ML20100H774

Proposed Tech Specs,Proposing to Revise TS 3.6.5.1, Drywell, to Allow Drywell Bypass Leakage Tests to Be Performed at Intervals of Up to Ten Yrs Based on Demonstrated Performance of Drywell Barrier

ML20100H774
Person / Time
Site:	Clinton
Issue date:	02/22/1996
From:	ILLINOIS POWER CO.
To:
Shared Package
ML20100H766	List: ML20100H774 U-602549, Application for Amend to License NPF-62,proposing to Revise TS 3.6.5.1, Drywell, to Allow Drywell Bypass Leakage Tests to Be Performed at Intervals of Up to Ten Yrs Based on Demonstrated Performance of Drywell Barrier
References
NUDOCS 9602280039
Download: ML20100H774 (32)

Text

_ . . _ . . _ . _. _ ._.. _ . . ._ . .. . _ . _ _ . _ . _ . .

e  :

Attachment 3 ,

to U-602549  ;

LS-%-001 .

Page1of10 8

t

)

i 2- ,

4 t

i  !

Attached Marked-Up Pages of the Technical Specifications  ;

t i ,

4 4

I e

f i

i

~

4 4-'

i

+

)

m 4

3 b

', k 9602290039 960222 PDR ADOCK 05000461 '

P PDR

_ ,-c ,- _ - , - - - - - , -,

I Attechm2nt. 3 to 11-662549'~

ts.96-001 Page 2 of 10 Drywel.1 3.6.5;l l

'3.6 CONTAINMENT SYSTEMS 3.6.5.1 Drywell LCO 3. 6. '5.1 The drywell shall be OPERA 8LE.

APPLICABILITY: MODES 1, 2, and 3. l ACTIONS REQUIRED ACTION COMPLETION TIME CONDITION i

r A. Drywell inoperable. ' A.1 Restore drywell to I hour OPERABLE status.-  ;

t B. Required Action and B.1 Be in MODE 3. 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />  !

associated Completion Time not met. AND B.2 Be in MODE 4. 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> i

SURVEILLANCE REQUIREMENTS SURVEILLANCE . FREQUENCY

[

SR 3.6.5.1 --- ------- OTE---- --------- -------- ,

N requir to ba rformed til entry nto MODE on th first uni startup g

~

1 from th sixth r

_______________/__uelingo age. ,

2MT 2.co-SH 6 j y i Verify bypass leakage .is less than or [IO:::th:) l equal to the bypass leakage limit.

However, during the first unit startup gg following bypass leakage testing 3*0-M Aa 1 performed in accordance with this SR, the- ,

acceptance criterion is s 10% of the t

.drywell bypass leakage limit.

i

-(continued)

CLINTON 3.6-54 AmendmentNo.g,p6

Attcchsent 3 to U-602549

• - LS-96-001 '

~*

.Paga 3 of 10 .

INSERT 3.6-54A' 24 months following 2  ;

consecutive tests with -

bypass leakage greater than the bypass leakage limit until 2 consecutive tests are less than or  ;

equal to the bypass leakage limit E

48 months following a  !

test with bypass leakage greater than the bypass leakage limit E

.........--N0TE----------

SR 3.0.2 is not applicable for extensions

> 12 months.

120 months INSERT 3.6-54B

. SR 3.6.5.1.1 Perform leakage rate test for each Once within ,

drywell air lock door seal by 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> 4 pressurizing the gap between the after each 4 door seals to a 3.0 psig. drywell air lock door  :

closing 4

4 SR 3.6.5.1.2 ---------------NOTE---------------

- An inoperable air lock door does not invalidate the previous successful performance of the overall drywell air lock leakage rate test. ,

d Perform overall drywell air lock 24 months  :

leakage rate test at > 3.0 psig.

4 E

Attcchment 3 to U-602549 LS-96-001

.Page 4 of 10 Drywell) 3.6.5.1 -

1 SURVEILLANCE REQUIREMENTS (continued)

SURVEILLANCE -

FREQUENCY Once pf-lor to SR 3.6.5.1/4 Visually inspect the exposed accessible each Type A l

. interior and exterior surfaces of the drywell . test required by SR 3.6.1.1.1.

i CLINTON 3.6-55 Amendment No. p6'

Attcchment 3 to U-602549 l LS-96-0

- Paga 5 10 rywell Air Leck 3.6.5.2 l

?

l 3.6 CONTAINMENT SYSTEMS 3.6.5.2 Drywell Air Lock LCO 3.6.5.2 The drywell air lock shall be OPERABLE.

APPLICABILITY: MODES 1, 2, and 3.

ACTIONS

---

NOTE-------------------------------------

Entry and exit is permissible to perform repairs of the affected air lock

, components.

4 f 2. er appl able Condi ons and Require Actions of LC0 .6.5.1,

- Drywell when air ck leakage resul s in exceeding verall drywel (s_ bypass akaae rate acceptance crite a.

(continued) i

{

d L

CLINTON 3.6-56 Amendment No. jHf

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

Attachs.snt 3 to U-602549 h!h6Of10 Drywell Air Lock 3.6.5.2 l

ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME l

C. Drywell air lock C.1 nitia action o IJumediaj41y inoperable for reasons eval te dryw 1 / /

other than Condition A ov all lea gerate/  !

or B. p LCO 3 rywell

.5.1,.

using

/

curren air loc est resu s. j G4- Verify a door is I hour closed.

AND i C./ 2. Restore air lock to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> OPERABLE status. ,

D. Required Action and 0.1 Be in MODE 3. 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> associated Completion i Time not met. AND 1 D.2 Be in MODE 4. 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> i

i

l l

l ll 1

CLINTON 3.6-59 Amendment No. jMI

)

1

Attechasnt 3 to U-602549

~

• LS-96-001 Page 7 of 10 Drywell Air Lock 3.6.5.2 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY

~

n<4< m t ea rote-Wst & cuh ar SR 3.6.5./.'l 9' . '. '. ., ...I.D. . . .E. .N. .E'#*D.

m - ..- " . . .. . _E.

