2CAN049511, Application for Amend to License NPF-6,revising Spec 3.6.1.3 to Allow Entry & Exit of Containment Air Locks to Perform Maint on Air Lock Components

From kanterella
(Redirected from 2CAN049511)
Jump to navigation Jump to search
Application for Amend to License NPF-6,revising Spec 3.6.1.3 to Allow Entry & Exit of Containment Air Locks to Perform Maint on Air Lock Components
ML20082D409
Person / Time
Site: Arkansas Nuclear Entergy icon.png
Issue date: 04/04/1995
From: Yelverton J
ENTERGY OPERATIONS, INC.
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20082D412 List:
References
2CAN049511, 2CAN49511, NUDOCS 9504100095
Download: ML20082D409 (10)
v • d • e


Text

.

4 Entergy Operations, Inc.

1448 S R. 333 9 ENTERGY "T%"S*"

Jerry W. Yelverton vee mese n Operatas thQ April 4,1995 2CAN049511 U. S. Nuclear Regulatory Commission Document Control Desk Mail Station Pl-137 Washington, DC 20555

Subject:

Arkansas Nuclear One- Unit 2 Docket No. 50-368 License No. NPF-6 Technical Specification Change Request Concerning Containment Air Locks Gentlemen:  !

Attached for your review and approval is a proposed Arkansas Nuclear One-Unit 2 (ANO-2)

Technical Specification (TS) amendment revising specification 3.6.1.3 to allow entry and exit of the containment air locks to perform maintenance on air lock components. This ,

amendment would also provide an action statement for an inoperable air lock interlock and l make other changes consistent with NUREG 1432, " Revised Standard Technical i Specifications for Combustion Engineering Plants," Rev 0. 1 The proposed change has been evaluated in accordance with 10CFR50.91(a)(1) using criteria in 10CFR50.92(c) and it has been determined that this change involves no significant hazards considerations. The bases for these determinations are included in the attached submittal.

Entergy Operations requests that the effective date for this change be within 30 days of NRC issuance of the amendment to allow for distribution and procedural revisions necessary to implement this change. Although this request is neither exigent nor emergency, your prompt review is requested.

40005G 9504100095 950404 PUR ADDCK 05000368 $.

P PDR

U. S. NRC

. April 4,1995 2CAN049511 Page 2 Very truly yours,

/-

[d myngm Attachments To the best of my knowledge and belief, the statements contained la this submittal are true.

SUBSCRIBED County and the State ofAND SWORN Arkansas, TO this 4 day of before 24411 me,. 1995.l/ a Notan(Public in and for 0

1Ava 5. 00no muu Notary Public r; u0 JUANA M.TAPP My Commissi6m Expires //-f-AdOQ "Es'feffE" My Commtsson Expres,11 8 -2000

=

. U. S. NRC

, April 4,1995

. 2CAN049511 Page 3 4

cc: Mr. Leonard J. Callan Regional Administrator U. S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011-8064 NRC Senior Resident Inspector Arkansas Nuclear One 1448 S. R. 333 Russellville, AR 72801 Mr. George Kalman NRR Project Manager Region IV/ANO-1 & 2 U. S. Nuclear Regulatory Commission NRR Mail Stop 13-H-3 One White Flint North 11555 Rockville Pike Rockville, MD 20852 Ms. Greta Dicus Arkansas Department ofHealth Division ofRadiation Control and Emergency Management 4815 West Markham Street Little Rock, AR 72205 l

I l

l i

ATTACHMENT IQ 2CAN049511 PROPOSED TECHNICAL SPECIFICATION AND RESPECTIVE SAFETY ANALYSES IN THE MATTER OF AMENDING LICENSENO NPF-6 ENTERGY OPERATIONS, INC.

