ML20045B543

From kanterella
Jump to navigation Jump to search
Proposed TS 3/4.6.1.3, Containment Airlocks.
ML20045B543
Person / Time
Site: Beaver Valley
Issue date: 06/10/1993
From:
DUQUESNE LIGHT CO.
To:
Shared Package
ML20045B542 List:
References
NUDOCS 9306180053
Download: ML20045B543 (8)
v • d • e


Text

- . . . .- . - . . .-

I DPR-66 3/4.6 CONTAINMENT SYSTEMS 1

BASES 'I l

3/4.6.1 PRIMARY CONTAINMENT i 3/4.6.1.1 CONTAINMENT INTEGRITY l l

Primary CONTAINMENT INTEGRITY ensures that the release of radioactive i 1 materials from the containment atmosphere will be restricted to those  ;

I leakage paths and associated leak rates assumed in the accident

) analyses. This restriction, in conjunction with the leakage rate ,

limitation, will limit the site boundary radiation doses to within the limits of 10 CFR 100 during accident conditions.  !

3/4.6.1.2 CONTAINMENT LEAKAGE f

The limitations on containment leakage rates ensure that the total containment leakage volume will not exceed the value assumed in the  ;

accident analyses at the peak accident pressure, Pa. As an added  :

conservatism, the measured overall integrated leakage rate is further ,

limited to s 0.75 La during performance of the periodic test to I account for possible degradation of the containment leakage barriers  ;

between lea. age tests.

The surveillance testing for measuring leakage rates are consistent with the requirements of Appendix "J" of 10 CFR 50. l The exemption to 10 CFR 50 Appendix J.III.D.1(a) allows Type A tests i to be conducted on a 40 i 10-month schedule, not in conjunction with 1

~

any ISI tests.

3/4.6.1.3 CONTAINMENT AIR LOCKS l I

The limitations on closure and leak rate for the containment air  ;

locks are required to meet the restrictions on CONTAINMENT INTEGRITY l and containment leak rate. Surveillance testing of the air lock ,

4 seals provides assurance that the overall air lock leakage will not  :

become excessive due to seal damage during the intervals between air i lock leakage tests. Only one closed door in each air lock is i required to maintain the integrity of the containment.

An allowance has been provided for passage through the-containment air lock (s) when one air lock door in one or more air locks is ,

inoperable. A footnote provides entry and exit through the operable locked closed outer air lock door to perform repairs on the inner air i lock door. The outer air lock door is fully repairable from outside  !

of containment. Therefore, passage through an operable locked closed inner air lock door is not required. It is not intended that the air  :

lock would be used for anything other than repair activities during the period of time there is an inoperable air lock door.  !

}

BEAVER VALLEY - UNIT 1 B 3/4 6-1 Amendment No.

jProposed Wording) 9306180053 930610 7_7 PDR ADDCK 05000334 P PDR t_c.

1

. . j l

DPR-66 i CONTAINMENT SYSTEMS BASES 3/4.6.1.3 CONTAINMENT AIR LOCKS (Continued)

An allowance has also been provided for passage through the containment air lock (s) when an interlock mechanism is inoperable.

A footnote provides for unlocking and use of the air lock provided that an individual is stationed at the air lock, dedicated to assuring that at least one OPERABLE air lock door remains closed.

This allowance is provided to address those situations when use of an air lock with only an inoperable interlock mechanism may be preferred over use of the other air lock. Use of the equipment hatch emergency air lock for entry and exit of the containment remains an acceptable alternative when personnel safety cannot be guaranteed when the personnel air lock has an inoperable air lock door or interlock.

3/4.6.1.4 and 3/4.6.1.5 INTERNAL PRESSURE AND AIR TEMPERATURE The limitations on containment internal pressure and average air temperature as a function of river water temperature ensure that 1)-

the containment structure is prevented from exceeding its design negative pressure of 8.0 psia, 2) the containment peak pressure does not exceed the design pressure of 45 psig during LOCA conditions, and 3) the containment pressure is returned to subatmospheric conditions following a LOCA.

The containment internal pressure and temperature limits shown as a function of river water temperature describe the operational envelope that will 1) limit the containment peak pressure to less than its design value of 45 psig and 2) ensure the containment internal pressure returns subatmospheric within 60 minutes following a LOCA.

The limits on the parameters of Figure 3.6-1 are consistent with the assumptions of the accident analyses.

i 3/4.6.1.6 CONTAINMENT STRUCTURAL INTEGRITY This limitation ensures that the structural integrity of the containment vessel will be maintained comparable to the original design standards for the life of the facility. Structural integrity is required to ensure that the vessel will withstand the maximum pressure of 40.0 psig in the event of a LOCA. The visual and Type A leakage tests are sufficient to demonstrate this capability.

BEAVER VALLEY - UNIT 1 B 3/4 6-2 Amendment No.

