ML22240A082

Changes Related to AP1000 Gts Subsection 3.6.2, Containment Air Locks

ML22240A082
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Issue date:	05/12/2015
From:	NRC/NRR/DSS/STSB
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Craig Harbuck NRR/DSS 301-415-3140
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GTST AP1000-P11-3.6.2, Rev. 1 Date report generated:

Tuesday, May 12, 2015 Page 1 Advanced Passive 1000 (AP1000)

Generic Technical Specification Traveler (GTST)

Title:

Changes Related to LCO 3.6.2, Containment Air Locks I.

Technical Specifications Task Force (TSTF) Travelers, Approved Since Revision 2 of STS NUREG-1431, and Used to Develop this GTST TSTF Number and

Title:

TSTF-52-A, Rev. 3, Implement 10 CFR 50, Appendix J, Option B TSTF-425, Rev. 3, Relocate Surveillance Frequencies to Licensee Control - RITSTF Initiative 5b STS NUREGs Affected:

TSTF-52-A, Rev. 3:

NUREG-1430, 1431, 1432, 1433, 1434 TSTF-425, Rev. 3:

NUREG-1430, 1431, 1432, 1433, 1434 NRC Approval Date:

TSTF-52-A, Rev. 3:

14-Apr-00 TSTF-425, Rev. 3:

06-Jul-09 TSTF Classification:

TSTF-52-A, Rev. 3:

Plant Variation TSTF-425, Rev. 3:

Technical Change

GTST AP1000-P11-3.6.2, Rev. 1 Date report generated:

Tuesday, May 12, 2015 Page 2 II.

Reference Combined License (RCOL) Standard Departures (Std. Dep.), RCOL COL Items, and RCOL Plant-Specific Technical Specifications (PTS) Changes Used to Develop this GTST RCOL Std. Dep. Number and

Title:

None RCOL COL Item Number and

Title:

None RCOL PTS Change Number and

Title:

None

GTST AP1000-P11-3.6.2, Rev. 1 Date report generated:

Tuesday, May 12, 2015 Page 3 III.

Comments on Relations Among TSTFs, RCOL Std. Dep., RCOL COL Items, and RCOL PTS Changes This section discusses the considered changes that are: (1) applicable to operating reactor designs, but not to the AP1000 design; (2) already incorporated in the GTS; or (3) superseded by another change.

TSTF-52-A was partially incorporated into the AP1000 Specification 3.6.2. Other changes that were not previously incorporated and are applicable to the AP1000 Specification 3.6.2 are incorporated.

TSTF-425 is deferred for future consideration.

GTST AP1000-P11-3.6.2, Rev. 1 Date report generated:

Tuesday, May 12, 2015 Page 4 IV.

Additional Changes Proposed as Part of this GTST (modifications proposed by NRC staff and/or clear editorial changes or deviations identified by preparer of GTST)

NRC staff proposed change 1: In the LCO section of the bases the word into is added to the last sentence.

NRC staff proposed change 2: In the Actions section of the bases for Action A.1, A.2, and A.3 the word judgement is changed to judgment.

NRC staff proposed change 3: In the Applicability section of the bases the reference to LCO 3.6.8 is changed to LCO 3.6.7.

APOG Recommended Changes to Improve the Bases Throughout the Bases, references to Sections and Chapters of the FSAR do not include the FSAR modifier. Since these Section and Chapter references are to an external document, it is appropriate to include the acronym FSAR to modify Section and Chapter in references to the FSAR throughout the Bases. (DOC A003)

Revise the Applicable Safety Analyses section of the Bases, by changing the reference to 10 CFR 50, Appendix J to 10 CFR 50, Appendix J, Option B.

Revise the Actions section of the Bases, by changing easily accessed to repair to easily accessed for repair

GTST AP1000-P11-3.6.2, Rev. 1 Date report generated:

Tuesday, May 12, 2015 Page 5 V.

Applicability Affected Generic Technical Specifications and Bases:

Section 3.6.2, Containment Air Locks Changes to the Generic Technical Specifications and Bases:

LCO and Applicable Safety Analyses sections of Bases 3.6.2 are revised to incorporate applicable changes from TSTF-52-A to implement 10 CFR 50 Appendix J, Option B.

LCO section of the Bases the word into is added to the last sentence. (NRC staff proposed change 1)

Actions section of Bases 3.6.2 is revised by changing the word judgement to judgment.

(NRC staff proposed change 2)

Applicability section of Bases 3.6.2 is revised by changing the phrase LCO 3.6.8 to LCO 3.6.7. (NRC staff proposed change 3)

The acronym FSAR is added to modify Section and Chapter in references to the FSAR throughout the Bases. (DOC A003) (APOG Comment)

In the Applicable Safety Analyses section of the Bases, the fourth sentence is revised from 10 CFR 50, Appendix J to 10 CFR 50, Appendix J, Option B. (APOG Comment)

In the Actions section of the Bases, first paragraph, the second sentence is revised from easily accessed to repair to easily accessed for repair (APOG Comment)

GTST AP1000-P11-3.6.2, Rev. 1 Date report generated:

Tuesday, May 12, 2015 Page 6 VI.

Traveler Information Description of TSTF changes:

TSTF-52-A changes to the Bases are to implement 10 CFR 50, Appendix J, Option B. The phrase Design Basis Accident is changed to design basis loss of coolant accident. The word and is replaced with or in the last sentence of the LCO section of the bases.

Rationale for TSTF changes:

TSTF-52-A: Implementation of 10 CFR 50, Appendix J, Option B is already included in Specification 5.5.8, Primary Containment Leakage Rate Testing Program of the AP1000 Technical Specifications. Specifying that the Design Basis Accident is the design basis Loss of Coolant Accident (LOCA) provides clarification. Replacing the word and with or is an editorial change.

Description of changes in RCOL Std. Dep., RCOL COL Item(s), and RCOL PTS Changes:

None Rationale for changes in RCOL Std. Dep., RCOL COL Item(s), and RCOL PTS Changes:

None Description of additional changes proposed by NRC staff/preparer of GTST:

NRC staff proposed change 1: In the LCO section of the bases the word into is added to the last sentence to read as entry into or exit from containment.

