ML22240A115

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Changes Related to AP1000 Gts Subsection 3.9.2, Unborated Water Source Flow Paths
ML22240A115
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Issue date: 05/27/2015
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Craig Harbuck NRR/DSS 301-415-3140
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GTST AP1000-A21 -3.9.2, Rev. 1

Advanced Passive 1000 (AP1000)

Generic Technical Specification Traveler (GTST)

Title:

Revision of AP1000 GTS Subsection 3.9.2, Unborated Water Source Flow Paths

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-471-A, Rev. 1: Eliminate use of term CORE ALTERATIONS in ACTIONS and Notes

STS NUREGs Affected:

TSTF-471-A, Rev. 1: NUREG-1 430, -1 431, -1432

NRC Approval Date:

TSTF-471-A Rev. 1: 07-DEC-06

TSTF Classification:

TSTF-471-A, Rev. 1: Technical Change

Date report generated:

Wednesday, May 27, 2015 Page 1 GTST AP1000-A21 -3.9.2, Rev. 1

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:

Not Applicable

RCOL COL Item Number and

Title:

Not Applicable

RCOL PTS Change Number and

Title:

The Vogtle Electric Generating Plant Units 3 and 4 License Amendment Request (VEGP LAR) proposed the following changes to the initial version of the PTS (referred to as the current TS by the VEGP LAR).

These changes include Administrative Changes (A) and Less Restrictive Changes (L) and are discussed in enumerated discussions of change (DOCs). These changes are discussed in Sections VI and VII of this GTST.

DOC A115: Editorial/clarification changes

DOC L03: Deletion of the Required Action A.1 and renumbering subsequent Actions

Date report generated:

Wednesday, May 27, 2015 Page 2 GTST AP1000-A21 -3.9.2, Rev. 1

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(1) applicable to operating reactor designs, but not to the AP1000 design; (2) already incorporated in the GTS; or (3) superseded by another change.

Based on TSTF 471-A, Rev. 1, this GTST removes the term CORE ALTERATIONS and makes corresponding adjustments to the text of the AP1000 LCO and Bases of GTS 3.9.2, Unborated Water Sources Isolation Valves.

The effects of these changes are visible in NUREG -1431, Rev. 4.

Similar to TSTF 471-A, Rev. 1, DOC L03 also removes Required Action A.1 for CORE ALTERATIONS and makes corresponding adjustments to the text in this subsection.

DOC A115 makes several editorial changes that are discussed later in Section VI of this traveler.

Date report generated:

Wednesday, May 27, 2015 Page 3 GTST AP1000-A21 -3.9.2, Rev. 1

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)

APOG Recommended Changes to Improve Bases 3.9.2

Delete the phrase through a system walkdown from SR 3.9.2.1 Surveillance Requirements.

(APOG #490)

Date report generated:

Wednesday, May 27, 2015 Page 4 GTST AP1000-A21 -3.9.2, Rev. 1

V. Applicability

Affected Generic Technical Specifications and Bases:

Section 3.9.2, Unborated Water Source Flow Paths

Changes to the Generic Technical Specifications and Bases:

Remove Required Action A.1 for CORE ALTERATIONS and makes corresponding adjustments to the text in this subsection and Bases. (TSTF-471-A, Rev. 1 and DOC L03)

Revise TS 3.9.2 LCO from Each unborated water source flow path shall be isolated, to One valve in each unborated water source flow path shal l be secured in the closed position. (DOC A115)

Revise TS 3.9.2 Condition A from One or more flow paths not isolated, to One or more unborated water source flow paths with no valve secured in the closed position.(DOC A115)

Revise TS 3.9.2 Required Action A.2 from Initiate actions to isolate flow paths to Initiate actions to secure one valve in the flow path in the closed position. (DOC A115)

Revise SR 3.9.2.1 from Verify each unborated water source flow path is isolated by at least one valve secured in the closed position, to Verify one valve in each unborated water source flow path is secured in the closed position. (DOC A115)

Revise the text in B 3.9.2 LCO paragraph. (DOC A115)

Delete the phrase through a system walkdown from Bases, SR 3.9.2.1 Surveillance Requirements. (APOG #490)

Date report generated:

Wednesday, May 27, 2015 Page 5 GTST AP1000-A21 -3.9.2, Rev. 1

VI. Traveler Information

Description of TSTF changes:

TSTF-471-A, Rev. 1 made the following changes to WOG STS 3.9.2, Rev. 3:

In LCO Subsection 3.9.2:

-Required Action A.1, Suspend CORE ALTERATIONS. and its completion time are removed.

