ML22240A089
| ML22240A089 | |
| Person / Time | |
|---|---|
| Issue date: | 05/13/2015 |
| From: | NRC/NRR/DSS/STSB |
| To: | |
| Craig Harbuck NRR/DSS 301-415-3140 | |
| Shared Package | |
| ML22240A001 | List:
|
| References | |
| Download: ML22240A089 (26) | |
Text
GTST AP1000-P18-3.6.9, Rev. 1 Advanced Passive 1000 (AP1000)
Generic Technical Specification Traveler (GTST)
Title:
Changes Related to LCO 3.6.9, pH Adjustment 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-425, Rev. 3, Relocate Surveillance Frequencies to Licensee Control - RITSTF Initiative 5b TSTF-440-A, Rev. 0, Eliminate Bases Requirement for Performing a System Walkdown.
TSTF-425, Rev. 3: NUREG-1430, 1431, 1432, 1433, 1434 TSTF-440-A, Rev. 0: NUREG-1430, 1431, 1432 NRC Approval Date:
TSTF-425, Rev. 3: 06-Jul-09 TSTF-440-A, Rev. 0: 11-Oct-02 TSTF Classification:
TSTF-425, Rev. 3: Technical Change TSTF-440-A, Rev. 0: Bases Only Change Date report generated:
Wednesday, May 13, 2015 Page 1
GTST AP1000-P18-3.6.9, 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:
None RCOL COL Item Number and
Title:
None RCOL PTS Change Number and
Title:
VEGP LAR DOC A038: SR 3.6.9.1 and SR 3.6.9.2 clarification revision VEGP LAR DOC A089: TS 3.6.9 Condition A revision VEGP LAR DOC A090: SR 3.6.9.1 revision for consistency with LCO statement VEGP LAR DOC M13: Combined TS 3.6.6 and TS 3.6.7 VEGP LAR DOC D08: TS 3.6.9 chemical formula for TSP removed VEGP LAR DOC L19: TS 3.6.9 TSP unit of measure change Date report generated:
Wednesday, May 13, 2015 Page 2
GTST AP1000-P18-3.6.9, 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(1) applicable to operating reactor designs, but not to the AP1000 design; (2) already incorporated in the GTS; or (3) superseded by another change.
TSTF-425 is deferred for future consideration.
TSTF-440-A revises the Bases to remove specific requirements to perform a system walkdown when verifying that a flow path is isolated or that valves are in the correct position. The change deletes the words through a system walkdown from the Bases for STS (NUREG-1431)
Surveillance Requirement (SR) 3.6.7.1. The AP1000 GTS 3.6.9 does not contain an equivalent SR. This change is not applicable and therefore is not incorporated into AP1000 GTS 3.6.9.
Date report generated:
Wednesday, May 13, 2015 Page 3
GTST AP1000-P18-3.6.9, 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 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 Surveillance Requirements section of the Bases, under heading SR 3.6.8.2 delete the last sentence.
Date report generated:
Wednesday, May 13, 2015 Page 4
GTST AP1000-P18-3.6.9, Rev. 1 V. Applicability Affected Generic Technical Specifications and Bases:
Section 3.6.9, pH Adjustment Changes to the Generic Technical Specifications and Bases:
TS 3.6.9 is renumbered as TS 3.6.8. (DOC M13)
LCO 3.6.9 statement is revised to change the quantity of trisodium phosphate from volume to weight. (DOC L19)
Condition A and Required Action A.1 is revised to change volume to weight and clarify trisodium phosphate is in the pH adjustment baskets. (DOC L19 and DOC A089)
SR 3.6.9.1 is revised to remove the word that. The phrase at least is replaced with and the chemical formula for TSP is removed. (DOC A038, DOC A090, DOC L19, and DOC D08)
SR 3.6.9.2 is revised to remove the word that. (DOC A038)
TS 3.6.9 LCO, Actions, and Surveillance Requirements sections of the bases are revised to change the quantity of trisodium phosphate from volume to weight. (DOC L19)
The acronym FSAR is added to modify Section and Chapter in references to the FSAR throughout the Bases. (DOC A003) (APOG Comment)
The Surveillance Requirements section of the Bases, under heading SR 3.6.8.2 the last sentence is deleted. (APOG Comment)
Date report generated:
Wednesday, May 13, 2015 Page 5
GTST AP1000-P18-3.6.9, Rev. 1 VI. Traveler Information Description of TSTF changes:
None Rationale for TSTF changes:
None Description of changes in RCOL Std. Dep., RCOL COL Item(s), and RCOL PTS Changes:
VEGP LAR DOC A038 deletes the word that from SR 3.6.9.1 and SR 3.6.9.2.
