensures that 1) the ambient air temperature does not exceed the allowable ,

temperature for continuous duty rating for the equipment and instrumentation cooled by this system and 2) the control room will remain habitable for operations personnel during and following all credible accident conditions.

The flow rate acceptance criteria of 2500 cfm i 10% ensures the system flow will ,

be sufficiently close to the assumed design flow of 2500 cfm used in the radiological dose calculations. Although the dose calculations use the nominal flow rate rather than the minimum acceptatle flow rate of 2250 cfm, the ventilation flow rate used is acceptable because the ranges of flow fluctuation are overwhelmed by other conservatisms found in the control room dose calculation methodology. These conservatisms assure that the dose in the control room would in fact be below the 10 CFR 50 Appendix A GDC 19 limits even at the lowest flow rates allowed by the technical specification. Thus even at these lower flow rates the ventilation system is operable because it is capable of performing its safety function.

i Currently there are some situations where the control room emergency ventilation (CREV) system cannot be depended upon to auto start on an accident signal, without operator action. Under most situations, the emergency filtration fans will start and the CREV system will be in its accident lineup. However, it is possible that upon a single mechanical failure of a supply (F21A, B) or  :

exhaust (F31A, B) fan, operator action will be required to return to a full train '

lineup. Also, if a single emergency bus does not power up for one train of the CREV system, the opposite train filter fan will auto start, but the required supply and discharge fans do not auto start. Therefore, operator action is required to establish the whole train lineup. This action is specified in the corresponding E0Ps.

MILLSTONE - UNIT 2 B 3/4 7-4 Amendment No.

0202 1 i

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1 PLANT SYSTEMS BASES 3/4.7.6 CONTROL ROOM EMERGENCY VENTILATION SYSTEM (continued)

Because of this possibility, the GDC 19 corresponding control room habitability radiological dose calculations do not take credit for CREV system clean-up action until 10 minutes into the accident to allow for operator action.

When the system is checked to shift to " recirculation," this will be performed from the " normal" mode. The smoke purge exhaust dampers will not be tested to shut, as they are normally shut.

The OPERABILITY of this system in conjunction with control room design provisions is based on limiting the radiation exposure to personnel occupying the control room to 5 rem or less whole body, or its equivalent.

This limitation is consistent with the requirements of General Design Criteria 19 of Appendix "A",10 CFR 50. l l

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MILLSTONE - UNIT 2 B 3/4 7-4c Amendment No.

0202

I f Docket No. 50-336 B15252 i

Attachment 3 billstone Nuclear Power Station, Unit No. 2 Proposed Revision to Technical Specifications Control Room Emergency Ventilation System Control Room Dose Calculations I

July 1995

TABLE 1 urtYETONE UNIT NO 2 CONTROL ROOM ASSUMPTIONS Descriotion Applicable Accidents

1. Control room volume 6.6 E04 ft 3 All
2. Maximum Outside Supply Fan Flow Rate Prior All to isolation = 800 cfm
3. Recirculation Flowrate through Charcoal All Filters = 2,500 cfm
4. Time at which recirculation starts through All filters = 10 minutes
5. Time at which recirculations through filters ends = 30 minutes MP1 MSLB

= 720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br /> MP2, MP3 LOCA

6. Unfiltered in-leakage rate = 130 cfm All
7. Filter efficiency = 90 percent (all forms of Iodine) All
8. Time for control room to isolate = 0.0 see MP2 LOCA

= 23.1 sec MP1 MSLB, MP3 LOCA

9. Control room X/Qs from a MP3 LOCA for MP3 LOCA releases from Containment and3 vent Time Period X/Os feec/m) 0-8 hours 4.78 E-04 8-24 hours 3.29 E-04 24-96 hours 1.20 E-04 96-720 hours 2.26 E-05
10. Control Room X/Qs for a MP2 LOCA, HP2 LOCA (High wind High wind speed case speed case Time Period X/Os feec/m 3) 0-36 hours 9.14 E-05
11. Respirators in use from 15 minutes to 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> MP-1 MSLB
12. Control Room X/Qs from a MP2 LOCA, MP2 LOCA (Low wind Low wind Speed Case (Containment release) speed case) 3 Time Period X/Os (sec/m) 0-1 hour 2.69 E-03
13. Control Room X/Qs from a MP1 MSLB MP1 MSLB 3

Time Period X/Os (sec/m) 0-1 hour 4.43 E-02

14. Control Room Purged at 1,000 cfm MP1 MSLB
15. Start of Purge Time = 30 minutes MP1 MSLB

TABLE 2 DOSE TO MILLSTONE UNIT 2 CONTROL ROOM OPERATORS REM ACCIDENT THYROID WHOLE BODYm SKIN (LIMIT = 30) (LIMIT = 5) (LIMIT = 30)

ZEAR HEH ISAR HEN ISAB EXE MP1 MSLB 26.2 25.2 0.42 0.39 5.9 6.2 MP2 LOCA- 9.3 11.1 0.95 0.95 0.2 0.3 LOW WIND MP2 LOCA- 26.2 25.2 0.94 0.95 0.2 0.3 HIGH WIND MP3 LOCA 24.8 10.3 0.21* 2.40 2.7 8.2 (1) Includes both shine dose from outside sources and submersion dose from activity in Control Room.

(2) Shine dose from sources outside the control room were not included in original MP3 LOCA dose to MP2 control room. For comparison, for new calculation, dose from submersion is 0.50 REM.

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