-The underlined word AND is removed.

-The following Item A.2 Initiate actions to isolate flow paths becomes the new item A.1, with its corresponding completion time (Immediately).

-Item A.3 (and its completion time of 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />) is renumbered to A.2.

-The - NOTE - in CONDITION A. is revised from Required Action A.3. to read Required Action A.2.

In the Bases subsection B 3.9.2, the ACTIONS section has three parts: A.1, A.2, and A.3.

-Part A.1 is removed in its entirety.

-Part A.2 becomes part A.1;

-Part A.3 becomes part A.2.

It appears that the second paragraph in the deleted part A.1 under Actions in the Bases has been inadvertently removed. This paragr aph is the only place in the Bases that explains the presence of the Note under Condition A in LCO 3.9.2. This reviewer will restore this paragraph to the Bases before the newly renumbered part A.1. The restored paragraph states:

Condition A has been modified by a Note to require that Required Action A.2 must be completed whenever Condition A is entered.

where Action A.3 is renumbered as A.2.

Rationale for TSTF changes:

TSTF-51-A, Rev. 2 eliminated all uses of the defined term CORE ALTE RATIONS from Applicability statements in the PWR NUREGs and most uses of CORE ALTERATIONS in Required Actions. TSTF-471-A, Rev. 1 eliminates the few remaining instances of the defined term CORE ALTERATIONS from the PWR IRS NUREGs. This GTST continues the removal of the defined term CORE ALTERATIONS from the AP1000 Technical Specifications. This includes the removal of the defined term CORE ALTERATIONS from the list of definitions found in GTS 1.1

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

Administrative Changes (A):

DOC A115:

TS 3.9.2 is revised as follows:

Date report generated:

Wednesday, May 27, 2015 Page 6 GTST AP1000-A21 -3.9.2, Rev. 1

  • TS 3.9.2 LCO statement is revised from Each unborated water source flow path shall be isolated, to One valve in each unborated water source flow path shall be secured in the closed position.
  • TS 3.9.2 Condition A is revised from One or more flow paths not isolated, to One or more unborated water source flow paths with no valve secured in the closed position.
  • TS 3.9.2 Required Action A.2 is revised from Initiate actions to isolate flow paths to Initiate actions to secure one valve in the flow path in the closed position.
  • SR 3.9.2.1 is revised from Verify each unborated water source flow path is isolated by at least one valve secured in the closed position, to Verify one valve in each unborated water source flow path is secured in the closed position.
  • In the Bases subsection B 3.9.2, the ACTIONS section has three parts: A.1, A.2, and A.3.

-Part A.1 is removed in its entirety.

-Part A.2 becomes part A.1;

-Part A.3 becomes part A.2.

These changes are similar to those described before for TSTF-471-A, Rev. 1.

  • In the Bases subsection B 3.9.2, the LCO paragraph is revi sed from:

This LCO requires that flow paths to the RCS from unborated water sources be isolated to prevent unplanned boron dilution during MODE 6 and, thus, avoid a reduction in SHUTDOWN MARGIN.

to:

This LCO requires that at least one valve in each flow paths to the RCS from unborated water sources be secured in the closed position to prevent unplanned boron dilution during MODE 6 and, thus, avoid a reduction in SHUTDOWN MARGIN.

where the changes are underlined.

Less Restrictive Changes (L):

DOC L03:

Similar to TSTF-471-A, Rev. 1, DOC L03 deletes the Required Action A.1 from LCO 3.9.2 and renumbers the subsequent Required Actions.

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

According to DOC A115, the changes described above are made to make the LCO, Action, and SR consistent with each other. The current LCO requires that each unborated water source flow path shall be isolated. One valve secured in the closed position, as is required by current SR 3.9.2.1, ensures this requirement is met. Therefore, to provide clarity between the LCO and SR, the LCO, Action (Condition and Required Action), and SR are all revised to clearly state that one valve per unborated water source flow path is required to be secured in the closed position.

These changes are designated as administrative changes and are acceptable because they do not result in technical changes to the TS.

Date report generated:

Wednesday, May 27, 2015 Page 7 GTST AP1000-A21 -3.9.2, Rev. 1

According to DOC L03 for Condition A for current TS 3.9.1, If one or more unborated water source isolation valves are not secured in the closed position, current actions require that core alterations must be suspended and actions taken to secure the valve in the closed position.