VEGP LAR DOC A089 revises Required Action A.1 to refer to trisodium phosphate as TSP and add the phrase in the pH adjustment baskets. Also, the basis is revised to add the phrase pH adjustment before baskets.
VEGP LAR DOC A090 revises SR 3.6.9.1 by replacing at least with when referring to the required amount of TSP.
VEGP LAR DOC M13 renumbers TS 3.6.9 to TS 3.6.8.
VEGP LAR DOC D08 revises SR 3.6.9.1 by deleting the chemical formula for TSP.
VEGP LAR DOC L19 revises LCO 3.6.9 statement, SR 3.6.9.1 by changing how the required amount of TSP is measured. The required amount of TSP is revised from a volume measurement of 560 ft3 to a weight measurement of 26,460 lbs. Also, corresponding sections in the bases are revised.
Rationale for changes in RCOL Std. Dep., RCOL COL Item(s), and RCOL PTS Changes:
VEGP LAR DOC A038 deletes the word that from SR 3.6.9.1 and SR 3.6.9.2, which is consistent with guidance provided in TSTF-GG-05-01.
VEGP LAR DOC A089 changes to Required Action A.1 and associated basis provides consistency with SR 3.6.9.1 and 3.6.9.2 when referring to the location of TSP.
VEGP LAR DOC A090 change to SR 3.6.9.1 provides consistency with the TS 3.6.9 LCO statement by replacing at least with when referring to the required amount of TSP.
VEGP LAR DOC M13 deletes TS 3.6.7 and subsequent sections are renumbered.
VEGP LAR DOC D08 change to SR 3.6.9.1 by deleting the chemical formula for TSP is a removal of detail from the SR.
VEGP LAR DOC L19 changes to LCO 3.6.9 statement and SR 3.6.9.1 provides a more appropriate parameter to determine quantity of TSP. Since volume will decrease over time (i.e.,
Date report generated:
Wednesday, May 13, 2015 Page 6
GTST AP1000-P18-3.6.9, Rev. 1 density of TSP may increase after installation due to compaction and agglomeration from humidity inside the containment), the more appropriate parameter to establish the LCO requirement against is weight.
Description of additional changes proposed by NRC staff/preparer of GTST:
The acronym FSAR is added to modify Section and Chapter in references to the FSAR throughout the Bases. (DOC A003) (APOG Comment)
The Surveillance Requirements section of the Bases, under heading SR 3.6.8.2 the last sentence is deleted. (APOG Comment)
Rationale for additional changes proposed by NRC staff/preparer of GTST:
Since Bases references to FSAR Sections and Chapters are to an external document, it is appropriate to include the FSAR modifier.
Deleting the last sentence from the Surveillance Requirements section of the Bases, under heading SR 3.6.8.2 is a technical improvement.
Date report generated:
Wednesday, May 13, 2015 Page 7
GTST AP1000-P18-3.6.9, Rev. 1 VII. GTST Safety Evaluation Technical Analysis:
VEGP LAR DOC D08: Deleting the chemical formula for TSP (Na3PO4-12H2O) from SR 3.6.9.1 removes detail from the SR. The removal of the chemical formula for TSP from the SR is acceptable because this type of information is not necessary to be included in the TS to provide adequate protection of public health and safety. The proposed TS retains the necessary requirements to ensure the pH adjustment baskets contain the required TSP, both in the LCO statement and SR 3.6.9.1. Additionally, the Bases present the specific formula for TSP.
