NG-12-0483, License Amendment Request (TSCR-142): Application to Revise Technical Specifications to Adopt TSTF-522, Revise Ventilation System Surveillance Requirements to Operate for 10 Hrs Per Month, Using Consolidated Line Item Improvement Process

License Amendment Request (TSCR-142): Application to Revise Technical Specifications to Adopt TSTF-522, Revise Ventilation System Surveillance Requirements to Operate for 10 Hrs Per Month, Using Consolidated Line Item Improvement Process

ML12356A184
Person / Time
Site:	Duane Arnold
Issue date:	12/21/2012
From:	Richard Anderson NextEra Energy Duane Arnold
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NG-12-0483
Download: ML12356A184 (22)

Text

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December 21,2012 NG-12-0483 10 CFR 50.90 U. S. Nuclear Regular Commission Document Control Desk Washington, DC 20555 Duane Arnold Energy Center Docket No. 50-331 Renewed Op. License No. DPR-49 License Amendment Request (TSCR-142): Application To Revise Technical Specifications To Adopt TSTF-522, "Revise Ventilation System Surveillance Requirements To Operate For 10 Hours Per Month," Using The Consolidated Line Item Improvement Process Sections Affected: 3.6.4.3 and 5.5.7 Pursuant to 10 CFR 50.90, NextEra Energy Duane Arnold, LLC (hereafter NextEra Energy Duane Arnold) hereby requests revision to the Technical Specifications (TS) for the Duane Arnold Energy Center (DAEC).

The proposed amendment would modify the current DAEC TS requirement to operate the Standby Gas Treatment System for 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> on a Frequency specified in the Surveillance Frequency Control Program in accordance with TSTF-522, Revision 0, "Revise Ventilation System Surveillance Requirements to Operate for 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> per Month."

Attachment 1 provides a description and assessment of the proposed changes, the requested confirmation of applicability, and plant-specific verifications. Attachment 2 provides the existing TS pages marked up to show the proposed changes. Attachment 3 provides revised (clean) TS pages. Attachment 4 provides existing TS Bases pages marked up to show the proposed changes for information only.

NextEra Energy Duane Arnold requests NRC review and approval of the proposed license amendment under the Consolidated Line Item Improvement Process (CLlIP). NextEra Energy Duane Arnold is requesting a 30 day grace period to implement this license amendment.

This application has been reviewed by the DAEC Onsite Review Group. A copy of this submittal, along with the 10 CFR 50.92 evaluation of "No Significant Hazards Consideration,"

is being forwarded to our appointed state official pursuant to 10 CFR 50.91.

This letter makes no new commitments or changes to any existing commitments.

If you have any questions or require additional information, please contact Tom Byrne at 319-851-7929.

NextEra Energy Duane Arnold, LLC, 3277 DAEC Road, Palo, IA 52324

Document Control Desk NG-12-0483 Page 2 of 2 I declare under penalty of perjury that the foregoing is true and correct.

Executed on December 21,2012

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Vice President, Duane Arnold Energy Center NextEra Energy Duane Arnold, LLC Attachments: 1. Description and Assessment

2. Proposed Technical Specification Changes (Mark-ups)

3. Revised Technical Specification Pages (Clean, typed)

4. Proposed Technical Specification Bases Changes (Mark-ups, for information only) cc: M. Rasmusson (State of Iowa)

Attachment 1 to NG-12-0483 Page 1 of 6 License Amendment Request (TSCR-142): Application To Revise Technical Specifications To Adopt TSTF-522, Revise Ventilation System Surveillance Requirements To Operate For 10 Hours Per Month, Using The Consolidated Line Item Improvement Process Sections Affected: 3.6.4.3, and 5.

5.7 DESCRIPTION

AND ASSESSMENT

1.0 DESCRIPTION

2.0 ASSESSMENT 2.1 Applicability of Published Safety Evaluation 2.2 Optional Changes and Variations

3.0 REGULATORY ANALYSIS

3.1 No Significant Hazards Consideration

4.0 ENVIRONMENTAL CONSIDERATION

Attachment 1 to NG-12-0483 Page 2 of 6

1.0 DESCRIPTION

The proposed change revises the Surveillance Requirement (SR) which currently requires operating the Standby Gas Treatment (SGT) System, with the electrical heaters operating, for a continuous 10 hour1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> period at a Frequency specified in the Surveillance Frequency Control Program. This Surveillance Requirement (SR 3.6.4.3.1) is revised to require operation of the system for 15 continuous minutes without the heaters operating. The associated Frequency is not proposed to be revised.