(Proposed Wording) i

DPR-66 j CONTAINMENT SYSTEMS i i

BASES 3/4.6.2 DEPRESSURIZATIO?i AND COOLING SYSTEMS, i

3/4.6.2.1 and 3/4.6.2.2 CONTAINMENT OUENCH AND RECIRCULATION SPRAY I SYSTEMS l The OPERABILITY of the containment spray systems ensures that ,

containment depressurization and subsequent return to subatmospheric  ;

pressure will occur in the event of a LOCA. The pressure reduction l and resultant termination of containment leakage are consistent with l the assumptions used in the accident analyses. j 3/4.6.2.3 CHEMICAL ADDITION SYSTEM ,

i The OPERABILITY of the chemical addition system ensures that I sufficient NaOH is added to the containment spray in the event of a LOCA. The limits on NaOH minimum volume and concentration, ensure ,

that 1) the iodine removal efficiency of the spray water is  ;

maintained because of the increase in pH value, and 2) corrosion ,

effects on components within containment are minimized. These  !'

assumptions are consistent with the iodine removal efficiency assumed in the accident analyses.  ;

3/4.6.3 CONTAINMENT ISOLATION VALVES The OPERABILITY of the containment isolation valves ensures that the ,

containment atmosphere will be isolated from the outside environment in the event of a release of radioactive material to the containment

  • atmosphere or pressurization of the containment. Containment. t isolation within the time limits specified' ensures that the release i of radioactive material to the environment will be consistent with i the assumptions used in the analysis for a LOCA.  :

3/4.6.4 COMEUSTIBLE GAS CONTROL The OPERABILITY of the equipment and systems required for the  !

detection and control of hydrogen gas ensures that this equipment  !

will be available to maintain the hydrogen concentration within i containment below its flammable limit during post-LOCA conditions. '

Either recombiner unit is capable of controlling the expected .

hydrogen generation associated with 1) zirconium-water reactions,

2) radiolytic decomposition of water 3) corrosion of metals within containment. These hydrogen control systems are consistent with the  !

recommendations of Regulatory Guide 1.7, " Control of Combustible Gas l' Concentrations in Containment Following a LOCA."

i 1

1 BEAVER VALLEY - UNIT 1 B 3/4 6-3 Amendment No. '

(Proposed Wording) l

i DPR-66 CONTAINMENT SYSTEMS I

BASES 1

J 3/4.6.5 SUBATMOSPHERIC PRESSURE CONTROL SYSTEM >

k 3/4.6.5.1 STEAM JET AIR EJECTOR The closure of the manual isolation valves in the suction of the 4 1 steam jet air ejector ensures that 1) the containment internal'  !

pressure may be maintained within its operation limits by.the .

mechanical vacuum pumps and 2) the containment atmosphere is '

isolated from the outside environment in the event of a LOCA. These valves are required to be closed for containment isolation.  ;

?

i 4

e i

i t

I l

i i

t 5

l 4

i i

i I

i BEAVER VALLEY - UNIT 1 B 3/4 6-4 _

Amendment No.

(Proposed Wording) l

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

i NPF-73  !

3/4.6 CONTAINMENT SYSTEMS j i

i

' BASES l 3/4.6.1 PRIMARY CONTAINMENT '

3/4.6.1.1 CONTAINMENT INTEGRITY >

Primary CONTAINMENT INTEGRITY ensures that the release -of l radioactive materials from the containment atmosphere will be  ;

restricted to those leakage paths and associated leak rates assumed l in the accident analyses. This restriction, in conjunction with the ,

leakage rate limitation, will limit the site boundary radiation doses j to within the limits of 10 CFR 100 during accident conditions.

l 3/4.6.1.2 CONTAINMENT LEAKAGE j The limitations on containment leakage rates ensure that the total  !

containment leakage volume will not exceed the value assumed in the  !

accident analyses at the peak accident pressure, Pa. As an added l conservatism, the measured overall integrated leakage rate is further i limited to $ 0.75 La during performance of the periodic test to  !

account for possible degradation of the containment leakage barriers ,

between leakage tests. l; The surveillance testing for measuring leakage rates are  !

consistent with the requirements of Appendix "J" of 10 CFR 50.

3/4.6.1.3 CONTAINMENT AIR LOCKS i

The limitations on closure and leak rate for the containment air locks are required to meet the restrictions on CONTAINMENT INTEGRITY ,

and containment leak rate. Surveillance testing of the air lock seals i provides assurance that the overall air lock leakage'will not become excessive due to seal damage during the intervals between air-lock leakage tests. Only one closed door in each air lock is required to maintain the integrity of the containment.

An allowance has been provided for passage through the containment air lock (s) when one air lock door in one or more air locks is inoperable. A footnote provides entry and exit through the operable locked closed outer air lock door to perform repairs on the inner air i lock door. The outer air lock door is fully repairable from outside of containment. Therefore, passage through an operable locked closed inner air lock door is not required. It is not intended that the air I lock would be used for anything other than repair activities during the period of time there is an inoperable air lock door.