VEGP LAR DOC L19: GTS LCO 3.6.9 requires the pH adjustment baskets to contain 560 ft3 of TSP. GTS SR 3.6.9.1 requires verification of this volume (560 ft3) every 24 months. The pH adjustment baskets are part of the Passive Containment Cooling System (PXS), and are provided to adjust the pH of the water in containment following an accident where the containment floods. Following an accident with a large release of radioactivity, the containment pH is automatically adjusted to 7.0 to enhance iodine retention in the containment water. The desired pH value significantly reduces formation of elemental iodine and the total airborne iodine in the containment. The dodecahydrate form of TSP contained in the pH adjustment baskets provides the passive means of pH control for such accidents. The amount of TSP needed to perform this pH adjustment is 26,460 lbs.
The current value is in volume since the weight cannot be readily measured during operation.
However, the conversion from weight to volume is more appropriately controlled in the Surveillance procedure that performs GTS SR 3.6.9.1. Specifically, since volume will decrease over time (i.e., density of TSP may increase after installation due to compaction and agglomeration from humidity inside the containment), the more appropriate parameter to establish the LCO requirement against is weight. The GTS specified volume of 560 ft3 will decrease later in the cycle. The intent of the 560 ft3 (which includes approximately 10%
additional margin) is to establish the pre-compaction and pre-agglomeration volume and not to establish the operability criteria for later in cycle. The TS Bases discusses that the initial loading of TSP includes this 10% volume margin and that the required loading volume prior to compaction and agglomeration is 560 ft3. The Surveillance procedure can adequately control the actual volume necessary to meet the weight requirement, similar to other Surveillances whose measured values must be adjusted to ensure the actual LCO limit is met.
This change is less restrictive since the proposed LCO will allow for a lesser volume over time consistent with expected compaction and agglomeration. However, the accident analysis assumptions concerning the weight of the TSP will still be met by the proposed LCO weight limit of 26,460 lbs.
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 3.6.8 is an acceptable model Specification for the AP1000 standard reactor design.
Date report generated:
Wednesday, May 13, 2015 Page 8
GTST AP1000-P18-3.6.9, Rev. 1 References to Previous NRC Safety Evaluation Reports (SERs):
None Date report generated:
Wednesday, May 13, 2015 Page 9
GTST AP1000-P18-3.6.9, Rev. 1 VIII. Review Information Evaluator Comments:
STS (NUREG-1431) 3.6.7 is equivalent to AP1000 GTS 3.6.9.
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. 7) 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 #6) The GTST sections often repeat VEGP LAR DOCs, which reference existing and current requirements. The inclusion in the GTST of references to existing and current, are not always valid in the context of the GTS. Each occurrence of existing and current should be revised to be clear and specific to GTS, MTS, or VEGP COL TS (or other), as appropriate. This is resolved by making the APOG recommended changes to the GTST.
- 3. (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 Date report generated:
Wednesday, May 13, 2015 Page 10
GTST AP1000-P18-3.6.9, Rev. 1 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.
- 4. (Internal #378) Delete SR 3.6.9.2 Bases last sentence. This sentence, describing compliance to the SRP, is confusing and not necessary in this context. The paragraph begins with Agitation of the test solution is prohibited, which is not related to ensuring compliance with the SRP. As such, the last sentence is deleted. This is resolved by making the APOG recommended change to the Surveillance Requirements section of the Bases.
- 5. (Internal #379) RCOL PTS Change Number and Title for VEGP LAR DOC A089 says it is for TS 3.6.9 Condition B. It affects Condition A not B. This is resolved by making the APOG recommended change to GTST Section II RCOL PTS Change Number and
Title:
NRC Final Approval Date: 5/13/2015 NRC
Contact:
Hien M. Le United States Nuclear Regulatory Commission 301-415-1511 Hien.Le@nrc.gov Date report generated:
Wednesday, May 13, 2015 Page 11
GTST AP1000-P18-3.6.9, Rev. 1 IX. Evaluator Comments for Consideration in Finalizing Technical Specifications and Bases None Date report generated:
Wednesday, May 13, 2015 Page 12
GTST AP1000-P18-3.6.9, 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. 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).
- 4. TSTF-GG-05-01, Writer's Guide for Plant-Specific Improved Technical Specifications, June 2005 (ML070660229).
- 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 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)
- 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).