NRC staff proposed change 2: In the Actions section of the bases for Action A.1, A.2, and A.3 the word judgement is changed to judgment.

NRC staff proposed change 3: In the Applicability section of the bases the reference to LCO 3.6.8 is changed to LCO 3.6.7.

The acronym FSAR is added to modify Section and Chapter in references to the FSAR throughout the Bases. (DOC A003) (APOG Comment)

Reference to 10 CFR 50, Appendix J in the Applicable Safety Analyses section of the Bases is revised to include 10 CFR 50, Appendix J, Option B. (APOG Comment)

In the Actions section of the Bases, the word to is replaced with for in the sentence easily accessed to repair without interrupting containment integrity. (APOG Comment)

GTST AP1000-P11-3.6.2, Rev. 1 Date report generated:

Tuesday, May 12, 2015 Page 7 Rationale for additional changes proposed by NRC staff/preparer of GTST:

Adding the word into is editorial and aligns the AP1000 Bases for 3.6.2 with NUREG-1431.

In the Actions section of the bases for Action A.1, A.2, and A.3, changing the word judgement to Judgment is editorial.

In the Applicability section of the bases, changing the phrase LCO 3.6.8 to LCO 3.6.7 is a conforming change due to VEGP LAR DOC M13, similar to a change in the bases for TS 3.6.3.

Since Bases references to FSAR Sections and Chapters are to an external document, it is appropriate to include the FSAR modifier.

Revising the reference to 10 CFR 50, Appendix J, Option B improves consistency with STS NUREG-1431, Rev 4.

Replacing the word to with for is an editorial clarification that provides improved clarity, consistency, and operator usability.

GTST AP1000-P11-3.6.2, Rev. 1 Date report generated:

Tuesday, May 12, 2015 Page 8 VII. GTST Safety Evaluation Technical Analysis:

TSTF-52-A: The NRC added Option B, Performance-Based Requirements, to allow licensees to voluntarily replace the prescriptive testing requirements of 10 CFR Part 50, Appendix J, with testing requirements based on both overall performance and the performance of individual components. An NRC Review [ML010930230] found that the TS changes proposed by the licensee are in compliance with the requirements of Option B and are consistent with the guidance of RG 1.163 and TSTF-52, Revision 3.

Other Changes: The remaining changes are editorial, clarifying, grammatical, or otherwise considered administrative. These changes do not affect the technical content, but improve the readability, implementation, and understanding of the requirements, and are therefore acceptable.

Having found that this GTSTs proposed changes to the GTS and Bases are acceptable, the NRC staff concludes that AP1000 STS Subsection 3.6.2 is an acceptable model Specification for the AP1000 standard reactor design.

References to Previous NRC Safety Evaluation Reports (SERs):

Safety Evaluation by the Office of Nuclear Reactor Regulation Related to Amendment No. 194 to Facility Operating License No. DPR-20 Consumer Energy Company Palisades Plant Docket No. 50-255 (ML010930230).

GTST AP1000-P11-3.6.2, Rev. 1 Date report generated:

Tuesday, May 12, 2015 Page 9 VIII. Review Information Evaluator Comments:

None Steve Short Pacific Northwest National Laboratory 509-375-2868 steve.short@pnnl.gov Review Information:

Availability for public review and comment on Revision 0 of this traveler approved by NRC staff on 5/23/2014.

APOG Comments (Ref. 8) and Resolutions:

1.

(Internal #3) Throughout the Bases, references to Sections and Chapters of the FSAR do not include the FSAR modifier. Since these Section and Chapter references are to an external document, it is appropriate (DOC A003) to include the FSAR modifier. This is resolved by adding the FSAR modifier to every FSAR reference in the Bases.

2.

(Internal #13) The NRC approval of TSTF-425, and model safety evaluation provided in the CLIIP for TSTF-425, are generically applicable to any designs Technical Specifications. As such, the replacement of certain Frequencies with a Surveillance Frequency Control Program should be included in the GTST for AP1000 STS NUREG.

However, implementation in the AP1000 STS should not reflect optional (i.e., bracketed) material showing retention of fixed Surveillance Frequencies where relocation to a Surveillance Frequency Control Program is acceptable. Since each represented AP1000 Utility is committed to maintaining standardization, there is no rationale for an AP1000 STS that includes bracketed options.

Consistent with TSTF-425 criteria, replace applicable Surveillance Frequencies with In accordance with the Surveillance Frequency control Program and add that Program as new AP1000 STS Specification 5.5.15.

NRC Staff disagreed with implementing TSTF-425 in the initial version of the STS.

Although the APOG thinks the analysis supporting this traveler is general enough to be applicable to AP1000, staff thinks an AP1000-specific proposal from APOG is needed to identify any GTS SRs that should be excluded. Also, with the adoption of a Surveillance Frequency Control Program (SFCP) in the AP1000 STS, bracketed Frequencies, which provide a choice between the GTS Frequency and the SFCP Frequency, are needed because the NRC will use the AP1000 STS as a reference, and to be consistent with NUREG-1431, Rev. 4. APOG was requested to consider proposing an AP1000 version of TSTF-425 for a subsequent revision of the STS.

3.

(Internal #339) Revise various TS Bases from Appendix J, to Appendix J, Option B for consistency with NUREG-1431 and editorial clarification. This is resolved by making the

GTST AP1000-P11-3.6.2, Rev. 1 Date report generated:

Tuesday, May 12, 2015 Page 10 APOG recommended change to the fourth sentence in the Applicable Safety Analyses section of the Bases.

4.

(Internal #340) Editorial change is recommended in the Actions section of the Bases, first paragraph, second sentence. These non-technical changes provide improved clarity, consistency, and operator usability. This is resolved by making the following APOG recommended change:

if the outer door is inoperable, then it may be easily accessed tofor repair without interrupting containment integrity.

NRC Final Approval Date: 5/12/2015 NRC

Contact:

Hien M. Le United States Nuclear Regulatory Commission 301-415-1511 Hien.Le@nrc.gov

GTST AP1000-P11-3.6.2, Rev. 1 Date report generated:

Tuesday, May 12, 2015 Page 11 IX.