ARKANSAS NUCLEAR ONE, UNIT TWO DOCKET NO. 50-368 l 1

-l l

i

j
  • Me to

,- 2CAN049511

, Page1of6 DESCRIPTION OF FROPOSED CHANGES e The operability arcap*=ve criteria for an air lock have been removed from the limiting condition for operation section and relocated to the surveillance requirements. 3 t

  • Allowance has been made for one air lock door to be inoperable in each air lock 'mstead of  ;

the current total ofone door.  ;

J l

e Specific allowance has been made to permit air lock entry and exit for maintenance on air i lock cow.pcr. cats.

l e 'An action statement has been added for an inoperable air lock interlock mechanism. '

l

. The action statement requirement to shut down when the next required overall air lock leakage test is to be performed has been removed. I e The surveillance requirements for air lock door seal leakage rate testing have been ,

changed from speci6c acceptance criteria and test methodologies to referencing 10 CFR 50, Appendix J.

e The air lock door seal test minimum pressure has been changed from 54 psig (P.) to 10 psig and the allowable leakage rate has been changed from 175 scem to 0.01 L..

. A statement was added to the bases defining what is considered to be the air lock door.

BACKGROUND The Arkansas Nuclear One-Unit 2 (ANO-2) containment building is equipped with two personnel air locks, one for normal ingress and egress located on the 386' elevation at approximately 135 degrees, the second is the emergency escape hatch located on the 354' elevation at approximately 315 degrees. Each air lock is equipped with two doors, each capable of withholding design pressure (54 psig). The doors are designed to open into the ,

containment building such that internal pressurization will force the door into the seat, enhancing the sealing characteristics of the door. Each door is sealed by concentric elastomeric seal rings and is provided with a 6tting for pressure testing between these seals.

Each door is provided with dogging devices which can be installed as necessary to facilitate leakage rate testing These dogging devices simulate the force that would be exerted on the door seals by containment pressurization during postulated accident conditions. The doors are controlled by a mechamcal interlock which prevents simultaneous opening of both doors.

These air locks are described in the ANO-2 Safety Analysis Report (SAR) Chapter 3.8.1.1.

. Attachment to ,

.2CAN049511 Page 2 of 6' l ANO-2' Technical Specification (TS) 3.6.1.3.a provides actions to be taken should a containment air lock door become inoperable. These actions *nclude locking closed the j operable' door in the affected air lock and verifying that it remains locked closed at least once per 31 days. The current ANO-2 TS contain no provisions for entering and exiting the affected air lock to perform maintenance on inoperable air lock components once a door has i been locked. ' In the event the inner door of an air lock becomes inoperable for any reason, ANO-2 TS requires the outer door be locked, and maintained locked, until the next scheduled  !

overall barrelleskrate test. .

ANO-2 TS 3.6.1.3 currently contains no specific action statement covering an inoperable air lock door interlock. Should an interlock become inoperable with the current specifications,-

_ TS action 3.6.1.3.b would be entered allowing 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> for interlock repair or proceed to hot i standby within six hours and cold shutdown within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.  ;

DISCUSSION OF CHANGE 'l The current ANO-2 TS 3.6.1.3.b limiting condition for operation section contains specific  !

acceptance criteria defining the requirements of an operable air lock. These criteria were l rel-M to the surveillance requirements section as an administrative enhe-awat This l change is consistent with NUREG 1432 " Revised Standard Technical Specifications for Combustion Engineering Plants," Rev 0 (RSTS).

The current ANO-2 TS action a. for 3.6.1.3 specifies actions to be completed should one containment air lock door become inoperable. These actions make no allowance for the fact that ANO-2 has a two air lock containment structure with each door in each air lock rated to withstand full design pressure. Since each door is rated to full design pressure, containment integrity is assured with one operable door in each air lock. The proposed change prescribes actions to be taken with one door inoperable in one or both air locks. This change is consistent with RSTS.