In addition, the requirements for testing the SGT System specified in the Ventilation Filter Testing Program (VFTP) in Section 5.5.7, are revised accordingly to remove the electric heater output test (Specification 5.5.7.e) and to increase the specified relative humidity (RH) for the charcoal testing from the current 70% to 95% RH in Specification 5.5.7.c. Deletion of Specification 5.5.7.e causes the subsequent Specifications in this Section to be renumbered accordingly.

The proposed amendment is consistent with TSTF-522, Revision 0, "Revise Ventilation System Surveillance Requirements to Operate for 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> per Month."

2.0 ASSESSMENT 2.1 Applicability of Published Safety Evaluation NextEra Energy Duane Arnold, LLC (hereafter, NextEra Energy Duane Arnold) has reviewed the model safety evaluation dated September 13, 2012 as part of the Federal Register Notice of Availability. This review included a review of the NRC staffs evaluation, as well as the information provided in TSTF-522. As described in the subsequent paragraphs, NextEra Energy Duane Arnold has concluded that the justifications presented in the TSTF-522 proposal and the model safety evaluation prepared by the NRC staff are applicable to the Duane Arnold Energy Center (DAEC) and justify this amendment for the incorporation of the changes to the DAEC TS under the Consolidated Line Item Improvement Process (CLIIP).

2.2 Optional Changes and Variations NextEra Energy Duane Arnold is proposing the following variations from the TS changes described in the TSTF-522, Revision 0, or the applicable parts of the NRC staffs model safety evaluation dated September 13, 2012.

The TSTF-522 section for Boiling Water Reactors (BWRs) included changes for both the SGT System and the Main Control Room Environmental Control (MCREC) System. The DAEC equivalent to the MCREC System is the Standby Filter Unit (SFU) System. However, the approved change to SR 3.7.4.1 in TSTF-522 for the MCREC [SFU] System was previously adopted into the DAEC TS during the conversion to Improved Standard TS (License Amendment 223 - ML021920121) and is, therefore, not included in this request. This is a minor variation that does not adversely impact the Staffs model safety evaluation.

Attachment 1 to NG-12-0483 Page 3 of 6 As noted in the NRCs model safety evaluation, some plants have adopted TSTF-425, which relocated the fixed SR Frequencies to a licensee-controlled program, the Surveillance Frequency Control Program (SFCP). The DAEC TS were revised to adopt the SFCP in License Amendment 280 (ML120110282). Thus, the proposed changes are consistent with the current DAEC licensing basis, the NRCs model safety evaluation, and therefore, do not constitute a deviation from the approved Traveler, but merely an allowable variation.

In addition, NextEra Energy Duane Arnold is proposing to modify the VFTP to remove the requirement to test the SGT System electrical heaters (Specification 5.5.7.e) and to make the corresponding change in Specification 5.5.7.c to increase the testing requirement on the charcoal filters from the current 70% relative humidity (RH) to the more stringent requirement of 95% RH, such that the heaters will no longer be relied upon to remove the additional moisture from the incoming air. This proposed change is consistent with TSTF-522, as the Standard TS (NUREG-1433) on which the Traveler is based, contains both options of with and without humidity control (i.e., electrical heaters) as bracketed versions of the Surveillance Requirement.

The NRCs model safety evaluation also acknowledges both options are allowed, as this is consistent with current Staff guidance in Regulatory Guide 1.52. Therefore, this proposed change is consistent with the approved Traveler and model safety evaluation and does not constitute a technical deviation.

The DAEC TS utilize different numbering than the Standard Technical Specifications on which TSTF-522 was based. Specifically, the VFTP is Section 5.5.7 in the DAEC, which is numbered as Section 5.5.8 in the Standard TS. This difference is an administrative variation and does not affect the applicability of TSTF-522 to the DAEC TS or adversely impact the NRCs model safety evaluation.