Evaluator Comments for Consideration in Finalizing Technical Specifications and Bases None

GTST AP1000-P11-3.6.2, Rev. 1 Date report generated:

Tuesday, May 12, 2015 Page 12 X.

References Used in GTST

1.

Regulatory Guide 1.163, Performance-Based Containment Leak-Test Program, September 1995, (ML003740058).

2. AP1000 DCD, Revision 19, Section 16, Technical Specifications, June 2011 (ML11171A500).

3.

TSTF-GG-05-01, Writer's Guide for Plant-Specific Improved Technical Specifications, June 2005 (ML070660229).

4.

Southern Nuclear Operating Company, Vogtle Electric Generating Plant, Units 3 and 4, Technical Specifications Upgrade License Amendment Request, February 24, 2011 (ML12065A057).

5.

NRC Safety Evaluation (SE) for Amendment No. 13 to Combined License (COL) No. NPF-91 for Vogtle Electric Generating Plant (VEGP) Unit 3, and Amendment No. 13 to COL No.

NPF-92 for VEGP Unit 4, September 9, 2013, ADAMS Package Accession No. ML13238A337, which contains:

ML13238A355 Cover Letter - Issuance of License Amendment No. 13 for Vogtle Units 3 and 4 (LAR 12-002).

ML13238A359 - Amendment No. 13 to COL No. NPF-91 ML13239A256 - Amendment No. 13 to COL No. NPF-92 ML13239A284 - Revised plant-specific TS pages (Attachment to Amendment No. 13)

ML13239A287 - Safety Evaluation (SE), and Attachment 1 - Acronyms ML13239A288 SE Attachment 2 - Table A - Administrative Changes ML13239A319 SE Attachment 3 - Table M - More Restrictive Changes ML13239A333 SE Attachment 4 - Table R - Relocated Specifications ML13239A331 SE Attachment 5 - Table D - Detail Removed Changes ML13239A316 SE Attachment 6 - Table L - Less Restrictive Changes The following documents were subsequently issued to correct an administrative error in :

ML13277A616 Letter - Correction To The Attachment (Replacement Pages) - Vogtle Electric Generating Plant Units 3 and 4-Issuance of Amendment Re:

Technical Specifications Upgrade (LAR 12-002) (TAC No. RP9402)

ML13277A637 - Revised plant-specific TS pages (Attachment to Amendment No. 13) (corrected)

6.

RAI Letter No. 01 Related to License Amendment Request (LAR)12-002 for the Vogtle Electric Generating Plant Units 3 and 4 Combined Licenses, September 7, 2012 (ML12251A355).

7.

Southern Nuclear Operating Company, Vogtle Electric Generating Plant, Units 3 and 4, Response to Request for Additional Information Letter No. 01 Related to License Amendment Request LAR-12-002, ND-12-2015, October 04, 2012 (ML12286A363 and ML12286A360).

GTST AP1000-P11-3.6.2, Rev. 1 Date report generated:

Tuesday, May 12, 2015 Page 13

8.

APOG-2014-008, APOG (AP1000 Utilities) Comments on AP1000 Standardized Technical Specifications (STS) Generic Technical Specification Travelers (GTSTs), Docket ID NRC-2014-0147, September 22, 2014 (ML14265A493).

GTST AP1000-P11-3.6.2, Rev. 1 Date report generated:

Tuesday, May 12, 2015 Page 14 XI.

MARKUP of the Applicable GTS Subsection for Preparation of the STS NUREG The entire section of the Specifications and the Bases associated with this GTST is presented next.

Changes to the Specifications and Bases are denoted as follows: Deleted portions are marked in strikethrough red font, and inserted portions in bold blue font.

GTST AP1000-P11-3.6.2, Rev. 1 Containment Air Locks 3.6.2 AP1000 STS 3.6.2-1 Amendment 0Rev. 0 Revision 19 Date report generated:

Tuesday, May 12, 2015 Page 15 3.6 CONTAINMENT SYSTEMS 3.6.2 Containment Air Locks LCO 3.6.2 Two containment air locks shall be OPERABLE APPLICABILITY:

MODES 1, 2, 3, and 4.

ACTIONS

---

NOTES----------------------------------------------------------

1.

Entry and exit is permissible to perform repairs on the affected air lock components.

2.

Separate Condition entry is allowed for each air lock.

3.

Enter applicable Conditions and Required Actions of LCO 3.6.1, Containment, when air lock leakage results in exceeding the overall containment leakage rate acceptance criteria.

CONDITION REQUIRED ACTION COMPLETION TIME A. One or more containment air locks with one containment air lock door inoperable.

---

NOTES------------------

1.

Required Actions A.1, A.2, and A.3 are not applicable if both doors in the same air lock are inoperable and Condition C is entered.

2.

Entry and exit is permissible for 7 days under administrative controls if both air locks are inoperable.

A.1 Verify the OPERABLE door is closed in the affected air lock.

AND 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />

GTST AP1000-P11-3.6.2, Rev. 1 Containment Air Locks 3.6.2 AP1000 STS 3.6.2-2 Amendment 0Rev. 0 Revision 19 Date report generated:

Tuesday, May 12, 2015 Page 16 ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME A. (continued)

A.2 Lock the OPERABLE door closed in the affected air lock.

AND 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> A.3

---

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

Air lock doors in high radiation areas may be verified locked closed by administrative means.

Verify the OPERABLE door is locked closed in the affected air lock.

Once per 31 days B. One or more containment air locks with containment air lock interlock mechanism inoperable.

---

NOTES------------------

1.

Required Actions B.1, B.2, and B.3 are not applicable if both doors in the same air lock are inoperable and Condition C is entered.

2.

Entry and exit of containment is permissible under the control of a dedicated individual.

B.1 Verify an OPERABLE door is closed in the affected air lock.

AND 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />

GTST AP1000-P11-3.6.2, Rev. 1 Containment Air Locks 3.6.2 AP1000 STS 3.6.2-3 Amendment 0Rev. 0 Revision 19 Date report generated:

Tuesday, May 12, 2015 Page 17 ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME B. (continued)

B.2 Lock an OPERABLE door closed in the affected air lock.

AND 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> B.3

---

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

Air lock doors in high radiation areas may be verified locked closed by administrative means.