. Onee*' within M. . ".

72 . . "..pi the gap between the door seals hours after each drywell g pre:= H nd to a 3.0 psig.

j g air lock door 6 *;4 6 closing SR 3.6.5. 7) ------------------NOTE-------------------

Only required to be performed upon entry Into drywell.

Verify only one door in the drywell air months

lock can be opened at a time.

I .q. ' y SR 3. 6. 5. ih+ ------------------NOTfJ------------------

Jt" An inoperable air lock door does not invalidate the previous successful

_- performance of the overal14 air lock

. leakageltest. Qate) g Q '2. Prior o perf air ock le age te ance the ov all) at 2 3 psig h a o shall e press rized C'Rwfo<@r 24 Jer;rygverall drywell air lock leakage .18 months rate is ; 2 scfh by pcrfer;;;ir; ar, ever:11

. .m i_o i-_o___

test at h 3 0 psig*

l CLINTON 3.6-60 Amendment No. g

l Attechm2nt 3 to U-602549 l . LS-96-001 Page 8 of 10 Drywell Isolation Valves i 3.6.5.3 3.6 CONTAINMENT SYSTEMS 3.6.5.3 Drywell Isolation Valves LCO 3.6.5.3 One drywell isolation valve in each drywell penetration flow path shall be OPERABLE, except for the drywell vent and purge penetrations in which two drywell isolation valves shall be OPERABLE.

---

NOTE-----------------------------

This LC0 does not apply to OPERABILITY of Drywell Post-LOCA Vacuum Relief System valves.

APPLICABILITY: N00ES 1, 2, and 3.

ACTIONS

.....................................N0TES------------------------------------

1. Penetration flow paths, except the 10 inch, 24 inch, and 36 inch drywell vent and purge penetration flow paths may be unisolated intermittently under administrative controls.

2. Separate Condition entry is allowed for each penetration flow path. )

3. Enter applicable Conditions and Required Actions for systems made inoperable by drywell isolation valves.

P4. nter aplicabl Conditi s and Re ired Acti s of LC0 .6.5.1, "Drywg)1," wh drywell isolation alve leak e result in excee ng 1

(~_ overM1 dryw 1 bypas leakage r te accept ce criter a.

(continued) l l

CLINTON 3.6-61 AmendmentNo.JPs  ;

-m-m_

Attecha:nt 3 to U-602549 LS-96-001 No chages.7tevl8e/ Pass 9 of 10 h CoyvMnu% on%, Drywell Isolation Valves 3.6.5.3 SURVEILLANCE REQUIREMENTS I

SURVEILLANCE FREQUENCY i SR 3.6.5.3.1 Verify each 24 inch drywell vent and 31 day's purge supply isolation valve is sealed closed.

SR 3.6.5.3.2 ------------------NOTE-------------------

Not required to be met when the 36 inch 4

and either the 10 inch or 24 inch drywell vent and purge exhaust valves are open for pressure control, ALARA or air quality considerations for personnel entry. Also not required to ha met during Surveillances or special testing of the purge system that requires the valves to be open. The drywell vent and purge exhaust valves shall not be opened with a 12 inch or 36 inch primary containment purge system rupply or

< exhaust line open.

Verify each 10 inch, 24 inch, and 36 inch 31 days drywell vent and purge exhaust isolation valve is closed.

(continued) i CLINTON 3.6-64 .,

Amendment No. 95

Attschment 3 to U-602549 l

% ha e6.$rou Mek Dhe1}o Is d1Nicn Valvas  :

f CCfY O V h O , 3.6.5.3- ,

SURVEILLANCE REQUIREMENTS (continued)

SURVEILLANCE FREQUENCY J

SR 3.6.5.3.3 ------------------NOTES----------- ----- -

1. Valves and blind flanges in high radiation areas may be verified by use of administrative means.

2. Not required to be met for drywell  ;

isolation valves that are open under ,

administrative controls.

Verify each required drywell isolation Prior to manual v3 1 ve and blind flange that is entering MODE 2 required to be closed during accident or 3 from conditions is closed. MODE 4, if not performed in ,

the previous 92 days s SR 3.6.5.3.4 Verify the isolation time of each In accordance  ;

required power operated and each required with the i automatic drywell isolation valve is Inservice within limits. Testing Program

+

SR 3.6.5.3.5 Verify each required automatic drywell 18 months isolation valve actuates to the isolation position on an actual or simulated isolation signal.

r, i CLINTON 3.6-65 ., Amendment No. 95

Attachment 4 to U-602549 LS-96-001 Page1 of22 Technical Specification Bases Changes

Attachmnt 4 to U-602549

• LS-96-001

' ~

Pags 2 of 22  :

Drywell  ;

B 3.6.5.1 a

4 B 3.6 CONTAINMENT SYSTEMS '

. 8 3.6.5.1 Drywell ,

BASES d

8ACKGROUND The drywell houses the reactor pressure vessel (RPV), the i

reactor coolant recirculating loops, and branch connections of the Reactor Cochnt System (RCS), which have isolation  ;

valves at the primary containment boundary. The function of the drywell is to maintain a pressure boundary that channels >

steam from a loss of coolant accident (LOCA) to the

- suppression pool, where it is condensed. Air forced from the drywell is released into the primary containment through i , the suppnession pool. The pressure suppression capability of the suppression pool assures that peak LOCA temperature 4

and pressure in the primary containment are within design i limits. The drywell also protects accessible areas of the containment from radiation originating in the reactor core 4 . and RCS.