Date report generated:
Wednesday, May 13, 2015 Page 13
GTST AP1000-P18-3.6.9, 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 13, 2015 Page 14
GTST AP1000-P18-3.6.9, 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 13, 2015 Page 15
GTST AP1000-P18-3.6.9, Rev. 1 pH Adjustment 3.6.98 3.6 CONTAINMENT SYSTEMS 3.6.98 pH Adjustment LCO 3.6.98 The pH adjustment baskets shall contain 560 ft326,460 lbs of trisodium phosphate (TSP).
APPLICABILITY: MODES 1, 2, 3, and 4.
ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. The volumeweight of A.1 Restore volumeweight of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> trisodium phosphateTSP trisodium phosphateTSP in in the pH adjustment the pH adjustment baskets not within limit. baskets to within limit.
B. Required Action and B.1 Be in MODE 3. 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> associated Completion Time not met. AND B.2 Be in MODE 5. 84 hours9.722222e-4 days <br />0.0233 hours <br />1.388889e-4 weeks <br />3.1962e-5 months <br /> SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.6.98.1 Verify that the pH adjustment baskets contain at least 24 months 560 ft3 26,460 lbs of TSP (Na3PO4-12 H2O).
SR 3.6.98.2 Verify that a sample from the pH adjustment baskets 24 months provides adequate pH adjustment of the post-accident water.
AP1000 STS 3.6.98-1 Amendment 0Rev. 0 Revision 19 Date report generated:
Wednesday, May 13, 2015 Page 16
GTST AP1000-P18-3.6.9, Rev. 1 pH Adjustment B 3.6.98 B 3.6 CONTAINMENT SYSTEMS B 3.6.98 pH Adjustment BASES BACKGROUND The Passive Core Cooling System (PXS) includes four pH adjustment baskets which provide adjustment of the pH of the water in the containment following an accident where the containment floods.
Following an accident with a large release of radioactivity, the containment pH is automatically adjusted to greater than or equal to 7.0, to enhance iodine retention in the containment water. Chemical addition is necessary to counter the affects of the boric acid contained in the safety injection supplies and acids produced in the post-LOCA environment (nitric acid from the irradiation of water and air and hydrochloric acid from irradiation and pyrolysis of electric cable insulation). The desired pH values significantly reduce formation of elemental iodine in the containment water, which reduces the production of organic iodine and the total airborne iodine in the containment. This pH adjustment is also provided to prevent stress corrosion cracking of safety related containment components during long-term cooling.
Dodecahydrate trisodium phosphate (TSP) contained in baskets provides a passive means of pH control for such accidents. The baskets are made of stainless steel with a mesh front that readily permits contact with water. These baskets are located inside containment at an elevation that is below the minimum floodup level. The baskets are placed at least a foot above the floor to reduce the chance that water spills will dissolve the TSP. Natural recirculation of water inside the containment, following a LOCA, is driven by the core decay heat and provides mixing to achieve a uniform pH. The dodecahydrate form of TSP (Na3PO4*12H2O) is initially loaded into the baskets because it is hydrated and will undergo less physical and chemical change than would anhydrous TSP as a result of the humidity inside containment. (Refs. 1 and 2)
APPLICABLE In the event of a Design Basis Accident (DBA), iodine may be released SAFETY from the fuel to containment. To limit this iodine release from ANALYSES containment, the pH of the water in the containment sump is adjusted by the addition of TSP. Adjusting the sump water to neutral or alkaline pH (pH 7.0) will augment the retention of the iodine, and thus reduce the iodine available to leak to the environment.
AP1000 STS B 3.6.98-1 Amendment 0Rev. 0 Revision 19 Date report generated:
Wednesday, May 13, 2015 Page 17
GTST AP1000-P18-3.6.9, Rev. 1 pH Adjustment B 3.6.98 BASES APPLICABLE SAFETY ANALYSES (continued) pH adjustment satisfies Criterion 3 of 10 CFR 50.36(c)(2)(ii).
LCO The requirement to maintain the pH adjustment baskets with 560 ft3 26,460 lbs of TSP assures that for DBA releases of iodine into containment, the pH of the containment sump will be adjusted to enhance the retention of the iodine.
A required volume is specified instead of mass because it is not feasible to weigh the TSP in the containment. The minimum required volume is based on the manufactured density of TSP. This is conservative because the density of TSP may increase after installation due to compaction.