Verify an OPERABLE door is locked closed in the affected air lock.

Once per 31 days C. One or more containment air locks inoperable for reasons other than Condition A or B.

C.1 Initiate action to evaluate overall containment leakage rate per LCO 3.6.1.

AND Immediately C.2 Verify a door is closed in the affected air lock.

AND 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> C.3 Restore air lock to OPERABLE status.

24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> D. Required Action and associated Completion Time not met.

D.1 Be in MODE 3.

AND 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> D.2 Be in MODE 5.

36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />

GTST AP1000-P11-3.6.2, Rev. 1 Containment Air Locks 3.6.2 AP1000 STS 3.6.2-4 Amendment 0Rev. 0 Revision 19 Date report generated:

Tuesday, May 12, 2015 Page 18 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.6.2.1

---

NOTES-----------------------------

1.

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

2.

Results shall be evaluated against acceptance criteria applicable to SR 3.6.1.1.

Perform required air lock leakage rate testing in accordance with the Containment Leakage Rate Testing Program.

In accordance with the Containment Leakage Rate Testing Program SR 3.6.2.2 Verify only one door in the air lock can be opened at a time.

24 months

GTST AP1000-P11-3.6.2, Rev. 1 Containment Air Locks B 3.6.2 AP1000 STS B 3.6.2-1 Amendment 0Rev. 0 Revision 19 Date report generated:

Tuesday, May 12, 2015 Page 19 B 3.6 CONTAINMENT SYSTEMS B 3.6.2 Containment Air Locks BASES BACKGROUND Containment air locks form part of the containment pressure boundary and provide a means for personnel access during all MODES of operation.

Each air lock is nominally a right circular cylinder, 10 feet in diameter, with a door at each end. The doors are interlocked to prevent simultaneous opening. During periods when containment is not required to be OPERABLE, the door interlock mechanism may be disabled, allowing both doors of an air lock to remain open for extended periods when frequent containment entry is necessary. Each air lock door has been designed and tested to certify its ability to withstand a pressure in excess of the maximum expected pressure following a Design Basis Accident (DBA) in containment. As such, closure of a single door supports containment OPERABILITY. Each of the doors contains double gasketed seals and local leakage rate testing capability to ensure pressure integrity. To effect a leak tight seal, the air lock design uses pressure seated doors (i.e., an increase in containment internal pressure results in increased sealing force on each door).

The containment air locks form part of the containment pressure boundary. As such, air lock integrity and leak tightness are essential for maintaining the containment leakage rate within limit in the event of a DBA. Not maintaining air lock integrity or leak tightness may result in a leakage rate in excess of that assumed in the unit safety analyses.

APPLICABLE SAFETY ANALYSES The DBA that results in the largest release of radioactive material within containment is a loss of coolant accident (LOCA) (Ref. 3). In the analyses of DBAs, it is assumed that containment is OPERABLE, such that release of fission products to the environment is controlled by the rate of containment leakage. The containment is designed with an allowable leakage rate of 0.10% of containment air weight of the original content of containment air per day after a DBA (Ref. 2). This leakage rate is defined in 10 CFR 50, Appendix J, Option B (Ref. 1), as La, the maximum allowable containment leakage rate at the calculated peak containment internal pressure Pa following a DBAdesign basis LOCA.

This allowable leakage rate forms the basis for the acceptance criteria imposed on the SRs associated with the air locks.

GTST AP1000-P11-3.6.2, Rev. 1 Containment Air Locks B 3.6.2 AP1000 STS B 3.6.2-2 Amendment 0Rev. 0 Revision 19 Date report generated:

Tuesday, May 12, 2015 Page 20 BASES APPLICABLE SAFETY ANALYSES (continued)

The containment air locks satisfy Criterion 3 of 10 CFR 50.36(c)(2)(ii).

LCO Each containment air lock forms part of the containment pressure boundary. As part of the containment pressure boundary, the air lock safety function is related to control of offsite radiation exposures resulting from a DBA. Thus, each air locks structural integrity and leak tightness are essential to the successful mitigation of such an event.

Each air lock is required to be OPERABLE. For the air lock to be considered OPERABLE, the air lock interlock mechanism must be OPERABLE, the air lock must be in compliance with the Type B air lock leakage test, and both air lock doors must be OPERABLE. The interlock allows only one air lock door of an air lock to be opened at one time.

This provision ensures that a gross breach of containment does not exist when containment is required to be OPERABLE. Closure of a single door in each air lock is necessary to support containment OPERABILITY following postulated events. Nevertheless, both doors are kept closed when the air lock is not being used for normal entry into andor exit from containment.

APPLICABILITY In MODES 1, 2, 3, and 4 a DBA could cause a release of radioactive material to containment. In MODES 5 and 6, the probability and consequences of these events are reduced due to the pressure and temperature limitations of these MODES and large inventory of coolant.

Therefore, containment air locks are not required to be OPERABLE in MODES 5 and 6 to prevent leakage of radioactive material from containment. However, containment closure capability is required within MODES 5 and 6 as specified in LCO 3.6.83.6.7.

ACTIONS The ACTIONS are modified by a Note that allows entry and exit to perform repairs on the affected air lock component. If the outer door is inoperable, then it may be easily accessed tofor repair without interrupting containment integrity. If containment entry is required, it is preferred that the air lock be accessed from inside primary containment by entering through the other OPERABLE air lock. However, if this is not practicable, or if repairs on either door must be performed from the barrel side of the door then it is permissible to enter the air lock through the OPERABLE door, which means there is a short time during which the containment boundary is not intact (during access through the

GTST AP1000-P11-3.6.2, Rev. 1 Containment Air Locks B 3.6.2 AP1000 STS B 3.6.2-3 Amendment 0Rev. 0 Revision 19 Date report generated:

Tuesday, May 12, 2015 Page 21 BASES ACTIONS (continued)

OPERABLE door). The ability to open the OPERABLE door, even if it means the containment boundary is temporarily not intact, is acceptable due to the low probability of an event that could pressurize the containment during the short time in which the OPERABLE door is expected to be open. After each entry and exit, the OPERABLE door must be immediately closed. If ALARA conditions permit, entry and exit should be via an OPERABLE air lock.