The purpose of this Specification is to prevent a boron dilution incident.

As discussed, core alterations have no effect on a boron dilution incident, either as an initiator or as a mitigator. Suspending core alterations when a valve is not secured does not provide compensation or reduce the probability of the event. Therefore, the action to suspend core alterations provides no safety benefit and is not needed.

Accordingly, the changes made by DOC A115 and DOC L03 are acceptable and are implemented by this GTST in AP1000 STS 3.9.1, Rev. 0.

Description of additional changes proposed by NRC staff/preparer of GTST :

None

Rationale for additional changes proposed by NRC staff/preparer of GTST :

Not applicable

Date report generated:

Wednesday, May 27, 2015 Page 8 GTST AP1000-A21 -3.9.2, Rev. 1

VII. GTST Safety Evaluation

Technical Analysis:

In the WOG and BWOG NUREGs CORE ALTERATION is defined as the movement of any fuel, sources, or reactivity control components, within the reactor vessel with the vessel head removed and fuel in the vessel. Suspension of CORE ALTERATIONS shall not preclude completion of movement of a component to a safe position.

Evaluations performed for TSTF-471-A, Rev. 1 indicate that CORE ALTERATIONS can only occur in Mode 6 when the reactor vessel head is removed. The only accidents considered for Mode 6 for PWR reactors is a fuel handling accident and a boron dilution accident. If all Required Actions that require suspension of CORE ALTERATIONS also require suspension of movement of {recently] irradiated fuel, suspension of CORE ALTERATIONS provides no safety benefit.

The removal of the term CORE ALTERATIONS is usually replaced by or leaves remaining, the term positive reactivity additions. A review of circumstances related to fuel handling accidents and boron dilution accidents concludes that the action to s uspend CORE ALTERATIONS provides no benefit, and is not needed. Hence a finding of no significant hazards consideration is justified.

TSTF-51-A, Rev. 2 eliminated all uses of the defined term CORE ALTERATIONS from Applicability statements in the PWR NUREGs and most uses of CORE ALTERATIONS in Required Actions.

Thus the term CORE ALTERATIONS can be removed from the definitions of Chapter 1 and removed from usage in all other places in the Technical Specifications of NUREG -1431 and AP1000 GTS 1.1.

The above changes are implemented by this GTS in AP1000 STS 3.9.2, Rev. 0 to comply with TSTF-471-A, Rev.1 and to be consistent with the corresponding sections of NUREG -1431, Rev.

4.

Technical discussion for the changes proposed by DOC A115 and DOC L03 are c overed in the previous section VI of this GTST under Rationale for changes in RCOL Std. Dep., RCOL COL Item(s), and RCOL PTS Changes.

References to Previous NRC Safety Evaluation Reports (SERs) :

None

Date report generated:

Wednesday, May 27, 2015 Page 9 GTST AP1000-A21 -3.9.2, Rev. 1

VIII. Review Information

Evaluator Comments:

None

Joseph C. Braun Argonne National Laborator y 630- 252-5574 joebraun@anl.gov

E. Danial Doss Argonne National Laboratory 630-252-5967 doss@anl.gov

Review Information:

Availability for public review and comment on Revision 0 of this traveler approved by NRC staff on 12/12/2012.

APOG Comments (Ref. 7) and Resolutions:

1. (Internal #490) 3.9.2 Bases, Surveillance Requirements: APOG comments that the phrase through a system walkdown should be eliminated from SR 3.9.2.1 as indicated in TSTF-440. TSTF-440 indicated that specifying a system walkdown is inconsistent with the remainder of TS. This change is made as recommended by eliminating the subject phrase.
2. (Internal #3) 3.9.2 Bases,

References:

Insert the FSAR modifier before Chapter 15 in Ref. 1. Throughout the Bases, references to Sections and Chapters of the FSAR do not include the FSAR clarifier. Since these Section and Chapter references are to an external document, it is appropriate to include the FSAR modifier.