3.0 REGULATORY ANALYSIS

3.1 No Significant Hazards Consideration Determination NextEra Energy Duane Arnold requests adoption of an approved change to the Standard Technical Specifications (STS) and plant specific technical specifications (TS), to revise Technical Specification (TS) 3.6.4.3, "Standby Gas Treatment (SGT) System," to revise the Surveillance Requirement (SR) to operate the SGT System, with the electric heaters operating, for a continuous 10 hour1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> period at a Frequency specified by the Surveillance Frequency Control Program (SFCP). The Surveillance Requirement (SR 3.6.4.3.1) is revised to require operation of the systems for 15 continuous minutes, at a Frequency specified by the SFCP, without the electric heaters operating.

In addition, the requirements for testing the SGT System specified in the Ventilation Filter Testing Program (VFTP) in TS Section 5.5.7, are revised accordingly to remove the electric heater output test (Specification 5.5.7.e) and to increase the specified relative humidity (RH) for the charcoal testing from the current 70% to 95% RH in Specification 5.5.7.c.

The deletion of current Specification 5.5.7.e causes the subsequent Specifications in this Section to be renumbered accordingly. This is purely an administrative change.

As required by 10 CFR 50.91(a), an analysis of the issue of no significant hazards consideration is presented below:

Attachment 1 to NG-12-0483 Page 4 of 6

1. Does the proposed change involve a significant increase in the probability or consequences of an accident previously evaluated?

Response: No.

The proposed change replaces an existing Surveillance Requirement to operate the SGT System equipped with electric heaters for a continuous 10 hour1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> period with a requirement to operate the SGT System for 15 continuous minutes without the heaters operating. In addition, the electrical heater output test in the VFTP (Specification 5.5.7.e) is proposed to be deleted and a corresponding change in the charcoal filter testing (Specification 5.5.7.c) be made to require the testing be conducted at a humidity of at least 95% RH, which is more stringent than the current testing requirement of 70% RH.

These systems are not accident initiators and therefore, these changes do not involve a significant increase in the probability of an accident. The proposed system and filter testing changes are consistent with current regulatory guidance for these systems and will continue to assure that these systems perform their design function which may include mitigating accidents. Thus the change does not involve a significant increase in the consequences of an accident.

Therefore, it is concluded that this change does not involve a significant increase in the probability or consequences of an accident previously evaluated.

2. Does the proposed change create the possibility of a new or different kind of accident from any accident previously evaluated?

Response: No.

The proposed change replaces an existing Surveillance Requirement to operate the SGT System equipped with electric heaters for a continuous 10 hour1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> period with a requirement to operate the systems for 15 continuous minutes without the heaters operating. In addition, the electrical heater output test in the VFTP (Specification 5.5.7.e) is proposed to be deleted and a corresponding change in the charcoal filter testing (Specification 5.5.7.c) be made to require the testing be conducted at a humidity of at least 95% RH, which is more stringent than the current testing requirement of 70% RH.

The change proposed for this ventilation system does not change any system operations or maintenance activities. Testing requirements will be revised and will continue to demonstrate that the Limiting Conditions for Operation are met and the system components are capable of performing their intended safety functions. The change does not create new failure modes or mechanisms and no new accident precursors are generated.

Therefore, it is concluded that this change does not create the possibility of a new or different kind of accident from any accident previously evaluated.

3. Does the proposed change involve a significant reduction in a margin of safety?

Response: No.

Attachment 1 to NG-12-0483 Page 5 of 6 The proposed change replaces an existing Surveillance Requirement to operate the SGT System equipped with electric heaters for a continuous 10 hour1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> period with a requirement to operate the systems for 15 continuous minutes without heaters operating.

In addition, the electrical heater output test in the VFTP is proposed to be deleted and a corresponding change in the charcoal filter testing be made to require the testing be conducted at a humidity of at least 95% RH, which is more stringent than the current testing requirement of 70% RH.

The proposed increase to 95% RH in the required testing of the charcoal filters compensates for the function of the heaters, which was to reduce the humidity of the incoming air to below the currently-specified value of 70% RH for the charcoal. The proposed change is consistent with regulatory guidance and continues to ensure that the performance of the charcoal filters is acceptable.

Therefore, it is concluded that this change does not involve a significant reduction in a margin of safety.

Based on the above, NextEra Energy Duane Arnold concludes that the proposed change presents no significant hazards consideration under the standards set forth in 10 CFR 50.92(c),

and, accordingly, a finding of "no significant hazards consideration" is justified.