A second Note has been added to provide clarification that, for this LCO, separate Condition entry is allowed for each air lock. This is acceptable, since the Required Actions for each Condition provide appropriate compensatory actions for each inoperable air lock. Complying with the Required Actions may allow for continued operation, and a subsequent inoperable air lock is governed by subsequent Condition entry and application of associated Required Actions.

In the event that air lock leakage results in exceeding the overall containment leakage rate, Note 3 directs entry into the applicable Conditions and Required Actions of LCO 3.6.1, Containment.

A.1, A.2, and A.3 With one air lock door in one or more containment air locks inoperable, the OPERABLE door must be verified closed (Required Action A.1) in each affected containment air lock. This ensures a leak tight containment barrier is maintained by the use of an OPERABLE air lock door. This action must be completed within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />. This specified time period is consistent with the ACTIONS of LCO 3.6.1, Containment, which requires containment 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 />.

In addition, the affected 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 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 locking the OPERABLE air lock door, considering the OPERABLE door of the affected air lock is being maintained closed.

Required Action A.3 verifies that an air lock with an inoperable door has been isolated by the use of a locked and closed OPERABLE air lock door. This ensures that an acceptable containment leakage boundary is maintained. The Completion Time of once per 31 days is reasonable based on engineering judgement and is considered adequate in view of

GTST AP1000-P11-3.6.2, Rev. 1 Containment Air Locks B 3.6.2 AP1000 STS B 3.6.2-4 Amendment 0Rev. 0 Revision 19 Date report generated:

Tuesday, May 12, 2015 Page 22 BASES ACTIONS (continued) the low likelihood of a locked door being mispositioned and other administrative controls. Required Action A.3 is modified by a Note that applies to air lock doors located in high radiation areas and allows these doors to be verified to be locked closed by administrative means.

Allowing verification by administrative means is considered acceptable, since access to these areas is typically restricted. Therefore, the probability of misalignment of the door, once it has been verified to be in the proper position, is small.

The Required Actions are modified by two Notes. Note 1 ensures that only the Required Actions and associated Completion Times of Condition C are required if both doors in the airlock are inoperable. With both doors in the same airlock inoperable, an OPERABLE door is not available to be closed. Required Actions C.1 and C.2 are the appropriate remedial actions. The exception of Note 1 does not affect tracking the Completion Time from the initial entry into Condition A; only the requirement to comply with the Required Actions. Note 2 allows use of an airlock for entry and exit for 7 days, under administrative controls if both airlocks have an inoperable door. This 7 day restriction begins when the second air lock is discovered inoperable. Containment entry may be required on a periodic basis to perform Technical Specification (TS) Surveillances and Required Actions, as well as other activities on equipment inside containment that are required by TS or activities on equipment that support TS-required equipment. This Note is not intended to preclude performing other activities (non-TS-related activities) if the containment is entered, using the inoperable airlock, to perform an allowed activity listed above. This allowance is acceptable due to the low probability of an event that could pressurize the containment during the short time in which the OPERABLE door is expected to be open.

B.1, B.2, and B.3 With an air lock door interlock mechanism inoperable in one or more air locks, the Required Actions and associated Completion Times are consistent with Condition A.

The Required Actions have been modified by two Notes. Note 1 ensures that only the Required Actions and associated Completion Times of Condition C are required if both doors in the same airlock are inoperable.

With both doors in the same airlock inoperable, an OPERABLE door is not available to be closed. Required Actions C.1 and C.2 are the

GTST AP1000-P11-3.6.2, Rev. 1 Containment Air Locks B 3.6.2 AP1000 STS B 3.6.2-5 Amendment 0Rev. 0 Revision 19 Date report generated:

Tuesday, May 12, 2015 Page 23 BASES ACTIONS (continued) appropriate remedial actions. Note 2 allows entry into and exit from containment under the control of a dedicated individual stationed at the airlock to ensure that only one door is opened at a time (the individual performs the function of the interlock).

Required Action B.3 is modified by a Note that applies to airlock doors located in high radiation areas that allows these doors to be verified locked closed by administrative means. Allowing verification by administrative means is considered acceptable since access to these areas is typically restricted. Therefore, the probability of misalignment of the door, once it has been verified to be in the proper position is small.

C.1, C.2, and C.3 With one or more air locks inoperable for reasons other than those described in Condition A or B, Required Action C.1 requires action to be initiated immediately to evaluate previous combined leakage rates using current air lock test results. An evaluation is acceptable, since it is overly conservative to immediately declare the containment inoperable if both doors in an air lock have failed a seal test or if the overall air lock leakage is not within limits. In many instances (e.g., only one seal per door has failed), containment remains OPERABLE, yet only 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> (per LCO 3.6.1) would be provided to restore the air lock door to OPERABLE status prior to requiring a plant shutdown. In addition, even with both doors failing the seal test, the overall containment leakage rate can still be within limits.

Required Action C.2 requires that one door in the affected containment air lock must be verified to be closed 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 LCO 3.6.1, which requires that containment 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 affected air lock(s) must be restored to OPERABLE status 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 specified time period is considered reasonable for restoring an inoperable air lock to OPERABLE status, assuming that at least one door is maintained closed in each affected air lock.

GTST AP1000-P11-3.6.2, Rev. 1 Containment Air Locks B 3.6.2 AP1000 STS B 3.6.2-6 Amendment 0Rev. 0 Revision 19 Date report generated:

Tuesday, May 12, 2015 Page 24 BASES ACTIONS (continued)

D.1 and D.2 If the inoperable containment 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 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and to MODE 5 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 REQUIREMENTS SR 3.6.2.1 Maintaining containment air locks OPERABLE requires compliance with the leakage rate test requirements of the Containment Leakage Rate Testing Program. This SR reflects the leakage rate testing requirements with respect to air lock leakage (Type B leakage tests). The acceptance criteria were established during initial air lock and containment OPERABILITY testing. The periodic testing requirements verify that the air lock leakage does not exceed the allowed fraction of the overall containment leakage rate. The Frequency is as required by the Containment Leakage Rate Testing Program.