NRC Final Approval Date: 0 5/27/2015

NRC

Contact:

Derek Scully U.S. Nuclear Regulatory Commission 301-415-6972 Derek.Scully@nrc.gov

Date report generated:

Wednesday, May 27, 2015 Page 10 GTST AP1000-A21 -3.9.2, Rev. 1

IX. Evaluator Comments for Consideration in Finalizing Technical Specifications and Bases

None

Date report generated:

Wednesday, May 27, 2015 Page 11 GTST AP1000-A21 -3.9.2, Rev. 1

X. References Used in GTST

1. AP1000 DCD, Revision 19, Section 16, Technical Specifications, June 2011 (ML11171A500).
2. Southern Nuclear Operating Company, Vogtle Electric Generating Plant, Units 3 and 4, Technical Specifications Upgrade License Amendment Request, February 24, 2011 (ML12065A057).
3. 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 Enclosure 1 - Amendment No. 13 to COL No. NPF-91 ML13239A256 Enclosure 2 - Amendment No. 13 to COL No. NPF-92 ML13239A284 Enclosure 3 - Revised plant-specific TS pages (Attachment to Amendment No. 13)

ML13239A287 Enclosure 4 - 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 Enclosure 3:

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 Enclosure 3 - Revised plant-specific TS pages (Attachment to Amendment No. 13) (corrected)

4. TSTF-GG 01, Writer's Guide for Plant-Specific Improved Technical Specifications, June 2005.
5. 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).
6. 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 2015, Oc tober 04, 2012 (ML12286A363 and ML12286A360).

Date report generated:

Wednesday, May 27, 2015 Page 12 GTST AP1000-A21 -3.9.2, Rev. 1

7. 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).

Date report generated:

Wednesday, May 27, 2015 Page 13 GTST AP1000-A21 -3.9.2, Rev. 1

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.

Date report generated:

Wednesday, May 27, 2015 Page 14 GTST AP1000-A21 -3.9.2, Rev. 1

Unborated Water Source Flow Paths 3.9.2

3.9 REFUELING OPERATIONS

3.9.2 Unborated Water Source Flow Paths

LCO 3.9.2 EachOne valve in each unborated water source flow path shall be isolated secured in the closed position.

APPLICABILITY: MODE 6

ACTIONS

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

Separate condition entry is allowed for each unborated water source flow path.

CONDITION REQUIRED ACTION COMPLETION TIME

A. ---------- NOTE -----------A.1 Suspend CORE Immediately Required Action A.3 2 ALTERATIONS.

must be completed whenever Condition A is AND entered.

A.21 Initiate actions to isolate Immediately flow paths secure one One or more unborated valve in the flow path in water source flow paths the closed position.

not isolated with no valve secured in the AND closed position.

A.32 Perform SR 3.9.1.1. 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />

SURVEILLANCE REQUIREMENTS

SURVEILLANCE FREQUENCY

SR 3.9.2.1 Verify one valve in each unborated water source flow 31 days path is isolated by at least one valve secured in the closed position.

AP1000 STS 3.9.2-1 Amendment 0Rev. 0 Revision 19 Date report generated:

Wednesday, May 27, 2015 Page 15 GTST AP1000-A21 -3.9.2, Rev. 1

Unborated Water Source Flow Paths B 3.9.2

B 3.9 REFUELING OPERATIONS

B 3.9.2 Unborated Water Source Flow Paths

BASES

BACKGROUND During MODE 6 operation, all flow paths for reactor makeup water sources containing unborated water which are connected to the Reactor Coolant System (RCS) must be closed to prevent an unplanned dilution of the reactor coolant. At least one isolation valve in each flow path must be secured in the closed position.

The Chemical and Volume Control System is capable of supplying borated and unborated water to the RCS through various flow paths.

Since a positive reactivity addition, made by reducing the boron concentration, is inappropriate during MODE 6, isolation of all unborated water sources prevents an unplanned boron dilution event.

APPLICABLE The possibility of an unplanned boron dilution event (Ref. 1) in MODE 6 SAFETY is precluded by adherence to this LCO which requires that potential ANALYSES dilution sources be isolated. Closing the required valves during refueling operations prevents the flow of unborated water to the filled portions of the RCS. The valves are used to isolate unborated water sources.

These valves have the potential to indirectly allow dilution of the RCS boron concentration in MODE 6. By isolating unborated water sources, a safety analysis for an uncontrolled boron dilution accident in accordance with the Standard Review Plan (Ref. 2) is not required in MODE 6.

The RCS boron concentration satisfies Criterion 2 of 10 CFR 50.36(c)(2)(ii).

LCO This LCO requires that at least one valve in each flow paths to the RCS from unborated water sources be secured in the closed position isolated to prevent unplanned boron dilution during MODE 6 and, thus, avoid a reduction in SHUTDOWN MARGIN.

APPLICABILITY In MODE 6, this LCO is applicable to prevent an unplanned boron dilution event by ensuring isolation of all sources of unborated water to the RCS.