APPLICABILITY In MODES 1, 2, 3, and 4 a DBA could cause release of radioactive iodine to containment requiring pH adjustment. The pH adjustment baskets assist in reducing the airborne iodine fission product inventory available for release to the environment.
In MODES 5 and 6, the probability and consequences of these events are reduced due to the pressure and temperature limitations of these MODES. Thus, pH adjustment is not required to be OPERABLE in MODES 5 and 6.
ACTIONS A.1 If the TSP volumeweight in the pH adjustment baskets is not within limits, the iodine retention may be less than that assumed in the accident analysis for the limiting DBA. Due to the very low probability that the volumeweight of TSP may change, the variations are expected to be minor such that the required capability is substantially available. The 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> Completion Time for restoration to within limits is consistent with times applied to minor degradations of ECCS parameters.
AP1000 STS B 3.6.98-2 Amendment 0Rev. 0 Revision 19 Date report generated:
Wednesday, May 13, 2015 Page 18
GTST AP1000-P18-3.6.9, Rev. 1 pH Adjustment B 3.6.98 BASES ACTIONS (continued)
B.1 and B.2 If the Required Actions and associated Completion Times are not met, 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 84 hours9.722222e-4 days <br />0.0233 hours <br />1.388889e-4 weeks <br />3.1962e-5 months <br />. The allowed Completion Times are reasonable, based on operating experience, to reach the required plant conditions from full power conditions in an orderly manner and without challenging plant systems.
SURVEILLANCE SR 3.6.98.1 REQUIREMENTS The minimum amount of TSP is 26,460 lbs560 ft3. A volume is specified since it is not feasible to weigh the TSP contained in the pH adjustment baskets. This volumeweight is based on providing sufficient TSP to buffer the post accident containment water to a minimum pH of 7.0.
Additionally, the TSP volumeweight is based on treating the maximum volume of post accident water (908,000 gallons) containing the maximum amount of boron (2990 ppm) as well as other sources of acid. The minimum required mass of TSP is 26,460 pounds at an assumed assay of 100%.
While a weight is specified, the normal manner to confirm the weight limit is met is by measuring the volume of the TSP contained in the pH adjustment baskets. The minimum requiredmeasured volume of TSP is based on this minimum required mass of TSP (26,460 lbs), theand normally assumes the minimum density of TSP plus margin (about 10%) to account for degradation (agglomeration) of TSP during plant operation. The minimum TSP density is based on the manufactured density (54 lbm/ft3), since the density may increase and the volume decrease, during plant operation, due to agglomeration from humidity inside the containment. This results in a TSP volume of TSP 560 ft3 at the initial loading (i.e., prior to compaction and agglomeration).The minimum required TSP volume also has about 10%
margin to account for degradation of TSP during plant operation.
The periodic verification is required every 24 months, since access to the TSP baskets is only feasible during outages, and normal fuel cycles are scheduled for 24 months. Operating experience has shown this Surveillance Frequency acceptable due to the margin in the volume of TSP placed in the containment building.
AP1000 STS B 3.6.98-3 Amendment 0Rev. 0 Revision 19 Date report generated:
Wednesday, May 13, 2015 Page 19
GTST AP1000-P18-3.6.9, Rev. 1 pH Adjustment B 3.6.98 BASES SURVEILLANCE REQUIREMENTS (continued)
SR 3.6.98.2 Testing must be performed to ensure the solubility and buffering ability of the TSP after exposure to the containment environment. A representative sample of 2.39 grams of TSP from one of the baskets in containment is submerged in 1 liter of water at a boron concentration of 2990 ppm and at the standard temperature of 25 +/- 5°C. Without agitation, the solution pH should be raised to 7.0 within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.
The minimum required amount of TSP is sufficient to buffer the maximum amount of boron 2990 ppm, the maximum amount of other acids, and the maximum amount of water 908,000 gallons that can exist in the containment following an accident and achieve a minimum pH of 7.0.
Agitation of the test solution is prohibited, since an adequate standard for the agitation intensity cannot be specified. The test time of 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> is necessary to allow time for the dissolved TSP to naturally diffuse through the sample solution. In the post LOCA sump area, rapid mixing would occur due to liquid flow, significantly decreasing the actual amount of time before the required pH is achieved. This would ensure compliance with the Standard Review Plan requirement of a pH 7.0 by the onset of recirculation after a LOCA.