The SR has been modified by two Notes. Note 1 states that an inoperable air lock door does not invalidate the previous successful performance of the overall air lock leakage test. This is considered reasonable since either air lock door is capable of providing a fission product barrier in the event of a DBA. Note 2 has been added to this SR requiring the results to be evaluated against the acceptance criteria applicable to SR 3.6.1.1. This ensures that air lock leakage is properly accounted for in determining the combined Type B and C containment leakage rate.

SR 3.6.2.2 The air lock door interlock is designed to prevent simultaneous opening of both doors in a single air lock. Since both the inner and outer doors of an air lock are designed to withstand the maximum expected post accident containment pressure, closure of either door will support containment OPERABILITY. Thus, the door interlock feature supports containment OPERABILITY while the air lock is being used for personnel

GTST AP1000-P11-3.6.2, Rev. 1 Containment Air Locks B 3.6.2 AP1000 STS B 3.6.2-7 Amendment 0Rev. 0 Revision 19 Date report generated:

Tuesday, May 12, 2015 Page 25 BASES SURVEILLANCE REQUIREMENTS (continued) transit in and out of the containment. 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 purely mechanical nature of this interlock, and given that the interlock mechanism is not normally challenged when the containment air lock door is used for entry and exit (procedures require strict adherence to single door opening), this test is only required to be performed every 24 months. 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 loss of containment OPERABILITY if the Surveillance were performed with the reactor at power. Operating experience has shown these components usually pass the Surveillance when performed at 24 month Frequency. The 24 month Frequency is based on engineering judgment and is considered adequate given that the interlock is not challenged during the use of the airlock.

REFERENCES

1.

10 CFR 50, Appendix J, Option B Primary Reactor Containment Leakage Testing for Water-Cooled Power Reactors, Performance-Based Requirements.

2.

FSAR Section 6.2, Containment Systems.

3.

FSAR Chapter 15, Accident Analysis.

GTST AP1000-P11-3.6.2, Rev. 1 Date report generated:

Tuesday, May 12, 2015 Page 26 XII. Applicable STS Subsection After Incorporation of this GTSTs Modifications The entire subsection of the Specifications and the Bases associated with this GTST, following incorporation of the modifications, is presented next.

GTST AP1000-P11-3.6.2, Rev. 1 Containment Air Locks 3.6.2 AP1000 STS 3.6.2-1 Rev. 0 Date report generated:

Tuesday, May 12, 2015 Page 27 3.6 CONTAINMENT SYSTEMS 3.6.2 Containment Air Locks LCO 3.6.2 Two containment air locks shall be OPERABLE APPLICABILITY:

MODES 1, 2, 3, and 4.

ACTIONS

---

NOTES----------------------------------------------------------

1.

Entry and exit is permissible to perform repairs on the affected air lock components.

2.

Separate Condition entry is allowed for each air lock.

3.

Enter applicable Conditions and Required Actions of LCO 3.6.1, Containment, when air lock leakage results in exceeding the overall containment leakage rate acceptance criteria.

CONDITION REQUIRED ACTION COMPLETION TIME A. One or more containment air locks with one containment air lock door inoperable.

---

NOTES------------------

1.

Required Actions A.1, A.2, and A.3 are not applicable if both doors in the same air lock are inoperable and Condition C is entered.

2.

Entry and exit is permissible for 7 days under administrative controls if both air locks are inoperable.

A.1 Verify the OPERABLE door is closed in the affected air lock.

AND 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />

GTST AP1000-P11-3.6.2, Rev. 1 Containment Air Locks 3.6.2 AP1000 STS 3.6.2-2 Rev. 0 Date report generated:

Tuesday, May 12, 2015 Page 28 ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME A. (continued)

A.2 Lock the OPERABLE door closed in the affected air lock.

AND 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> A.3

---

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

Air lock doors in high radiation areas may be verified locked closed by administrative means.

Verify the OPERABLE door is locked closed in the affected air lock.

Once per 31 days B. One or more containment air locks with containment air lock interlock mechanism inoperable.

---

NOTES------------------

1.

Required Actions B.1, B.2, and B.3 are not applicable if both doors in the same air lock are inoperable and Condition C is entered.

2.

Entry and exit of containment is permissible under the control of a dedicated individual.

B.1 Verify an OPERABLE door is closed in the affected air lock.

AND 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />

GTST AP1000-P11-3.6.2, Rev. 1 Containment Air Locks 3.6.2 AP1000 STS 3.6.2-3 Rev. 0 Date report generated:

Tuesday, May 12, 2015 Page 29 ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME B. (continued)

B.2 Lock an OPERABLE door closed in the affected air lock.

AND 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> B.3

---

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

Air lock doors in high radiation areas may be verified locked closed by administrative means.

Verify an OPERABLE door is locked closed in the affected air lock.

Once per 31 days C. One or more containment air locks inoperable for reasons other than Condition A or B.

C.1 Initiate action to evaluate overall containment leakage rate per LCO 3.6.1.

AND Immediately C.2 Verify a door is closed in the affected air lock.

AND 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> C.3 Restore air lock to OPERABLE status.

24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> D. Required Action and associated Completion Time not met.

D.1 Be in MODE 3.

AND 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> D.2 Be in MODE 5.

36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />

GTST AP1000-P11-3.6.2, Rev. 1 Containment Air Locks 3.6.2 AP1000 STS 3.6.2-4 Rev. 0 Date report generated:

Tuesday, May 12, 2015 Page 30 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.6.2.1

---

NOTES-----------------------------

1.

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

2.

Results shall be evaluated against acceptance criteria applicable to SR 3.6.1.1.

Perform required air lock leakage rate testing in accordance with the Containment Leakage Rate Testing Program.

In accordance with the Containment Leakage Rate Testing Program SR 3.6.2.2 Verify only one door in the air lock can be opened at a time.

24 months

GTST AP1000-P11-3.6.2, Rev. 1 Containment Air Locks B 3.6.2 AP1000 STS B 3.6.2-1 Rev. 0 Date report generated:

Tuesday, May 12, 2015 Page 31 B 3.6 CONTAINMENT SYSTEMS B 3.6.2 Containment Air Locks BASES BACKGROUND Containment air locks form part of the containment pressure boundary and provide a means for personnel access during all MODES of operation.