To ensure the,drywell pressure suppression capability, the

' drywell. bypass leakage must be minimized to prevent overpressurization-of the primary containment during the drywell pressurization phase of a LOCA. This requires periodic testing of the drywell bypass leakage, confirmation

. that the drywell air lock is leak tight, OPERABILITY of the drywell isolation valves, and confirmation that the drywell j

Tcgstr

) vacuum relief valves are closed.

j g,u- 102. A -

5he isolation devices for the drywell penetrations are a part of the drywell barrier. To maintain this barrier:

i l

a. The drywell air lock is OPERABLE except as provided in LCO 3.6.5.2, "Drywell Air Lock";

b. The drywell penetrations required to be closed during accident conditions are either:

i I 1. capable of being closed by an OPERABLE automatic drywell isolation valve, or

2. closed by a manual valve, blind flange, or de-activated automatic valve secured in the closed position except as provided in LCO 3.6.5.3, "Drywell Isolation Valves";

(continued)

l

~

CLINTON B 3.6-102 RevisionNo./ f l

l i l

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

Attachment 4 to U-602549

• LS-96-001 Page 3 of 22 6

INSERT B 3.6-102A The drywell air lock forms cart of the drywell pressure boundary.  !

Not maintaining air lock OPERABILITY may result in degradation of the  !

pressure suppression capability, which is assumed to be functional in the unit safety analyses. The drywell air lock does not need to meet the requirements of 10 CFR 50. @pendix J (Ref. 2), since it is not part of the primary containment leakage boundary. . However, it is prudent to specify a leakage rate requirement for the drywell air lock. A seal leakage rate limit and an air lock overall leakage rate limit have been established to assure the integrity of the seals.

i i

r

Attcchment 4 to U-602549 s

\p j 22 Drywell kOrdVQes.

conWywly .

DIN B 3.6.5.1 CASES

c. All drywell equipment hatches are closed; l BACKGROUND (continued) The Drywell Post-LOCA Vacuum Relief System is d.

OPERABLE except as provided in LCO 3.6.5.6, "Drywell Post-LOCA Vacuum Relief System";

l

e. ThesuppressionpoolisOPERABLE,exceptasprovided in LCO 3.6.2.2, " Suppression Pool Water Level"; and

f. The drywell leakage. rate is within the liinits of this LCO.

This Specification is intended to ensure that the performance of the drywell in the event of a DBA meets the assumptions used in the safety analyses (Ref.1).

Analytical methods and assumptions involving the drywell are

APPLICABLE The safety analyses assume that SAFETY ANALYSES presented in Reference 1.

for a high energy line break inside the drywell, the steam is directed to the suppression pool through the horizontal Maintaining the pressure vents where it is condensed.

suppression capability assures that safety analyses remain valid and that the peak LOCA temperature and pressure in the primary containment are within design Ifmits.

The drywell satisfies Criteria 2 and 3 of the NRC Policy Statement.

LCO Maintaining the drywell OPERABLE is required to ensure that the pressure suppression design functions assumed in the safety analyses are met. The drywell is OPERABLE if the drywell structural integrity is intact and the bypass leakage is within limits, except prior to the first startupAt after performing a required drywell bypass leakage test.

this time, the drywell bypass leakage must be s 10% of the drywell bypass leakage limit.

APPLICABILITY In MODES 1, 2, and 3, a DBA could cause a release of radioactive material to the primary containment. In MODES 4 and 5, the probability and consequences of these events are reduced due to the pressure and temperature limitations of these MODES. Therefore, the drywell is not required to be OPERABLE in MODES 4 and 5.

(continued) l 8 3.6-103 Revision No. M  !

CLINTON

6

. Attachment'4 to U-602549 Ls-96-001 Page 5 of 22 Drywell B 3.6.5.1  :

. l BASES '(continued).

ACTIONS A.1 In the event the drywell 'is inoperable, it must be restored to OPERABLE status within I hour. The 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> Completion  :

Time provides a period of time to correct the problem commensurate with the importance of maintaining the drywell i OPERABLE during MODES 1, 2, and 3. This time period also~

ensures that the probability of an accident (requiring i i

drywell OPERABILITY) occurring during periods.when the j

drywell is inoperable is minimal.. Also, the Completion Time '

is the same as that applied to inoperability of the primary containment in LCO 3.6.1.1, " Primary Containment." ,

i

)

B.1 and B.2 -

.If the drywell cannot be restored to OPERABLE status within the required Completion Time, the plant must be brought to a  !

MODE in which the LCO does not apply. To achieve this  :

status, the plant must be brought to at least MODE.3 within -

12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and to MODE 4 within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />. The allowed l Completion Times are reasonable, based on operating experience, to reach the required plant conditions from full power conditions in an orderly manner and without 1 challenging plant systems.  ;

I

& j 3.6.5.

SURVEILLANCE SR l

REQUIREMENTS

-, The analyses in Reference 1 are based on a maximum drywell l pgr < bypass leakage. This Surveillance ensures that the actual

- drywell bypass leakage is less than or 8equal to the ,

M' acceptable A4 design value of 1.18 ft assumed in the safety analysis. ' As left drywell bypass leakage, prior to the first startup after performing a required drywell bypass  ;

leakage test, is required to be s 10% of the drywell bypass leakage limit. At all other times between required drywe  :

I leakage rate tests, the acceptance criteria is based o % e.

design A M . At the design A 4 the containment l temperature and pressurization response are bounded by the  :

. assumptions of the safety analysis.' One drywell air lock door is left open during each drywell bypass leakage test such that each drywell air lock door is leak tested during i at least every other drywell bypass leakage test. This )

ensures that the leakage through the drywell air lock is 1 i

(conti'nued)

' j

.. i l CLINTON B 3.6-104 Revision No. g

Attachment 4 to U-602549 LS-96-001 Pegs 6 of 22 i 4 F i- INSERT B 3.6-104A i SR 3.6.5.1.1

)

- This SR requires a test be performed to verify seal leakage of the drywell air lock doors at pressures 2 3.0 psig. A seal leakage rate '

limit of s 2 scfh has been established to ensure the integrity of the seals. The Surveillance is only required to be performed once within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> after each closing. The Frequency of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> is based on.

operating experience.