AP1000 STS B 3.9.2-1 Amendment 0Rev. 0 Revision 19 Date report generated:

Wednesday, May 27, 2015 Page 16 GTST AP1000-A21 -3.9.2, Rev. 1

Unborated Water Source Flow Paths B 3.9.2

BASES

APPLICABILITY (continued)

In MODES 1 through 5, the requirements of LCO 3.1.9, Chemical and Volume Control System (CVS) Demineralized Water Isolation Valves and Makeup Line Isolation Valves, apply.

ACTIONS The ACTIONS Table has been modified by a Note which allows separate Condition entry for each unborated water source flow path.

A.1

Continuation of CORE ALTERATIONS is contingent upon maintaining the plant in compliance with this LCO. With any valve used to isolate unborated water sources not secured in the closed position, all operations involving CORE ALTERATIONS must be suspended immediately. The Completion Time of Immediately shall not preclude completion of actions to establish a safe condition, including movement of a component to a safe location.

Condition A has been modified by a Note to require that Required Action A.32 must be completed whenever Condition A is entered.

A.21

Preventing unplanned dilution of the reactor coolant boron concentration is dependent on maintaining the unborated water isolation valves secured closed. Securing the valves in the closed position verifies that the valves cannot be inadvertently opened. The Completion Time of Immediately requires an operator to initiate actions to close an open valve and secure the isolation valve in the closed position immediately.

Once actions are initiated, they must be continued until the valves are secured in the closed position.

A.32

Due to the potential of having diluted the boron concentration of the reactor coolant, SR 3.9.1.1 (verification of boron concentration) must be performed whenever Condition A is entered to verify that the required boron concentration exists. The Completion Time of 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> is sufficient to obtain and analyze a reactor coolant sample for boron concentration.

AP1000 STS B 3.9.2-2 Amendment 0Rev. 0 Revision 19 Date report generated:

Wednesday, May 27, 2015 Page 17 GTST AP1000-A21 -3.9.2, Rev. 1

Unborated Water Source Flow Paths B 3.9.2

BASES

SURVEILLANCE SR 3.9.2.1 REQUIREMENTS These valves are to be secured closed to isolate possible dilution flow paths. The likelihood of a significant reduction in the boron concentration during MODE 6 operations is remote due to the large mass of borated water in the refueling cavity and the fact that all unborated water source flow paths are isolated, precluding a dilution. The boron concentration is checked every 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> during MODE 6 under SR 3.9.1.1. This surveillance demonstrates that the valves are closed. through a system walkdown. The 31 day Frequency is based on engineering judgment and is considered reasonable in view of other administrative controls that will verify that the valve opening is an unlikely possibility.

REFERENCES 1. FSAR Chapter 15, Accident Analyses.

2. NUREG-0800, Standard Review Plan, Section 15.4.6, Chemical and Volume Control System Malfunction that Results in a Decrease in Boron Concentration in the RCS.

AP1000 STS B 3.9.2-3 Amendment 0Rev. 0 Revision 19 Date report generated:

Wednesday, May 27, 2015 Page 18 GTST AP1000-A21 -3.9.2, Rev. 1

XII. Applicable STS Subsection After Incorporation of this GTST s Modifications

The entire sub section of the Specifications and the Bases associated with this GTST, following incorporation of the modifications, is presented next.

Date report generated:

Wednesday, May 27, 2015 Page 19 GTST AP1000-A21 -3.9.2, Rev. 1

Unborated Water Source Flow Paths 3.9.2

3.9 REFUELING OPERATIONS

3.9.2 Unborated Water Source Flow Paths

LCO 3.9.2 One valve in each unborated water source flow path shall be secured in the closed position.

APPLICABILITY: MODE 6

ACTIONS

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

Separate condition entry is allowed for each unborated water source flow path.

CONDITION REQUIRED ACTION COMPLETION TIME

A. ---------- NOTE -----------A.1 Initiate actions to secure Immediately Required Action A.2 one valve in the flow path in must be completed the closed position.

whenever Condition A is entered. AND A.2 Perform SR 3.9.1.1. 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> One or more unborated water source flow paths with no valve secured in the closed position.

SURVEILLANCE REQUIREMENTS

SURVEILLANCE FREQUENCY

SR 3.9.2.1 Verify one valve in each unborated water source flow 31 days path is secured in the closed position.