The current ANO-2 TS require that should one containment air lock door become inoperable, the operable door be shut and locked if the inoperable door cannot be restored to an operable condition within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. Should any component other than'the inner door render the air lock inoperable, the inner door can be locked to comply with the specification. .This maintains 1 accessibility to the outer door, and other air lock components,' for repair to allow the restoration of air lock operability. Should the inner air lock door become inoperable, the outer door is required to be locked within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> with no provision for unlocking it for any -

reason. This effectively renders inner door maintenance impossible without a containment  !

entry, at power, through the other air lock. The personnel hatch and emergency escape hatch  ;

air locks are separated by the full diameter of the containment building and two floors in elevation The practice of gaining access to perform maintenance on an inoperable inner door via the other air lock would result in an ure===- y containment entry at power with the associated potential for radiation exposure and heat stress while transiting from one air lock to the other. The time necessary to have the operable outer door open, for ingress and egress a-> y to facilitate air lock repairs, would be two or three minutes per trip. Even

1

^

- Attachment to

. I

< 2CAN049511 l

~

Page 3 of6 )

considering that several trips may be necessary to facilitate the maintenance required to return

~

. an inoperable air lock to an operable status, the combined open time would be much shorter than, and thus bounded by, the current one hour allowable outage time speci6ed in 3.6.1.1, ,

Containment Integrity. The beneSt gained by restoring both doors to an operable status is l preferable to operating for months with a degraded door in an air lock. The ability to unlock )

and open the operable outer door of the affected air lock for maintenance on inoperable air l lock components or an inner door is consistent with the provisions of the RSTS. ,

1 The current ANO-2 Technical Specifications make no reference to the containment air lock interlock mechanism other than to specify a surveillance frequency of once per six months..

An inoperable air lock interlock might make it possible to open both doors in an air lock simultaneously, thereby creating a breach in containment during a mode of operation when I containment integrity is required. To address this condition, an additional action statement is I proposed Should an interlock %== inoperable, closing and locking an air lock door will

. adequately assure that containment integrity will be maintained During ingress and egress via an air lock with an inoperable interlock, a note in the specification requires posting a dedicated ,

I individual at the air lock to control air lock operations. This dedicated individual would adequately duplicate this interlock function. The action times are consistent with those for an inoperable door and with those in the RSTS.

The current ANO-2 Technical Speci6 cations allow for continued power operations with one inoperable containment air lock door until performance of the next overall air lock leakage test at which point the unit would be forced off-line to facilitate repairs. The RSTS allow for indefmite operation with one inoperable air lock door in one or more air locks provided the applicable surveillance requirements continue to be satisfied. Since each air lock door is capable of withstanding full design containment pressure, no significant m ' crease in accident consequences should be realized by continued opastion as long the operable air lock door -

remains closed except as required for ingress and egress per the provisions of this  ;

specification.. i The current ANO-2 TS surveillance requirements 4.6.1.3 stipulate the speci6c leakage rate test methodologies to be used and acceptable values e y to satisfy the operability requirements for a containment air lock. Amending the ANO-2 TS to refer to' 10 CFR 50, Appendix J for the surveillance requirements will preclude the necessity for future amendments based solely on changes to 10 CFR 50, Appendix J. This change is considered administrative in nature based on the removal of duplicatem' formation contained in both the ANO-2 TS and 10 CFR 50, Appendix J. This change is consistent with the RSTS.

The current ANO-2 TS surveillance 4.6.1.3 requires performance of air lock' door seal leakage testing after each door opening, except when the air lock is being used for multiple entries, during modes of operation when containment integrity is required. The door seal test is intended to be a grou test to verify that the door seals were not damaged during the opening and closing cycle (s). This test does not replace the required overall barrel leakage test.

According to the air lock vendor (Trentec), full pressure testing is not required to perform this seal condition verification. The vendor suggests a test pressure of 3 psig as sufficient to meet

,. -+ -

v.=-,-- .. ,y

,_ . - . ___7, __ . __ . _. . _ . . - . ._.

Attachment to_.  !

- 2CAN049511

- Page 4 of 6

. this test requirement. The value of 10' peig was selected for this amendment request to be consistent with RSTS. The current ANO-2-TS require this test to be performed at P.