SR 3.6.5.1.2 K

This SR requires a test to be )erformed to verify overall air lock leakage of the drywell air loct at pressures a 3.0 psig. Prior to performance of this test, the air. lock must be pressurized to 19.7 i psid. This differential pressure is the assumed peak drywell ,

pressure expected from the accident analysis. Since the drywell -

pressure rapidly returns to a steady state maximum differential '

pressure of 3,0 psid (due to suppression pool vent clearing), the

- overall air lock leakage is allowed to be measured at this pressure.

'An overall air lock leakage limit of s 2 scfh has been established to

ensure the integrity of the seals. The 24-month Frequency is based

~

on the need to perform this Surveillance under the conditions that apply during a plant outage and the potential for violating the  !

drywell boundary, Operating experience has shown these components t usually pass the Surveillance. Therefore, the Frecuency was concluded to be acceptable from a reliability stancpoint.

This SR has been modified by a Note indicating that an inoperable air ,

lock door does not invalidate the previous successful performance of l

^

an overall air lock leakage test. This is considered reasonable, i since either air lock door is capable of providing a fission product I barrier in the event of a DBA.

i I -

l

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

Attachmsnt 4 to U-602549

- LS-96-001 Page 7 of 22 Drywell B 3.6.5.1

BASES SURVEILLANCE SR 3.6.5. (continued)

U g ,

REQUIREMENTS properly accounted for in the measured bypass leakace and that each air lock is tested Deriodically. [Ihe leaka testl ith the d ficulty

is perfo d every 18 months, consisten lation exp ure, and

( of per raing-the est, risk f high r; ,

the r note possi lity tha a compon failure at is not ggg ide ified by me other ywall or rimary co ainment SR

'E34-05AJ m ht occur. Operating xperienc has shown at these /

t ponents sually pa the Sur illance n performed (t

( 7 the 18 th Freque y. Ther ore, the equency was conclud to be a eptable om a reli 111ty standp nt.

In ad tion, if to cons tive tes fail to meet e lea ge limit, test all be per rmed at least very 9 mon hs uhtil wo con cutive test meet the lim , at which utime the 18 month Freauency may be resumed. J SR 3.6.5.1 The exposed accessible drywell interior and exterior

- surfaces are inspected to ensure there are no apparent i

physical defects that would prevent the drywell from i

performing its intended function. This SR ensures that drywell structural integrity is maintained. The frequency

- was chosen so that the interior and exterior surfaces of the

' -drywell can be inspected in conjunction with the inspections of the primary containment required by 10 CFR 50, Appendix J (Ref.2). Due to the passive nature of the drywell structure, the specified Frequency is sufficient to identify j component degradation that may affect drywell structural integrity.

l REFERENCES 1. USAR, Chapter 6 and Chapter 15.

2. 10 CFR 50, Appendix J.

l CLINTON B 3.6-105 Revision No. J/f 1

I

Attcchment 4 to U-602549 i Ls-96-001 Pags 8 of 22 ,

INSERT B 3.6-105A

~

r This Surveillance is performed at least once every 10 years (120 months) on a performance based frequency. The Frequency is ,

consistent with the difficulty of performing the test. risk of high  :

radiation exposure, and the remote possibility that sufficient t component failures will occur such that the drywell bypass leakage ,

limit will be exceeded. If during the performance of this required  !

Surveillance the drywell bypass leakage is greater than the leakage limit, the Surveillance Frequency is increased to at least once every  ;

48 months. If during the performance of the subsequent consecutive Surveillance the drywell bypass leakage is less than or equal to the drywell bypass leakage limit. the 10-year Frequency may be resumed. ,

If during the performance of the subsequent consecutive Surveillance the drywell bypass leakage is greater than the drywell bypass leakage limit. the Surveillance Frequency is increased to at least once every 24 months. The 24-month Frequency must be maintained until the drywell bypass leakage is less than or equal to the leakage limit during the performance of two consecutive Surveillances, at which t time the 10-year Frequency may be resumed. For two Surveillances to be considered consecutive. the Surveillances must be performed at least 12 months apart.

Since the Frequency is performance based. the Frequency was concluded to be acceptable from a reliability standpoint. -

i

)

l l

i l

I

Attachment 4 to U-602549

LS-96-001 8* NyNil' Air' Lock B 3.6.5.2 8 3.6 CONTAINMENT. SYSTEMS 8 3.6.5.2 Drywell Air Lock BASES

. BACKGROUND The drywell airr lock forms part of the drywell. boundary and i provides a means for personnel access during MODES 2 and 3:

during luw power phase of unit startup. For this purpose,. I one double door drywell air lock has been provided, which  !

maintains drywell isolation during personnel entry and exit. i i

from the drywell. Under the normal unit operation, the drywell air lock. is kept sealed.' ,

The drywell air lock is ' designed to the same standards as l the drywell boundary. Thus, the drywell air lock must i withstand the pressure and temperature transients associated I with the rupture of any primary system line inside the . '

drywell and also the rapid reversal in pressure when the steam in the drywell is condensed by the Emergency Core i '

Cooling System flow following loss of coolant accident flooding of the reactor pressure vessel (RPV). It is also  :

designed to withstand the high temperature associated with the break of a small steam line in the drywell that does'not result in' rapid depressurization of.the RPV. l The air lock is nominally a right circular cylinder, 9 ft 10 inches in diameter, with doors at each end that are interlocked to prevent simultaneous opening. During periods when the drywell is not required to be OPERABLE, the air  !