Each air lock is nominally a right circular cylinder, 10 feet in diameter, with a door at each end. The doors are interlocked to prevent simultaneous opening. During periods when containment is not required to be OPERABLE, the door interlock mechanism may be disabled, allowing both doors of an air lock to remain open for extended periods when frequent containment entry is necessary. Each air lock door has been designed and tested to certify its ability to withstand a pressure in excess of the maximum expected pressure following a Design Basis Accident (DBA) in containment. As such, closure of a single door supports containment OPERABILITY. Each of the doors contains double gasketed seals and local leakage rate testing capability to ensure pressure integrity. To effect a leak tight seal, the air lock design uses pressure seated doors (i.e., an increase in containment internal pressure results in increased sealing force on each door).

The containment air locks form part of the containment pressure boundary. As such, air lock integrity and leak tightness are essential for maintaining the containment leakage rate within limit in the event of a DBA. Not maintaining air lock integrity or leak tightness may result in a leakage rate in excess of that assumed in the unit safety analyses.

APPLICABLE SAFETY ANALYSES The DBA that results in the largest release of radioactive material within containment is a loss of coolant accident (LOCA) (Ref. 3). In the analyses of DBAs, it is assumed that containment is OPERABLE, such that release of fission products to the environment is controlled by the rate of containment leakage. The containment is designed with an allowable leakage rate of 0.10% of containment air weight of the original content of containment air per day after a DBA (Ref. 2). This leakage rate is defined in 10 CFR 50, Appendix J, Option B (Ref. 1), as La, the maximum allowable containment leakage rate at the calculated peak containment internal pressure Pa following a design basis LOCA. This allowable leakage rate forms the basis for the acceptance criteria imposed on the SRs associated with the air locks.

GTST AP1000-P11-3.6.2, Rev. 1 Containment Air Locks B 3.6.2 AP1000 STS B 3.6.2-2 Rev. 0 Date report generated:

Tuesday, May 12, 2015 Page 32 BASES APPLICABLE SAFETY ANALYSES (continued)

The containment air locks satisfy Criterion 3 of 10 CFR 50.36(c)(2)(ii).

LCO Each containment air lock forms part of the containment pressure boundary. As part of the containment pressure boundary, the air lock safety function is related to control of offsite radiation exposures resulting from a DBA. Thus, each air locks structural integrity and leak tightness are essential to the successful mitigation of such an event.

Each air lock is required to be OPERABLE. For the air lock to be considered OPERABLE, the air lock interlock mechanism must be OPERABLE, the air lock must be in compliance with the Type B air lock leakage test, and both air lock doors must be OPERABLE. The interlock allows only one air lock door of an air lock to be opened at one time.

This provision ensures that a gross breach of containment does not exist when containment is required to be OPERABLE. Closure of a single door in each air lock is necessary to support containment OPERABILITY following postulated events. Nevertheless, both doors are kept closed when the air lock is not being used for normal entry into or exit from containment.

APPLICABILITY In MODES 1, 2, 3, and 4 a DBA could cause a release of radioactive material to containment. In MODES 5 and 6, the probability and consequences of these events are reduced due to the pressure and temperature limitations of these MODES and large inventory of coolant.

Therefore, containment air locks are not required to be OPERABLE in MODES 5 and 6 to prevent leakage of radioactive material from containment. However, containment closure capability is required within MODES 5 and 6 as specified in LCO 3.6.7.

ACTIONS The ACTIONS are modified by a Note that allows entry and exit to perform repairs on the affected air lock component. If the outer door is inoperable, then it may be easily accessed for repair without interrupting containment integrity. If containment entry is required, it is preferred that the air lock be accessed from inside primary containment by entering through the other OPERABLE air lock. However, if this is not practicable, or if repairs on either door must be performed from the barrel side of the door then it is permissible to enter the air lock through the OPERABLE door, which means there is a short time during which the containment boundary is not intact (during access through the OPERABLE door). The

GTST AP1000-P11-3.6.2, Rev. 1 Containment Air Locks B 3.6.2 AP1000 STS B 3.6.2-3 Rev. 0 Date report generated:

Tuesday, May 12, 2015 Page 33 BASES ACTIONS (continued) ability to open the OPERABLE door, even if it means the containment boundary is temporarily not intact, is acceptable due to the low probability of an event that could pressurize the containment during the short time in which the OPERABLE door is expected to be open. After each entry and exit, the OPERABLE door must be immediately closed. If ALARA conditions permit, entry and exit should be via an OPERABLE air lock.

A second Note has been added to provide clarification that, for this LCO, separate Condition entry is allowed for each air lock. This is acceptable, since the Required Actions for each Condition provide appropriate compensatory actions for each inoperable air lock. Complying with the Required Actions may allow for continued operation, and a subsequent inoperable air lock is governed by subsequent Condition entry and application of associated Required Actions.

In the event that air lock leakage results in exceeding the overall containment leakage rate, Note 3 directs entry into the applicable Conditions and Required Actions of LCO 3.6.1, Containment.

A.1, A.2, and A.3 With one air lock door in one or more containment air locks inoperable, the OPERABLE door must be verified closed (Required Action A.1) in each affected containment air lock. This ensures a leak tight containment barrier is maintained by the use of an OPERABLE air lock door. This action must be completed within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />. This specified time period is consistent with the ACTIONS of LCO 3.6.1, Containment, which requires containment 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 />.

In addition, the affected 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 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 locking the OPERABLE air lock door, considering the OPERABLE door of the affected air lock is being maintained closed.

Required Action A.3 verifies that an air lock with an inoperable door has been isolated by the use of a locked and closed OPERABLE air lock door. This ensures that an acceptable containment leakage boundary is maintained. The Completion Time of once per 31 days is reasonable based on engineering judgment and is considered adequate in view of the low likelihood of a locked door being mispositioned and other

GTST AP1000-P11-3.6.2, Rev. 1 Containment Air Locks B 3.6.2 AP1000 STS B 3.6.2-4 Rev. 0 Date report generated:

Tuesday, May 12, 2015 Page 34 BASES ACTIONS (continued) administrative controls. Required Action A.3 is modified by a Note that applies to air lock doors located in high radiation areas and allows these doors to be verified to be locked closed by administrative means.