4.0 ENVIRONMENTAL EVALUATION 10 CFR Section 51.22(c)(9) identifies certain licensing and regulatory actions which are eligible for categorical exclusion from the requirement to perform an environmental assessment. A proposed amendment to an operating license for a facility requires no environmental assessment if operation of the facility in accordance with the proposed amendment would not:

(1) involve a significant hazards consideration; (2) result in a significant change in the types or significant increase in the amounts of any effluents that may be released offsite; and (3) result in a significant increase in individual or cumulative occupational radiation exposure. NextEra Energy Duane Arnold has reviewed this request and determined that the proposed amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR Section 51.22(c)(9).

Pursuant to 10 CFR Section 51.22(b), no environmental impact statement or environmental assessment needs to be prepared in connection with the issuance of the amendment. The basis for this determination follows:

Basis The change meets the eligibility criteria for categorical exclusion set forth in 10 CFR Section 51.22(c)(9) for the following reasons:

1. As demonstrated in the 10 CFR 50.92 evaluation included in Section 3.1, the proposed amendment does not involve a significant hazards consideration.

2. The proposed change does not result in an increase in power level, does not increase the production, nor alter the flow path or method of disposal of radioactive waste or byproducts.

There is no significant change in the types or significant increase in the amounts of any effluents that may be released offsite.

Attachment 1 to NG-12-0483 Page 6 of 6

3. The proposed change does not result in changes in the level of control or methodology used for processing of radioactive effluents or handling of solid radioactive waste nor will the proposal result in any change in the normal radiation levels within the plant. There is no significant increase in individual or cumulative occupational radiation exposure.

Attachment 2 to NG-12-0483 TSCR-142 Technical Specification Pages (Markups) 4 pages to follow

SBGT System 3.6.4.3 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY 15 SR 3.6.4.3.1 Operate each SBGT subsystem for 10 In accordance with continuous hours with heaters operating. the Surveillance Frequency Control minutes Program SR 3.6.4.3.2 ---------------------------NOTE---------------------------

When a SBGT subsystem is placed in an inoperable status solely for the performance of VFTP testing required by this Surveillance on the other subsystem, entry into associated Conditions and Required Actions may be delayed for up to 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />.

Perform required SBGT filter testing in accordance with the Ventilation Filter Testing In accordance with Program (VFTP). the VFTP SR 3.6.4.3.3 Verify each SBGT subsystem actuates on an In accordance with actual or simulated initiation signal. the Surveillance Frequency Control Program SR 3.6.4.3.4 Verify each SBGT filter cooler bypass In accordance with damper can be opened and the fan started. the Surveillance Frequency Control Program TSCR-142 DAEC 3.6-43 Amendment 280

Programs and Manuals 5.5 5.5 Programs and Manuals (continued) 5.5.7 Ventilation Filter Testing Program (VFTP)

A program shall be established to implement the following required testing of Engineered Safety Feature (ESF) filter ventilation systems.

The tests described in Specifications 5.5.7.a and 5.5.7.b shall be performed once per 12 months for standby service, after 720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br /> of system operation, following significant painting, fire or chemical release in any ventilation zone communicating with the system, after any structural maintenance on the system housing, and after each partial or complete replacement of the HEPA filter train or charcoal adsorber, respectively.

The test described in Specification 5.5.7.c shall be performed once per 12 months for standby service, after 720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br /> of system operation and following significant painting, fire or chemical release in any ventilation zone communicating with the system.

The tests described in Specifications 5.5.7.d and 5.5.7.e shall be performed annually.

e For the SBGT System only, the test described in Specification 5.5.7.f shall be performed after each complete or partial replacement of the HEPA filter bank and after any structural maintenance on the system housing.

f For the SBGT System only, the test described in Specification 5.5.7.g shall be performed in conjunction with the tests described in Specification 5.5.7.c.

a. Demonstrate for each of the ESF systems that an inplace test of the HEPA filters shows a penetration and system bypass at the value specified and at the system flowrate specified below:

ESF Ventilation System Penetration Flowrate (cfm) and System Bypass (%)

SBGT System < 0.1 3600 - 4400 SFU System < 1.0 900 - 1100 (continued)

TSCR-142 DAEC 5.0-12 Amendment 223

Programs and Manuals 5.5 5.5 Programs and Manuals 5.5.7 Ventilation Filter Testing Program (VFTP) (continued)

b. Demonstrate for each of the ESF systems that an inplace test of the charcoal adsorber shows a penetration and system bypass at the value specified and at the system flowrate specified below:

ESF Ventilation System Penetration Flowrate (cfm) and System Bypass (%)

SBGT System < 0.1 3600 - 4400 SFU System < 1.0 900 - 1100

c. Demonstrate for each of the ESF systems that a laboratory test of a sample of the charcoal adsorber, when obtained as described in Regulatory Guide 1.52 Revision 2, shows the methyl iodide penetration less than the value specified below when tested in accordance with ASTM D3803-1989 at a temperature of 30°C and the relative humidity specified below:

ESF Ventilation System Penetration Relative Humidity 95%

SBGT System < 0.5% 70%

SFU System < 5.0% 95%

d. Demonstrate for each of the ESF systems that the pressure drop across the combined HEPA filters, the prefilters (SBGT System only), and the charcoal adsorbers is less than the value specified below and at the system flowrate specified as follows:

(continued)

TSCR-142 DAEC 5.0-13 Amendment No. 235

Programs and Manuals 5.5 5.5 Programs and Manuals 5.5.7 Ventilation Filter Testing Program (VFTP) (continued)

ESF Ventilation System Delta P (inches wg) Flowrate (cfm)

SBGT System < 11 3600 - 4400 SFU System < 6 900 - 1100

e. Demonstrate that the heaters for the SBGT System dissipate 22 kW.

e

f. Demonstrate that air distribution is uniform within 20% of averaged flow per unit across SBGT System HEPA filters.

f

g. Visually inspect the SBGT System charcoal adsorber to ensure no flow blockage has occurred.

The provisions of SR 3.0.2 and SR 3.0.3 are applicable to the VFTP test frequencies.

5.5.8 Explosive Gas and Storage Tank Radioactivity Monitoring Program This program provides controls for potentially explosive gas mixtures contained in the Offgas System downstream of the recombiners and the quantity of radioactivity contained in unprotected outdoor liquid storage tanks. The liquid radwaste quantities shall be determined in accordance with Standard Review Plan, Section 15.7.3, Postulated Radioactive Release due to Tank Failures.

The program shall include:

a. The limits for concentrations of hydrogen in the Offgas System downstream of the recombiners and a surveillance program to ensure the limits are maintained. Such limits shall be appropriate to the systems design criteria (i.e., whether or not the system is designed to withstand a hydrogen explosion);

(continued)

TSCR-142 DAEC 5.0-14 Amendment 223

Attachment 3 to NG-12-0483 TSCR-142 Technical Specification Pages (Clean, typed) 4 pages to follow

SBGT System 3.6.4.3 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.6.4.3.1 Operate each SBGT subsystem for 15 In accordance with continuous minutes. the Surveillance Frequency Control Program SR 3.6.4.3.2 ---------------------------NOTE---------------------------

When a SBGT subsystem is placed in an inoperable status solely for the performance of VFTP testing required by this Surveillance on the other subsystem, entry into associated Conditions and Required Actions may be delayed for up to 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />.

Perform required SBGT filter testing in accordance with the Ventilation Filter Testing In accordance with Program (VFTP). the VFTP SR 3.6.4.3.3 Verify each SBGT subsystem actuates on an In accordance with actual or simulated initiation signal. the Surveillance Frequency Control Program SR 3.6.4.3.4 Verify each SBGT filter cooler bypass In accordance with damper can be opened and the fan started. the Surveillance Frequency Control Program DAEC 3.6-43 Amendment

Programs and Manuals 5.5 5.5 Programs and Manuals (continued) 5.5.7 Ventilation Filter Testing Program (VFTP)

A program shall be established to implement the following required testing of Engineered Safety Feature (ESF) filter ventilation systems.

The tests described in Specifications 5.5.7.a and 5.5.7.b shall be performed once per 12 months for standby service, after 720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br /> of system operation, following significant painting, fire or chemical release in any ventilation zone communicating with the system, after any structural maintenance on the system housing, and after each partial or complete replacement of the HEPA filter train or charcoal adsorber, respectively.

The test described in Specification 5.5.7.c shall be performed once per 12 months for standby service, after 720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br /> of system operation and following significant painting, fire or chemical release in any ventilation zone communicating with the system.

The test described in Specification 5.5.7.d shall be performed annually.

For the SBGT System only, the test described in Specification 5.5.7.e shall be performed after each complete or partial replacement of the HEPA filter bank and after any structural maintenance on the system housing.