lock interlock mechanism may be disabled, allowing both  !

doors of the air lock to remain open for extended periods  !

l when frequent drywell entry is necessary. Each air lock  :'

l door has been designed and tested to certify its ability to withstand a pressure in excess of the maximum expected .

ressure following a Design Basis AccideJLIDBA). D I

(The drywell air lock forms part of the drywell pressure  ;

. boundary. Not maintaining air lock OPERABILITY may result f T \, in degradation of the pressure suppression capab.'ity, which I s

1 j

(.to.# $ i ( Js assumed to be functional in the unit safety analyses.j i

63F / The drywell air lock does not need to meet the requirements of 10 CFR-50, Appendix J (Ref.4), since it'is not part of i the primary containment leakage boundary. However, it is 1  :

[ prudent to-specify a leakage rate requirement for the .

l drywell air lock. A seal leakage rate limit-ef a { nfh l (continued) l CLINTON 8 3.6-106 RevisionNo.g .

+

Attechasnt 4 to U-602549 i

- LS-96-001 l Page10gy,,211 Air Lock l B 3.6.5.2 l

[# ._ # ,

i BASES .

t n -

! BACKGROUND and an air lock overall leakage rate limit Of .: : ::fh, :,t  :

(continued) ;r::: r: Le ;:i;, have been established to assure the  ;

integrity of the seals. _

- t

]

8 l APPLICABLE Analytical methods and assumptions involving the drywell are i SAFETY ANALYSES presented in Reference 2. The safety analyses assume that for a high energy line break inside'the drywell, the steam .

is directed to the suppression pool through the horizontal vents where it is condensed. Since the drywell air lock is

]- part of the drywell pressure boundary, its design and

' maintenance are essential to support drywell OPERABILITY,  !

which assures that the safety analyses are met. -

The drywell air lock satisfies Criterion 3 of the NRC Policy i

Statement.

LCO The drywell air lock forms part of the drywell pressure  !

boundary. The air lock safety function assures that steam i

i resulting from a DBA is directed to the suppression pool.

Thus, the air lock's structural integrity is essential to the successful mitigation of such an event.

The air lock is required to be OPERABLE. For the air lock to be considered 0 FRARIF. the air lock interlock mechanism must be OPERABLE ~":t3: it $ 115it:

and both air lock :id:: Fled^pY $:iNB&. )ine un.erm.cB r

i allows only one air lock door of an air lock to be opened at one time. This provision ensures that a gross breach of the i

drywell does not exist when the drywell is required to be i OPERABLE.

)

! Closure of a single door in the air lock is necessary to support drywell OPERABILITY following postulated events.

j Nevertheless, both doors are kept closed when the air lock j is not being used for entry into and exit from the drywell.

4 APPLICABILITY In MODES 1, 2, and 3, a DBA could cause a release of radioactive material to the primary containment. In MODES 4 and 5, the probability and consequences of these events are (continued)

I A f lock Ifakage. is excluded from %is $peciCue . Thd of %e drpelt le a

ou r lock leakeu e. vwit. is e, g i

And is controT e8 as @f+partof cfER ABit ffY of he av'3 MMJ ,

l t I -@ h 5 .1, " De pell . " j L CLINTON B 3.6-107 RevisionNo.g

Attachm:nt 4 to U-602549 LS-96-001 PageIdrNe$$AirLeck B 3.6.5.2 l l

BASES APPLICABILITY reduced due to the pressure and temperature limitations in these MODES. Therefore, the drywell air lock is not (continued) required to be OPERABLE in MODES 4 and 5.

a The ACTIONS are modified by ote[whichallowsentryand exit to perform repairs on he affected air lock component.

ACTIONS If the outer door is inoperable, then it may be easily accessed to repair. If the inner door is inoperable, however, then there is a short time during which the drywell boundary is not intact (during access through the outer .

door). The ability to open the OPERABLE door, even if it l means the drywell boundary is temporarily not intact, is ,

acceptab1p due to the low probability of an event that could l pressurize the drywell during the short time in which the  ;

OPERABLE door is expected to be open. The OPERABLE door must be immediately closed after each entry and exit.

The AC ONS are a ified by a second Note, hich ensures necessary.

appro late rem tal action are taken wh Pur ant to LC 3.0.6, ACT NS are not r quired even if the dr ell is e eeding its ypass leakag limit. Theretore, be e Note is dded to r utre ACTIONS or LCO 3.6.5. j is event, h"akenin A.I. A.2. and A 3 With one drywell air lock door inoperable, the OPERABLE door must be verified closed (Required Action A.1). This ensures that a leak tight drywell barrier is maintained by the use of an OPERABLE air lock door. This action must be completed within I hour. The 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> Compl is consistent with the ACTIONS of LCO 3.6.5. f " Dry ell," which requires that the drywell be restored to PLMAULL s atus within I hour.

In addition, the air lock penetration must be isolated by locking closed the OPERABLE air lock door within the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> Completion Time. The Completion Time is considered reasonable for locking the OPERABLE air lock door, considering that the OPERABLE door is being maintained closed.

(continued)

B 3.6-108 RevisionNo.g CLINTON

, Attcchment 4 to U-602549 LS-96-001 2

Pop 12 DNwe31 Air Lock B 3.6.5.2 BASES ACTIONS B.1. B.2. and 8.3 (continued)_

The Required Actions are modified by two Notes. Note 1 ensures only the Required Actions and associated Completion Times of Condition C are required if both doors in the air lock are inoperable. Note 2 allows entry and exit into the drywell under the control of a dedicated individual stationed at the air lock to ensure that only one door is opened at a time (i.e., the individual performs the function of the interlock). In addition, Note 2 allows an OPERABLE air lock door to remain unlocked, but closed, when the door is under the control of a dedicated individual stationed at the air lock.