Allowing verification by administrative means is considered acceptable, since access to these areas is typically restricted. Therefore, the probability of misalignment of the door, once it has been verified to be in the proper position, is small.

The Required Actions are modified by two Notes. Note 1 ensures that only the Required Actions and associated Completion Times of Condition C are required if both doors in the airlock are inoperable. With both doors in the same airlock inoperable, an OPERABLE door is not available to be closed. Required Actions C.1 and C.2 are the appropriate remedial actions. The exception of Note 1 does not affect tracking the Completion Time from the initial entry into Condition A; only the requirement to comply with the Required Actions. Note 2 allows use of an airlock for entry and exit for 7 days, under administrative controls if both airlocks have an inoperable door. This 7 day restriction begins when the second air lock is discovered inoperable. Containment entry may be required on a periodic basis to perform Technical Specification (TS) Surveillances and Required Actions, as well as other activities on equipment inside containment that are required by TS or activities on equipment that support TS-required equipment. This Note is not intended to preclude performing other activities (non-TS-related activities) if the containment is entered, using the inoperable airlock, to perform an allowed activity listed above. This allowance is acceptable due to the low probability of an event that could pressurize the containment during the short time in which the OPERABLE door is expected to be open.

B.1, B.2, and B.3 With an air lock door interlock mechanism inoperable in one or more air locks, the Required Actions and associated Completion Times are consistent with Condition A.

The Required Actions have been modified by two Notes. Note 1 ensures that only the Required Actions and associated Completion Times of Condition C are required if both doors in the same airlock are inoperable.

With both doors in the same airlock inoperable, an OPERABLE door is not available to be closed. Required Actions C.1 and C.2 are the appropriate remedial actions. Note 2 allows entry into and exit from

GTST AP1000-P11-3.6.2, Rev. 1 Containment Air Locks B 3.6.2 AP1000 STS B 3.6.2-5 Rev. 0 Date report generated:

Tuesday, May 12, 2015 Page 35 BASES ACTIONS (continued) containment under the control of a dedicated individual stationed at the airlock to ensure that only one door is opened at a time (the individual performs the function of the interlock).

Required Action B.3 is modified by a Note that applies to airlock doors located in high radiation areas that allows these doors to be verified locked closed by administrative means. Allowing verification by administrative means is considered acceptable since access to these areas is typically restricted. Therefore, the probability of misalignment of the door, once it has been verified to be in the proper position is small.

C.1, C.2, and C.3 With one or more air locks inoperable for reasons other than those described in Condition A or B, Required Action C.1 requires action to be initiated immediately to evaluate previous combined leakage rates using current air lock test results. An evaluation is acceptable, since it is overly conservative to immediately declare the containment inoperable if both doors in an air lock have failed a seal test or if the overall air lock leakage is not within limits. In many instances (e.g., only one seal per door has failed), containment remains OPERABLE, yet only 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> (per LCO 3.6.1) would be provided to restore the air lock door to OPERABLE status prior to requiring a plant shutdown. In addition, even with both doors failing the seal test, the overall containment leakage rate can still be within limits.

Required Action C.2 requires that one door in the affected containment air lock must be verified to be closed 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 LCO 3.6.1, which requires that containment 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 affected air lock(s) must be restored to OPERABLE status 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 specified time period is considered reasonable for restoring an inoperable air lock to OPERABLE status, assuming that at least one door is maintained closed in each affected air lock.

GTST AP1000-P11-3.6.2, Rev. 1 Containment Air Locks B 3.6.2 AP1000 STS B 3.6.2-6 Rev. 0 Date report generated:

Tuesday, May 12, 2015 Page 36 BASES ACTIONS (continued)

D.1 and D.2 If the inoperable containment 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 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and to MODE 5 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 REQUIREMENTS SR 3.6.2.1 Maintaining containment air locks OPERABLE requires compliance with the leakage rate test requirements of the Containment Leakage Rate Testing Program. This SR reflects the leakage rate testing requirements with respect to air lock leakage (Type B leakage tests). The acceptance criteria were established during initial air lock and containment OPERABILITY testing. The periodic testing requirements verify that the air lock leakage does not exceed the allowed fraction of the overall containment leakage rate. The Frequency is as required by the Containment Leakage Rate Testing Program.

The SR has been modified by two Notes. Note 1 states that an inoperable air lock door does not invalidate the previous successful performance of the overall air lock leakage test. This is considered reasonable since either air lock door is capable of providing a fission product barrier in the event of a DBA. Note 2 has been added to this SR requiring the results to be evaluated against the acceptance criteria applicable to SR 3.6.1.1. This ensures that air lock leakage is properly accounted for in determining the combined Type B and C containment leakage rate.

SR 3.6.2.2 The air lock door interlock is designed to prevent simultaneous opening of both doors in a single air lock. Since both the inner and outer doors of an air lock are designed to withstand the maximum expected post accident containment pressure, closure of either door will support containment OPERABILITY. Thus, the door interlock feature supports containment OPERABILITY while the air lock is being used for personnel

GTST AP1000-P11-3.6.2, Rev. 1 Containment Air Locks B 3.6.2 AP1000 STS B 3.6.2-7 Rev. 0 Date report generated:

Tuesday, May 12, 2015 Page 37 BASES SURVEILLANCE REQUIREMENTS (continued) transit in and out of the containment. 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 purely mechanical nature of this interlock, and given that the interlock mechanism is not normally challenged when the containment air lock door is used for entry and exit (procedures require strict adherence to single door opening), this test is only required to be performed every 24 months. 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 loss of containment OPERABILITY if the Surveillance were performed with the reactor at power. Operating experience has shown these components usually pass the Surveillance when performed at 24 month Frequency. The 24 month Frequency is based on engineering judgment and is considered adequate given that the interlock is not challenged during the use of the airlock.

REFERENCES

1.

10 CFR 50, Appendix J, Option B Primary Reactor Containment Leakage Testing for Water-Cooled Power Reactors, Performance-Based Requirements.

2.

FSAR Section 6.2, Containment Systems.

3.

FSAR Chapter 15, Accident Analysis.