For the SBGT System only, the test described in Specification 5.5.7.f shall be performed in conjunction with the tests described in Specification 5.5.7.c.

a. Demonstrate for each of the ESF systems that an inplace test of the HEPA filters shows a penetration and system bypass at the value specified and at the system flowrate specified below:

ESF Ventilation System Penetration Flowrate (cfm) and System Bypass (%)

SBGT System < 0.1 3600 - 4400 SFU System < 1.0 900 - 1100 (continued)

DAEC 5.0-12 Amendment

Programs and Manuals 5.5 5.5 Programs and Manuals 5.5.7 Ventilation Filter Testing Program (VFTP) (continued)

b. Demonstrate for each of the ESF systems that an inplace test of the charcoal adsorber shows a penetration and system bypass at the value specified and at the system flowrate specified below:

ESF Ventilation System Penetration Flowrate (cfm) and System Bypass (%)

SBGT System < 0.1 3600 - 4400 SFU System < 1.0 900 - 1100

c. Demonstrate for each of the ESF systems that a laboratory test of a sample of the charcoal adsorber, when obtained as described in Regulatory Guide 1.52 Revision 2, shows the methyl iodide penetration less than the value specified below when tested in accordance with ASTM D3803-1989 at a temperature of 30°C and the relative humidity specified below:

ESF Ventilation System Penetration Relative Humidity SBGT System < 0.5% 95%

SFU System < 5.0% 95%

d. Demonstrate for each of the ESF systems that the pressure drop across the combined HEPA filters, the prefilters (SBGT System only), and the charcoal adsorbers is less than the value specified below and at the system flowrate specified as follows:

(continued)

DAEC 5.0-13 Amendment No.

Programs and Manuals 5.5 5.5 Programs and Manuals 5.5.7 Ventilation Filter Testing Program (VFTP) (continued)

ESF Ventilation System Delta P (inches wg) Flowrate (cfm)

SBGT System < 11 3600 - 4400 SFU System < 6 900 - 1100

e. Demonstrate that air distribution is uniform within 20% of averaged flow per unit across SBGT System HEPA filters.

f. Visually inspect the SBGT System charcoal adsorber to ensure no flow blockage has occurred.

The provisions of SR 3.0.2 and SR 3.0.3 are applicable to the VFTP test frequencies.

5.5.8 Explosive Gas and Storage Tank Radioactivity Monitoring Program This program provides controls for potentially explosive gas mixtures contained in the Offgas System downstream of the recombiners and the quantity of radioactivity contained in unprotected outdoor liquid storage tanks. The liquid radwaste quantities shall be determined in accordance with Standard Review Plan, Section 15.7.3, Postulated Radioactive Release due to Tank Failures.

The program shall include:

a. The limits for concentrations of hydrogen in the Offgas System downstream of the recombiners and a surveillance program to ensure the limits are maintained. Such limits shall be appropriate to the systems design criteria (i.e., whether or not the system is designed to withstand a hydrogen explosion);

(continued)

DAEC 5.0-14 Amendment

Attachment 4 to NG-12-0483 TSCR-142 Technical Specification BASES pages (Markups)

FOR INFORMATION ONLY 3 pages to follow

SBGT System B 3.6.4.3 B 3.6 CONTAINMENT SYSTEMS B 3.6.4.3 Standby Gas Treatment (SBGT) System BASES BACKGROUND The SBGT System is required by the UFSAR (Ref. 1). The function of the SBGT System is to ensure that radioactive materials that leak from the primary containment into the secondary containment following a Design Basis Accident (DBA) are filtered and adsorbed prior to exhausting to the environment.

The SBGT System consists of two fully redundant subsystems, each with its own set of ductwork, dampers, charcoal filter train, and controls.

Each charcoal filter train consists of (components listed in order of the direction of the air flow):

a. A demister or moisture separator;

b. An electric heater; b

c. A prefilter; c

d. A High Efficiency Particulate Air (HEPA) filter; d

e. A charcoal adsorber; e

f. A second HEPA filter; and f

g. A centrifugal fan.