With the air lock inoperable for reasons other than those K" described in Condition A or B, Recuired Action C.1 requires to evaluat drywell action to be immedi tely initiatec bypass eakage usi g current air ock test sults. An

< evalu ion is ac ptable, sinc it is over y conservati to Iimme lately de are the dryw inoperab if both do s in an ir lock h e failed a al test or e overall r lock 1 kage is t within li s. In ma instances .g., only ne seal r door has iled), dryw 1 remains 0 RABLE, yet only 1 ur (per LC0 .6.5.1) wou be provide to restor the at lock door OPERABLE s tus prior t requiring plan shutdown, n addition, ven with bo doors fai ng the seal test he overall ywell leakag rate can ill be w hin limit .

<Recuired ction C.2 re ireshatonedoorinthedrywell air lock must be veritted to be closed. This Required Action must be completed within the 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> Completion Time.

This specified time period is consistent with the ACTIONS of i LCO 3.6.5.1, which requires that the drywell be restored to OPERABLE status within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />.

Additionally, the air lock must be restored to OPERABLE status within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. The 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> Completion Time is reasonable for restoring an inoperable air lock to OPERABLE status, considering that at least one door is maintained l closed in the air lock.

J (continued)

CLINTON B 3.6-110 Revision No. M

Attachmnt 4 to U-602549

• LS-96-001, Paga 13 of 22 Drywell Air Lock 8 3.6.5.2 BASES ACTIONS D.1 and 0.2 (continued) If the inoperable drywell air lock cannot be restored to OPERABLE status within the required Completion Time, the plant must be brought to a MODE in which the LCO does not apply. To achieve this status, the plant must be brought to at least MODE 3 within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and to MODE 4 within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />. The allowed Completion Times are reasonable, based on operating experience, to reach the required plant conditions from full power conditions in an orderly manner and without challenging plant systems.

SURVEILLANCE SR 3.6. 2'.1 REQUIREMENTS This SR requires a test be performed to verify seal leakage of the drywell air lock doors at pressures 2: 3.0 psig. A seal leakage rate limit of s 2 scfh has been established to god ensure the integrity of the seals. The Surveillance is on1 l

pf Ip g 3.V ( required to be performed once within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> after each closing. The Frequency of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> is based on operating experience.

SR 3.6.5.

The air lock door interlock is designed to prevent simultaneous opening of both doors in the air lock. Since both the inner and outer doors of the air lock are designed to withstand the maximum expected post accident drywell pressure, closure of either door will support drywell OPERABILITY. Thus, the door interlock feature supports drywell OPERABILITY while the air -lock is being used for personnel transit in and out of the drywell. Periodic testing of this interlock demonstrates that the interlock will function as designed and that simultaneous inner and outer door opening will not inadvertently. occur. Due to the nature of this interlock, and given that the interlock mechanism is only challenged when a drywell air lock door is g ., opened, this test is only required to be performed once 2d everyfJs months. The"Js month Frequency is based on the need to perform this Surveillance under the reduced reactivity conditions that apply during a plant outage and the potential for violating the drywell boundary. Operating h

exper_iangp has___s_hown these comm" -^ually o_

' Surveillance.Wh= F Ffbr& d at the nty cremyenc'e

' meh h Med en_thq r^ fuel % c"c!_e ffhir~e"I'o?eT^1.ne o Frequency a ConcT0'ded 16 be acceptable from a reliability standpoint (continued)

CLINTON B 3.6-111 Revision No. y I

Attechment 4 to U-602549 )

• LS-96-001 j Nga 140NwM1 Air Lock 1 8 3.6.5.2 j BASES SURVEILLANCE SR 3.6.5. I(continued)

REQUIREMENTS The Surveillance is modified by a Note requiring the Surveillance to be performed only upon entry into the drywell.

SR 3.6. 2.4 -

An ove#cdl cair This SR requires a t t to be performed to verify overall air lock leakage of he drywell air lock at pressures loeg t eg y,,ge, month Frequency is based on the need to g g; m ;4 g 2: 3.0 psig.j pihe (perform tnis Surveillance under the conditions that apply '

6 2. scCh ha' during a plant outage and the potential for violating the been eshbtished drywell boundary. Operating experience has shown these yegog %e components usually pass the Surveillance,h perfermed at g th: 20 .;;ath Tr:gency, ;;hich i: b:::d en the refueling g%ej cycle. Therefore, the Frequency was concluded to be <

• Scab. acceptable from a reliability standpoint.

This SR has been modified by a: ."Ote:. The f'r:t-Note (

indic te

that an inoperable air lock door does not J invalidate the previous successful performance of an overall

.' M. air lock leakage test. This is considered reasonable, since either air lock door is capable of providing a fission oduct barrier in the _ event of a_DB_A._

. l. l" f. I. " ,9. f.8. .. .!..wy u_e pf. ,.M.. .,,M. .u. . .,.a. . ,.,_ ,., _. ,, , ,. _ , ,,.,,, th e air lock 1 h be pressurized to 19.7.r .. r.... ..,r............ l Of th: 0;;r:ll cir lock 1 :k:g: t :t. The 10.7 p;id This differential pressure is the assumed peak drywell pressure expected from the accident analysis. Since the drywell Q Q fo pressure rapidly returns to a steady state maximum differential pressure of 3.0 psid (due to suppression pool vent clearing), the lea a e i ed to be measured at B % -101 6 overait air lock.

this pressure.

_ _ _~ _

REFERENCES 1. 10 CFR 50, Appendix J.