REFERENCES 1. FSAR Section 6.3.2.1.4, Containment pH Control.
- 2. FSAR Section 6.3.2.2.4, pH Adjustment Baskets.
AP1000 STS B 3.6.98-4 Amendment 0Rev. 0 Revision 19 Date report generated:
Wednesday, May 13, 2015 Page 20
GTST AP1000-P18-3.6.9, Rev. 1 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.
Date report generated:
Wednesday, May 13, 2015 Page 21
GTST AP1000-P18-3.6.9, Rev. 1 pH Adjustment 3.6.8 3.6 CONTAINMENT SYSTEMS 3.6.8 pH Adjustment LCO 3.6.8 The pH adjustment baskets shall contain 26,460 lbs of trisodium phosphate (TSP).
APPLICABILITY: MODES 1, 2, 3, and 4.
ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. The weight of TSP in the A.1 Restore weight of TSP in 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> pH adjustment baskets the pH adjustment baskets not within limit. to within limit.
B. Required Action and B.1 Be in MODE 3. 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> associated Completion Time not met. AND B.2 Be in MODE 5. 84 hours9.722222e-4 days <br />0.0233 hours <br />1.388889e-4 weeks <br />3.1962e-5 months <br /> SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.6.8.1 Verify the pH adjustment baskets contain 26,460 lbs 24 months of TSP.
SR 3.6.8.2 Verify a sample from the pH adjustment baskets 24 months provides adequate pH adjustment of the post-accident water.
AP1000 STS 3.6.8-1 Rev. 0 Date report generated:
Wednesday, May 13, 2015 Page 22
GTST AP1000-P18-3.6.9, Rev. 1 pH Adjustment B 3.6.8 B 3.6 CONTAINMENT SYSTEMS B 3.6.8 pH Adjustment BASES BACKGROUND The Passive Core Cooling System (PXS) includes four pH adjustment baskets which provide adjustment of the pH of the water in the containment following an accident where the containment floods.
Following an accident with a large release of radioactivity, the containment pH is automatically adjusted to greater than or equal to 7.0, to enhance iodine retention in the containment water. Chemical addition is necessary to counter the affects of the boric acid contained in the safety injection supplies and acids produced in the post-LOCA environment (nitric acid from the irradiation of water and air and hydrochloric acid from irradiation and pyrolysis of electric cable insulation). The desired pH values significantly reduce formation of elemental iodine in the containment water, which reduces the production of organic iodine and the total airborne iodine in the containment. This pH adjustment is also provided to prevent stress corrosion cracking of safety related containment components during long-term cooling.
Dodecahydrate trisodium phosphate (TSP) contained in baskets provides a passive means of pH control for such accidents. The baskets are made of stainless steel with a mesh front that readily permits contact with water. These baskets are located inside containment at an elevation that is below the minimum floodup level. The baskets are placed at least a foot above the floor to reduce the chance that water spills will dissolve the TSP. Natural recirculation of water inside the containment, following a LOCA, is driven by the core decay heat and provides mixing to achieve a uniform pH. The dodecahydrate form of TSP (Na3PO4*12H2O) is initially loaded into the baskets because it is hydrated and will undergo less physical and chemical change than would anhydrous TSP as a result of the humidity inside containment. (Refs. 1 and 2)
APPLICABLE In the event of a Design Basis Accident (DBA), iodine may be released SAFETY from the fuel to containment. To limit this iodine release from ANALYSES containment, the pH of the water in the containment sump is adjusted by the addition of TSP. Adjusting the sump water to neutral or alkaline pH (pH 7.0) will augment the retention of the iodine, and thus reduce the iodine available to leak to the environment.
AP1000 STS B 3.6.8-1 Rev. 0 Date report generated:
Wednesday, May 13, 2015 Page 23
GTST AP1000-P18-3.6.9, Rev. 1 pH Adjustment B 3.6.8 BASES APPLICABLE SAFETY ANALYSES (continued) pH adjustment satisfies Criterion 3 of 10 CFR 50.36(c)(2)(ii).