I J

BEAVER VALLEY - UNIT 2 B 3/4 6-1 Amendment No.

i (Proposed Wording)

l NPF-73 CONTAINMENT SYSTEMS BASES 3/4.6.1.3 CONTAINMENT AIR LOCKS (Continued)

An allowance has also been provided for passage through the containment air lock (s) when an interlock mechanism is inoperable. A footnote provides for unlocking and use of the air lock provided that an individual is stationed at the air lock, dedicated to assuring that at least one OPERABLE air lock door remains closed. This allowance is provided to address those situations when use of an air lock with only an inoperable interlock mechanism may be preferred over use of the other air lock. Use of the equipment hatch emergency air lock for entry and exit of the containment remains an acceptable alternative when personnel safety cannot be guaranteed when the personnel air lock has an inoperable air lock door or interlock.

3/4.6.1.4 and 3/4.6.1.5 INTERNAL PRESSURE AND AIR TEMPERATURE The limitations on containment internal pressure and average air temperature as a function of service water temperature ensure that 1) the containment structure is prevented from exceeding its design negative pressure of 8.0 psia, 2) the containment peak pressure does not exceed the design pressure of 45 psig during LOCA conditions, and

3) the containment pressure is returned to subatmospheric conditions  !

following a LOCA. l l

The containment internal pressure and temperature limits shown as l a function of service water temperature describe the operational envelope that will 1) limit the containment peak pressure to less than its design value of 45 psig and 2) ensure the containment internal pressure returns subatmospheric within 60 minutes following a LOCA. Additional operating margin is provided if the containment average air temperature is maintained above 100*F as shown on Figure 3.6-1.

The limits on the parameters of Figure 3.6-1 are consistent with the assumptions of the accident analyses.

3/4.6.1.6 CONTAINMENT STRUCTURAL INTEGRITY This limitation ensures that the structural integrity of the containment vessel will be maintained comparable to the original design standards for the life of the facility. Structural integrity is required to ensure that the vessel will withstand the maximum pressure of 44.7 psig in the event of a LOCA. The visual and Type A 1 leakage tests are sufficient to demonstrate this capability.

BEAVER VALLEY - UNIT 2 B 3/4 6-2 Amendment No.

(Proposed Wording)

. . . __ . _ - --. ... - ~ ~ - _ ..

NPF-73 l 3/4.6 CONTAINMENT SYSTEMS BASES 3/4.6.2 DEPRESSURIZATION AND COOLING SYSTEMS

{

3/4.6.2.1 and 3/4.6.2.2 CONTAINMENT OUENCH AND RECIRCULATION SPRAY-SYSTEMS The OPERABILITY of the containment spray systems ensures that containment depressurization and subsequent return to subatmospheric pressure will occur in the event of a LOCA. The pressure reduction and resultant termination of containment leakage are consistent with i the assumptions used in the accident analyses.  ;

3/4.6.2.3 CHEMICAL ADDITION SYSTEM l a

The OPERABILITY of the chemical addition system ensures that sufficient NaOH is added to the containment spray in the event of a LOCA. The limits on NaOH minimum volume and concentration, ensure  ;

that 1) the iodine removal efficiency of the spray water is j maintained because of the increase in pH value, and 2) corrosion effects on components within containment are minimized. These  !

assumptions are consistent with the iodine removal efficiency assumed in the accident analyses.  ;

I

! 3/4.6.3 CONTAINMENT ISOLATION VALVES _l 1 I 3

The OPERABILITY of the containment isolation valves ensures that I the containment atmosphere will be isolated from the outside L environment in the event of a release of radioactive material to the i containment atmosphere or pressurization of the containment. i Containment isolation within the time limits specified ensures that the release of radioactive material to the environment will be consistent with the assumptions used in the analyses for both a LOCA  ;

and major secondary system breaks.  !

3/4.6.4 COMBUSTIBLE GAS CONTROL The OPERABILITY of the equipment and systems required for the f detection and control of hydrogen gas ensures that this equipment l will be available to maintain the hydrogen concentration within  !

containment below -its flammable limit during post-LOCA conditions. l Either recombiner unit is capable of controlling the expected  !

hydrogen generation associated with 1) zirconium-water reactions, 2)  !

radiolytic decomposition of water, and 3) corrosion of metals within '

containment. These hydrogen control systems are consistent with the l recommendations of Regulatory Guide 1.7, " Control of Combustible Gas '

Concentrations in Containment Following a LOCA."

BEAVER VALLEY - UNIT 2 B 3/4 6-3 Amendment No.

(Proposed Wording)

, i

I NPF-73~  !*

3/4.6 CONTAINMENT SYSTEMS BASES ,

3/4.6.5 SUBATMOSPHERIC PRESSURE CONTROL SYSTEM 3/4.6.5.1 STEAM JET AIR EJECTOR The closure of the manual isolation valves in the suction of the i

steam jet air ejector ensures that 1) the containment internal pressure may be maintained within its operation limits by the mechanical vacuum pumps and 2) the containment atmosphere is isolated from the outside environment in the event of a LOCA. These valves are required to be closed for containment isolation.  ;

l l

i I

I i

i BEAVER VALLEY - UNIT 2 B 3/4 6-4 Amendment No.

(Proposed Wording) l

Retrieved from "https://kanterella.com/w/index.php?title=ML20045B543&oldid=2557108"