2. USAR, Chapters 6 and 15.

B 3.6-112 Revision No. g CLINTON

Attschmint 4 to U-602549 LS-96-001 Y' . " Dr$1 PIN 1$fionValves D conW*h. B 3.6.5.3 l'

i BASES-l BACKGROUND penetration contains a 24-inch (IVQOO2) and a 10-inch (continued) (IVQ005) isolation valve in parallel inside the drywell and a 36-inch (lVQ003) drywell isolation valve outside the drywell in parallel.with a 36-inch containment isolation ,

valve (IVQOO48) which is connected to the containment ventilation system. The system is used to remove trace radioactive airborne products prior to personnel entry. The Drywell Vent and Purge System is seldom used in MODE 1, 2, or 3; therefore, the drywell purge isolation valves are i seldom open during power operation. .

The drywell vent and purge isolation valves fail closed on loss of instrument air or power. The drywell vent and purge exhaust isolation valves are fast closing valves '

(approximately 2 to 4 seconds). These valves are qualified I to close against the differential pressure induced by a loss of coolant accident (LOCA). The drywell vent and purge  :

supply isolation valves are required to be sealed closed in ,

MODES 1, 2, and 3.

l APPLICABLE This LCO is intended to ensure that releases from the core SAFETY ANALYSES do not bypass the suppression pool so that the pressure ,

suppression capability of the drywell is maintained.

Therefore, as part of the drywell boundary, drywell isolation valve OPERABILITY minimizes drywell bypass leakage. Therefore, the safety analysis of any event requiring isolation of the drywell is applicable to this LCO.

The limiting DBA resulting in a release of steam, water, or radioactive material within the drywell is a LOCA. In the analysis for this accident, it is assamed that drywell i isolation valves either are closed or function to close within the required isolation time following event initiatic,n.

The drywell isolation valves and drywell vent and purge isolation valves satisfy Criterion 3 of the NRC Policy Statement.

The drywell . isolation valve safety function is to form a [

LC0 part of the drywell boundary.

i The power operated drywell isolation valves are required to

'l have isolation times within limits. Power operated ,

automatic drywell isolation valves are also required to .!

1 continued)

CLINTON B 3.6-114 Revision No. N

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

\

i Attechasnt 4 to U-602549 i LS-96-001 Pega 16 of 22 Drywell Is'olation . Valves B 3.6.5.3 i

BASES actuate on an automatic isolation signal. Additionally, l LCO l .

drywell vent and purge supply valves are required to be l (continued) J sealed closed. While drywell post-LOCA vacuum relief system valves isolate drywell penetrations, they are excluded from

i. this Specification. Controls on their isolation function are i

' adequately addressed in LCO 3.6.5.6, "Drywell post-LOCA Vacuum Relief System."

I It@W ) j

?

LB34-il5A f  ;

The normally closed isolation valves or blind flanges are considered OPERABLE when, as applicable, manual valves are closed or opened in accordance with applicable  ;

administrative controls, automatic valves are de-activated and secured in their closed position, check valves with flow through the valve secured, or blind flanges are in place. ,

The valvds covered by this LC0 are included (with their l associated stroke time, if applicable, for automatic valves)  ;

~

J in Reference 2.

' For the purpose of meeting this LCO, only one drywell isolation valve or blind flange is required to be OPERABLE .

in each drywell penetration flow path (with the exception of l l l drywell vent and purge valves, and Drywell Post-LOCA Vacuum 4 Relief System valves). This single isolation is acceptable  ;

on the basis that these lines do not communicate directly ,

with the drywell or containment atmospheres. Thus, steam

~

i bypass of the suppression pool is not possible without i

failure of the required isolation valve in conjunction with '

i failures of the piping both inside the drywell and outside the drywell within the containment. Further, failure of multiple flow paths would be required to exceed the

' containment design limitations.

1 i

) -

i i APPLICABILITY In MODES 1, 2, and 3, a DBA could cause a release of '

radioactive material to the primary containment. In MODES 4 and 5, the probability and consequences of these events are l l

reduced due to the pressure and temperature limitations in these MODES. Therefore, the drywell isolation valves are l l  !

not required to be OPERABLE in MODES'4 and 5..

]

-ACTIONS The ACTIONS are modified by Notes. The first Note allows penetration flow paths, except for the drywell vent l l

and purge supply and exhaust penetration flow paths, to be unisolated intermittently under administrative controls. l

! (continued) i CLINTON B 3.6-115 Revision No. M {

I

i Attechnent 4 to U-602549 Ls-96-001 Page 17 of 22 l

l l

INSERT B 3.6-115A  ;

i Orywell isolation valve leakage is excluded from this S)ecification.

the drywell isolation valve leakage rates are aart of tie drywell leakage rate and are controlled as part of OPERABILITY of the drywell  ;

in LC0 3.6.5.1, "Drywell . "

i 9

e 7

h o

l Attachesnt 4 to U-602549'

-LS-96-001, Pags 18 of 22-e Drywell Isolation Valves  :

- B 3.6.5.3 .

+

BASES ACTIONS Due to the size of the drywell vent and purge line penetrations and the fact that they communicate directly l (continued) with the containment atmosphere, bypassing the suppression pool, these flow paths are not allowed to be unisolated under administrative controls. These controls consist of stationing a dedicated individual, who is in continuous communication with the control room, at the controls of the valve. In this way, the penetration can be rapidly isolated when a need for drywell isolation is indicated. i The second Note provides clarification that for the purpose of this LCO separate Condition entry is allowed for each penetration flow path. This is acceptable, since the ,

Required Actions for each Condition provide appropriate compensat'ory actions for each inoperable drywell isolation

~

valve. Complying with the Required Actions may allow for  :

t continued operation, and subsequent inoperable drywell isolation valves are governed by subsequent Condition entry [

and application of associated Required Actions. ,

The third Note requires the OPERABILITY of affected systems to be evaluated when a drywell isolation valve is inoperable. This ensures appropriate remedial actions are taken, if necessary, if the affected system (s) are rendered .

inoperable by an inoperable drywell isolation valve.

b The urth No ensure appropria remedial ctions are/ l ta n when t e drywel bypass le kage limit are exceed 6d.