LCO The requirement to maintain the pH adjustment baskets with 26,460 lbs of TSP assures that for DBA releases of iodine into containment, the pH of the containment sump will be adjusted to enhance the retention of the iodine.
APPLICABILITY In MODES 1, 2, 3, and 4 a DBA could cause release of radioactive iodine to containment requiring pH adjustment. The pH adjustment baskets assist in reducing the airborne iodine fission product inventory available for release to the environment.
In MODES 5 and 6, the probability and consequences of these events are reduced due to the pressure and temperature limitations of these MODES. Thus, pH adjustment is not required to be OPERABLE in MODES 5 and 6.
ACTIONS A.1 If the TSP weight in the pH adjustment baskets is not within limits, the iodine retention may be less than that assumed in the accident analysis for the limiting DBA. Due to the very low probability that the weight of TSP may change, the variations are expected to be minor such that the required capability is substantially available. The 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> Completion Time for restoration to within limits is consistent with times applied to minor degradations of ECCS parameters.
B.1 and B.2 If the Required Actions and associated Completion Times are not met, 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 84 hours9.722222e-4 days <br />0.0233 hours <br />1.388889e-4 weeks <br />3.1962e-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.
AP1000 STS B 3.6.8-2 Rev. 0 Date report generated:
Wednesday, May 13, 2015 Page 24
GTST AP1000-P18-3.6.9, Rev. 1 pH Adjustment B 3.6.8 BASES SURVEILLANCE SR 3.6.8.1 REQUIREMENTS The minimum amount of TSP is 26,460 lbs. This weight is based on providing sufficient TSP to buffer the post accident containment water to a minimum pH of 7.0. Additionally, the TSP weight is based on treating the maximum volume of post accident water (908,000 gallons) containing the maximum amount of boron (2990 ppm) as well as other sources of acid. The minimum required mass of TSP is 26,460 pounds at an assumed assay of 100%.
While a weight is specified, the normal manner to confirm the weight limit is met is by measuring the volume of the TSP contained in the pH adjustment baskets. The measured volume of TSP is based on this minimum required mass of TSP (26,460 lbs), and normally assumes the minimum density of TSP plus margin (about 10%) to account for degradation (agglomeration) of TSP during plant operation. The minimum TSP density is based on the manufactured density (54 lbm/ft3),
since the density may increase and the volume decrease, during plant operation, due to agglomeration from humidity inside the containment.
This results in a TSP volume of TSP 560 ft3 at the initial loading (i.e., prior to compaction and agglomeration).
The periodic verification is required every 24 months, since access to the TSP baskets is only feasible during outages, and normal fuel cycles are scheduled for 24 months. Operating experience has shown this Surveillance Frequency acceptable due to the margin in the volume of TSP placed in the containment building.
SR 3.6.8.2 Testing must be performed to ensure the solubility and buffering ability of the TSP after exposure to the containment environment. A representative sample of 2.39 grams of TSP from one of the baskets in containment is submerged in 1 liter of water at a boron concentration of 2990 ppm and at the standard temperature of 25 +/- 5°C. Without agitation, the solution pH should be raised to 7.0 within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.
The minimum required amount of TSP is sufficient to buffer the maximum amount of boron 2990 ppm, the maximum amount of other acids, and the maximum amount of water 908,000 gallons that can exist in the containment following an accident and achieve a minimum pH of 7.0.
AP1000 STS B 3.6.8-3 Rev. 0 Date report generated:
Wednesday, May 13, 2015 Page 25
GTST AP1000-P18-3.6.9, Rev. 1 pH Adjustment B 3.6.8 BASES SURVEILLANCE REQUIREMENTS (continued)
Agitation of the test solution is prohibited, since an adequate standard for the agitation intensity cannot be specified. The test time of 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> is necessary to allow time for the dissolved TSP to naturally diffuse through the sample solution. In the post LOCA sump area, rapid mixing would occur due to liquid flow, significantly decreasing the actual amount of time before the required pH is achieved.
REFERENCES 1. FSAR Section 6.3.2.1.4, Containment pH Control.
- 2. FSAR Section 6.3.2.2.4, pH Adjustment Baskets.
AP1000 STS B 3.6.8-4 Rev. 0 Date report generated:
Wednesday, May 13, 2015 Page 26