HEPA filters are installed before and after the charcoal adsorbers to minimize potential release of particulates to the environment and to prevent clogging of the iodine adsorbers. The charcoal adsorbers are installed to reduce the potential release of radioiodine to the environment. The in-place testing of the HEPA filters and charcoal adsorbers is performed under the DAEC Ventilation Filter Testing Program (ITS 5.5.7). If the efficiencies of the HEPA filters and charcoal adsorbers are as specified, the resulting doses will be less than the 10 CFR 50.67 guidelines for the accidents analyzed, as the UFSAR Section 15.2.1 for the loss-of-coolant accident shows compliance with 10 CFR 50.67 (continued) 142 DAEC B 3.6-90 TSCR-044A

SBGT System B 3.6.4.3 BASES BACKGROUND guidelines with an assumed efficiency of 99% for the adsorber.

(continued) Operation of the fans significantly different from the design flow envelope will change the removal efficiency of the HEPA filters and charcoal adsorbers.

The sizing of the SBGT System equipment and components is based on the results of an infiltration analysis, as well as an exfiltration analysis of the secondary containment. The internal pressure of the SBGT System boundary region is maintained at a negative pressure of at least 0.25 inches water gauge (as determined by averaging pressure readings from different faces of the Secondary Containment boundary) when the system is in operation, which represents an internal pressure that ensures zero exfiltration of air from the building when exposed to calm wind conditions (< 15 mph). Maintaining a negative pressure of 0.25 inches water gauge under calm wind conditions ensures a negative pressure under worst case conditions. Therefore, a negative pressure of 0.25 inches water gauge includes some margin to a negative pressure that ensures zero exfiltration.

The demister is provided to remove entrained water in the air, while the electric heater reduces the relative humidity of the airstream to less than 70% (Ref. 2). The prefilter removes large particulate matter, while the HEPA filter removes fine particulate matter and protects the charcoal from fouling. The charcoal adsorber removes gaseous elemental iodine and organic iodides, and the final HEPA filter collects any carbon fines exhausted from the charcoal adsorber.

The SBGT System automatically starts and operates in response to secondary containment isolation actuation signals indicative of conditions or an accident that could require operation of the system. Following initiation, both charcoal filter train fans start.

Upon verification that both subsystems are operating, the redundant subsystem is normally shut down.

APPLICABLE The design basis for the SBGT System is to mitigate the SAFETY consequences of a loss of coolant accident (Ref. 3). For all ANALYSES events analyzed, the SBGT subsystem is shown to be automatically initiated to reduce, via filtration and adsorption, the radioactive material released to the environment. Only one of the two SBGT subsystems is needed to clean up the reactor building atmosphere upon containment isolation.

The SBGT System satisfies Criterion 3 of 10 CFR 50.36(c)(2)(ii).

(continued) 142 DAEC B 3.6-91 TSCR-037

SBGT System B 3.6.4.3 BASES ACTIONS E.1 (continued)

When two SBGT subsystems are inoperable, if applicable, actions must Immediately be initiated to suspend OPDRVs in order to minimize the probability of a vessel draindown and subsequent potential for fission product release. Actions must continue until OPDRVs are suspended.

LCO 3.0.3 is not applicable in MODE 4 or 5 when OPDRVs can occur. Required Action E.1 has been modified by a Note stating that LCO 3.0.3 is not applicable.

SURVEILLANCE SR 3.6.4.3.1 REQUIREMENTS Operating each SBGT subsystem ensures that both subsystems are OPERABLE and that all associated controls are functioning properly. It also ensures that blockage or fan or motor failure, can be detected for corrective action. Periodically operation with the heaters on (automatic heater cycling to maintain temperature) for 10 continuous hours eliminates moisture on the adsorbers and HEPA filters. The Surveillance Frequency is controlled under the Surveillance Frequency Control Program. The Frequency is sufficient to ensure potential moisture build-up does not impact the adsorption and filtering function. The Frequency was also developed in consideration of the known reliability of fan motors and controls and the redundancy available in the system, however these components are not the most-limiting for overall system reliability at this SR Frequency. It is not necessary to run the system for the full 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> to demonstrate Operability following maintenance, if that maintenance did not affect the filters and charcoal beds.

SR 3.6.4.3.2 This SR verifies that the required SBGT filter testing is performed in accordance with Specification 5.5.7, Ventilation Filter Testing Program (VFTP). The VFTP includes testing HEPA filter performance, charcoal adsorber efficiency, system flow capability, and the physical properties of the activated charcoal (general use and following specific operations). Specific test frequencies and additional information are discussed in detail in the VFTP.

(continued) 142 DAEC B 3.6-94 TSCR-120