P suant t LCO 3.0. , these A IONS are t required even en the sociate LC0 is'no met. The fore, Not 3 and 4 ar added t require t e proper a tions to b takenj A.I and A.2 With one or more penetration flow paths with one required drywell isolation valve inoperable, the affected penetration ,

flow path must be isolated. The method of isolation must include the use of at least one isolation barrier that cannot be adversely affected by a single active failure.

Isolation barriers that meet this criterion are a closed and de-activated automatic valve, a closed manual valve, a blind flange, and a check valve with flow through the valve secured. In this condition, the remaining OPERABLE drywell isolation valve is adequate to perform the isolation function for drywell vent and purge system penetrations.

(continued)

CLINTON B 3.6-116 Revision No. F T

Attcchucnt 4 to U-602549

- LS-96-001, Page 19 of 22 Drywell Isolation Valves B 3.6.5.3 BASES ACTIONS A.1 and A.2 (continued)

The associated system piping is adequate to perform the isolation function for other drywell penetrations. However, the overall reliability is reduced because a single failure could result '1n a loss of drywell isolation. The 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> if the ywell des gT p7pT )

A(Completion byp s lea ageTimeANK is of acceptablef 2

sin ACTION Note; 1.lf ft w e exceed ,

J 3 G-II7A, W 4 ill e ure androoriate'conse ativa act ons are i pleme ed. fin addition, the Completion Time is reasonable, considering the time required to isolate the penetration and the relative importance of supporting drywell OPERABILITY during MODES 1, 2, and 3.

For affected penetration flow paths that have been isolated '

in accordance with Required Action A.1, the affected penetrations must be verified to be isolated on a periodic basis. This is necessary to ensure that drywell penetrations that are required to be isolated following an accident, and are no longer capable of being automatically isolated, will be isolated should an event occur. This Required Action does not require any testing or valve manipulation; rather, it involves verification that those devices outside drywell and capable of potentially being mispositioned are in the correct position. Since these devices are inside primary containment, the time period specified as " prior to entering MODE 2 or 3 from MODE 4, if not performed within the previous 92 days," is based on engineering judgment and is considered reasonable in view of the inaccessibility of the devices and other administrative controls that will ensure that misalignment is an unlikely possibility. Also, this Completion Time is consistent with the Completion Time specified for PCIVs in LC0 3.6.1.3,

" Primary Containment Isolation Valves (PCIVs)."

Required Action A.2 is modified by a Note that applies to isolation devices located in high radiation areas and allows them to be verified by use of administrative controls.

Allowing verification by administrative controls is considered acceptable, since access to these areas is typically restricted. Therefore, the probability of misalignment, once they have been verified to be in the-proper position, is low.

(continued)

CLINTON B 3.6-117 Revision No. J d'

Attachment 4 to U-602549-LS-96-001 Page 20 of 22 INSERT B 3.6-117A.

due.to the low probability of the inoperable valve resulting in excessive drywell leakage and the low probability of the limiting event for drywell leakage occurring during this short time.

o 9

M

Attachment'4 to U-602549

+-* LS-96-001 o

D[yde*1blEo1[ionValves B 3.6.5.3 BASES ACTIONS 8.1 (continued)

With one or more drywell vent and purge penetration flow i 4

paths with two drywell isolation valves inoperable, the affected . penetration flow path must be isolated. The method l l

of isolation must include the use of at least one isolation barrier that cannot be adversely affected by a single active failure. Isolation barriers that meet this criterion are a closed and de-activated automatic valve, a closed manual valve, a blind flange, and a check valve with flow through the valve secured. The 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> Completion Time is e ;p. acceptable / s nce if e drywell esign byp ss leaka AM J I M T~ ' of y.18 ft' ere exce ded, ACTIO Note 4 ill ensur B 3.I,-ll8A appropriat conserv ive actio areimpemented.f/he L comp etton Time is reasonable, considering the time. required to isolate the penetration, and the probability of a DBA, which requires the drywell isolation valves to close, occurring during this short time is very low.  ;

Condition B is modified by a Note indicating this Condition is only applicable to drywell vent and purge penetration .

J flow paths. For other penetration flow paths, only one drywell isolation valve is required OPERABLE and, Condition A provides the appropriate Required Actions.

C.1 and C.2 If any Required Action and associated Completion Time cannot be met, the plant must be piscea in a MODE in which the LC0 does not apply. To achie<e this status, the plant must be brought to at least MODE 3 within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and to MODE 4 within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />. The allowed Completion Thes are reasonable, based on operating experience, to reach the required plant conditions from full power conoitions in an 4 orderly manner and without challenging plant systems. ,

SURVEILLANCE SR 3.6.5.3.1 REQUIREMENTS Each 24-inch drywell vent and purge supply isolation valve is required to be verified sealed closed at 31 day  ;

intervals. This Surveillance applies to drywell vent and purge' supply isolation valves since they are not qualified to close under accident conditions. This SR is designed to ensure that a gross breach of drywell is not caused by an inadvertent or spurious drywell vent and purge isolation >

(continued)

CLINTON B 3.6-118 Revision No. J #

Attachment 4'to U-602549  !

,. ...' -LS-96-001  ;

Page 22 4f9.22 i

t i

INSERT B 3.6-118A -

due to the low probability of the inoperable valves resulting in

excessive drywell leakage and the low probability of the limiting

event for drywell leakage occurring during this short time. In 1

~

addition.

l l

! i 1

1 t,

4 1

?

l l

i i

i t

I' i

l

! I 3

d 4

k

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