AP1000 STS 3.9.2-1 Rev. 0

Date report generated:

Wednesday, May 27, 2015 Page 20 GTST AP1000-A21 -3.9.2, Rev. 1

Unborated Water Source Flow Paths B 3.9.2

B 3.9 REFUELING OPERATIONS

B 3.9.2 Unborated Water Source Flow Paths

BASES

BACKGROUND During MODE 6 operation, all flow paths for reactor makeup water sources containing unborated water which are connected to the Reactor Coolant System (RCS) must be closed to prevent an unplanned dilution of the reactor coolant. At least one isolation valve in each flow path must be secured in the closed position.

The Chemical and Volume Control System is capable of supplying borated and unborated water to the RCS through various flow paths.

Since a positive reactivity addition, made by reducing the boron concentration, is inappropriate during MODE 6, isolation of all unborated water sources prevents an unplanned boron dilution event.

APPLICABLE The possibility of an unplanned boron dilution event (Ref. 1) in MODE 6 SAFETY is precluded by adherence to this LCO which requires that potential ANALYSES dilution sources be isolated. Closing the required valves during refueling operations prevents the flow of unborated water to the filled portions of the RCS. The valves are used to isolate unborated water sources.

These valves have the potential to indirectly allow dilution of the RCS boron concentration in MODE 6. By isolating unborated water sources, a safety analysis for an uncontrolled boron dilution accident in accordance with the Standard Review Plan (Ref. 2) is not required in MODE 6.

The RCS boron concentration satisfies Criterion 2 of 10 CFR 50.36(c)(2)(ii).

LCO This LCO requires that at least one valve in each flow path to the RCS from unborated water sources be secured in the closed position to prevent unplanned boron dilution during MODE 6 and, thus, avoid a reduction in SHUTDOWN MARGIN.

APPLICABILITY In MODE 6, this LCO is applicable to prevent an unplanned boron dilution event by ensuring isolation of all sources of unborated water to the RCS.

AP1000 STS B 3.9.2-1 Rev. 0

Date report generated:

Wednesday, May 27, 2015 Page 21 GTST AP1000-A21 -3.9.2, Rev. 1

Unborated Water Source Flow Paths B 3.9.2

BASES

APPLICABILITY (continued)

In MODES 1 through 5, the requirements of LCO 3.1.9, Chemical and Volume Control System (CVS) Demineralized Water Isolation Valves and Makeup Line Isolation Valves, apply.

ACTIONS The ACTIONS Table has been modified by a Note which allows separate Condition entry for each unborated water source flow path.

Condition A has been modified by a Note to require that Required Action A.2 must be completed whenever Condition A is entered.

A.1

Preventing unplanned dilution of the reactor coolant boron concentration is dependent on maintaining the unborated water isolation valves secured closed. Securing the valves in the closed position verifies that the valves cannot be inadvertently opened. The Completion Time of Immediately requires an operator to initiate actions to close an open valve and secure the isolation valve in the closed position immediately.

Once actions are initiated, they must be continued until the valves are secured in the closed position.

A.2

Due to the potential of having diluted the boron concentration of the reactor coolant, SR 3.9.1.1 (verification of boron concentration) must be performed whenever Condition A is entered to verify that the required boron concentration exists. The Completion Time of 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> is sufficient to obtain and analyze a reactor coolant sample for boron concentration.

SURVEILLANCE SR 3.9.2.1 REQUIREMENTS These valves are to be secured closed to isolate possible dilution flow paths. The likelihood of a significant reduction in the boron concentration during MODE 6 operations is remote due to the large mass of borated water in the refueling cavity and the fact that all unborated water source flow paths are isolated, precluding a dilution. The boron concentration is checked every 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> during MODE 6 under SR 3.9.1.1. This surveillance demonstrates that the valves are closed.The 31 day Frequency is based on engineering judgment and is considered

AP1000 STS B 3.9.2-2 Rev. 0

Date report generated:

Wednesday, May 27, 2015 Page 22 GTST AP1000-A21 -3.9.2, Rev. 1

Unborated Water Source Flow Paths B 3.9.2

BASES

SURVEILLANCE REQUIREMENTS (continued)

reasonable in view of other administrative controls that will verify that the valve opening is an unlikely possibility.

REFERENCES 1. FSAR Chapter 15, Accident Analyses.

2. NUREG-0800, Standard Review Plan, Section 15.4.6, Chemical and Volume Control System Malfunction that Results in a Decrease in Boron Concentration in the RCS.

AP1000 STS B 3.9.2-3 Rev. 0

Date report generated:

Wednesday, May 27, 2015 Page 23

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