(assumed peak containment design pressure, 54 psig). Performing the door seal test at a reduced pressure may allow the test to be performed without installing the mechanical dogs.

The current ANO-2 TS surveillance requirements in 4.6.1.3.a specify an acceptable maximum  !

leakage rate of no greater than 175 secm. ' The RSTS uses the fraction 0.01 L. as the' acceptance criteria for this gross check of door seal condition. I, is equal to 0.1% of the net +

free air mass in the containment building at P. and is assumed to leak out of the containment ,

building during a design accident over a 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> period (approximately 162,895 sccm at -  ;

ANO-2). Although changing the acceptable door seal leakage rate from 175 seem to 0.01 I. -

is a relaxation in the sorveillance requirement acceptance criteria, it is acceptable due to the  :

relatively small contributkin to the overall allowable integrated containment leakage rate. This change is consistent with the requirements of RSTS. 1 The current ANO-2 TS contain an exception to 10 CFR 50, Appendix J that allows the -

flexibility not to perform an air lock door seal test after each opening, when the air lock is being used for multiple entries. This exemption is no longer necessary due to a revision to i 10 CFR 50, Appendix J in 1980 which incorporated this flexibility (Reference 45 FR 62789,  ;

9-22-80).

In order to apply the provisions of this specification consistently, a statement was added to the .

bases defining the door as either of the vertical ends of the right circular cylinder that forms the containment air lock. The actions taken in response to a fault that may exist on the moveable portion of the door are equally applicable to the stationary portion of the door. For ,

example, if a test connection located on the stationary door face were to become damaged, it i would not be acceptable to shut and lock the door on the side with the damaged fitting.

Instead, the appropriate action would be to shut and lock the other door to assure containment integrity is maintained.

4 DETERMINATION OF NO SIGNIFICANT HAZARDS CONSIDERATION l l

An evaluation of the proposed change has been performed in accordance with .j 10CFR50.91(a)(1) regarding no significant hazards considerations using the standards in i 10CFR50.92(c). A discussion of these standards as they relate to this amendment request ]

follows-

]

1 Criterlom 1 - Does Not Involve a Significant Incisase in the Probabuity or Consequences of an Accident Previously Evaluateds

, The containment air locks are passive components integral to the containment structure and are not evaluated to be accident initiators, therefore, the proposed amendment does not involve an increase in the probability of an accident previously evaluated.

J . Attachment to l

. 2CAN049511 -

Page 5 of 6 j Each air lock door is rated for and tested to full design pressure of the containment building.

If one door were inoperable in each air lock, the remaining door, since required to remain  !

closed and locked, would provide the r-mary fission product barrier to prevent an t uncontrolled release, therefore the amendment allowance for an inoperable air lock door in -

each air lock does not increase the consequences of any previously evaluated accident -

During a situation where one containment air lock door is inoperable and the operable door is opened, a breech in containment integrity would essentially exist while the operable door- i remains open. The time required for a containment air lock door to be open for ingress or i egress does not exceed two to three minutes. The amendment provision to allow urJoding I and opening an operable air lock door for ingress and egress to facilitate air lock maintenance i

necessary to restore operability does not increase the consequences of any previously evaluated accident since the time necessary for the door to be open is bounded by the existing one hour time allowance for an actual breech of containment integrity (TS 3.6.1.1.)

The containment air lock interlock functions to prevent simultaneous opening of both air lock doors thereby creating a breech in containment integrity. A dedicated individual stationed at the air lock to administratively control door operations, or locking closed an operable door will adequately assure containment integrity. The addition of this technical specification '

action **==t. therefore, does not increat; the consequences of any previous ly evaluated accident.

Performance of the overall air lock leakage test requires opening the outer air lock door for installation of the mechanical dogging devices on the inner door. The current technical  !

specifications make no provisions for this entry and thus would require a plant shutdown if the  !

inner door was inoperable in an air lock. The proposed amendment removes the requirement i to shut down when the barrel leak rate is due. The time required for the containment air lock  ;

doors to be opened for dog installation would be the same a for ingress and egress as  ;

discussed above, therefore this change does not increase the consequences of any previously  ;

evaluated accident. ,

10 CFR 50, Appendix J contains containment leakage testing requirements, including specific requirements for containment building air locks. Changing the TS surveillance requirements to refer to 10 CFR 50, Appendix J for these test requirements will not degrade these tests, <

therefore this change does not increase the consequences of any previously evaluated ,

accident.

The air lock door seal pressure test is performed any time the air lock is used for containment access during modes of operation when containment integrity is required. The door seal test is intended to be a gross test to verify that the door seals were not damaged during the -

opening and closing cycle (s). This test does not replace the required overall barrel leakage

. test. Based on information provided by the air lock vendor, a test pressure of 10 psig is suf5cient to perform this gross seal verification. A change in the allowable leakage rate is requested to remove a specific numerical value from the TS surveillance requirements section and replace it with a fraction of L . This new acceptable leakage rate remains relatively t

--e t-- -

e -- w- w-  % # u- w- weP m -3 4.i 4 $-T -

e---s Y~=f

a 1, a 2,ma- m 2 A ---*a6- - 6 ,

. Attachment to 2CAN049511 .

Page 6 of 6  !

insignificant and is bounded by the overall air lock leakage rate. Based on these facts this - l change in test pressure and associated acceptance criteria does not increase the consequences i of any previously evaluated accident.  !

Therefore, this change does not involve a significant increase in the probability or-consequences of any accident previously evaluated.  :

Criterion 2- Does Not Cmate the Possibuity of a New or Differest Kind of Accident  ;

from any Pnviously Evaluated.  :

Because the proposed changes do not change the design, configuration, or method of l operatica of the plant, they do not create the possibility of a new or different kind of accident  !

from any previously evaluated. .

Criterion 3 - Does Not Involve a Significant Reduction in the Margin of Safety.

The proposed changes to ANO-2 TS involve allowing brief breaches in containment integrity for the purpose of repairing inoperable air lock components or performing suiveillances  ;

required by 10 CFR 50, Appendix J. These cases are adequately bounded by the one hour j allowable outage time afforded by TS 3.6.1.1. )

The addition of a specific action statement addressing an inoperable air lock interlock provides i those actions rw*nnary to assure the maintenance of containment integrity. This is achieved l by locking an operable door in the affected air lock when not in use and stationing a dedicated i individual at the air lock, during periods ofingress and egress, whose sole responsibility is to ,

insure only one air lock door is opened at a time thereby duplicating the function of the j mechanicalinterlock.

l The proposed changes also consist of administrative changes removing an outdated exemption j to 10 CFR 50, Appendix J and removing specific surveillance requirements from the j s#&=*iana, instead referring to the controlling requirements of 10 CFR 50, Appendix J.

This is consistent with the provisions of NUREG 1432 " Revised Standard Technical Specifications for Combustion Fagir-ring Plants," Rev. O.

None of the proposed changes increase the allowable overall air lock leakage rate, nor affect the acceptance criteria of the overall integrated containment leakage rate. All of the changes are bounded by existing analyses for all evaluated accidents and do not create any situations that alter the assumptions used in these analyses. Therefore, this change does not involve a significant reduction in the margin of safety.

Therefore, based upon the reasoning presented above and the previous discussion of the amendment request, Entergy Operations has determined that the requested change does not involve a significant hazards consideration.

l l

l

Retrieved from "https://kanterella.com/w/index.php?title=2CAN049511,_Application_for_Amend_to_License_NPF-6,revising_Spec_3.6.1.3_to_Allow_Entry_%26_Exit_of_Containment_Air_Locks_to_Perform_Maint_on_Air_Lock_Components&oldid=3504458"