ML042380498

Technical Specifications Change 03-11 Deletion of Vacuum Relief Flow Requirements from Auxiliary Building Gas Treatment System Surveillance Requirements

ML042380498
Person / Time
Site:	Sequoyah
Issue date:	08/12/2004
From:	Salas P Tennessee Valley Authority
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
TS 03-11, TVA-SQN-TS-03-11
Download: ML042380498 (17)

Text

Tennessee Valley Authority, Post Office Box 2000, Soddy-Daisy, Tennessee 37384-2000 August 12, 2004 TVA-SQN-TS-03-11 10 CFR 50.90 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555-0001 Gentlemen:

In the Matter of ) Docket Nos. 50-327 Tennessee Valley Authority ) 50-328 SEQUOYAH NUCLEAR PLANT (SQN) - UNITS 1 AND 2 - TECHNICAL SPECIFICATIONS (TS) CHANGE 03-11 "DELETION OF VACUUM RELIEF FLOW REQUIREMENTS FROM AUXILIARY BUILDING GAS TREATMENT SYSTEM (ABGTS) SURVEILLANCE REQUIREMENTS" Pursuant to 10 CFR 50.90, TVA is submitting a request for a TS change (TS-03-11) to Licenses DPR-77 and DPR-79 for SQN Units 1 and 2. The proposed TS change will revise Surveillance Requirement 4.7.8.d.3 by removing the vacuum relief flow portion. The proposed revision removes criteria from the surveillance that is not necessary to verify the operability of the ABGTS. The Bases associated with the ABGTS will be revised to remove discussions regarding the vacuum relief flow portion of this surveillance as part of this effort.

TVA has determined that there are no significant hazards considerations associated with the proposed change and that the TS change qualifies for categorical exclusion from environmental review pursuant to the provisions of 10 CFR 51.22(c)(9).

Pated w mcnydd p~pe

U.S. Nuclear Regulatory Commission Page 2 August 12, 2004 Additionally, in accordance with 10 CFR 50.91(b)(1), TVA is sending a copy of this letter and enclosures to the Tennessee State Department of Public Health.

TVA does not have specific schedule needs for this proposed change and processing can be pursued as appropriate. TVA requests that the implementation of the revised TS be within 45 days of NRC approval.

There are no commitments contained in this submittal.

If you have any questions about this change, please contact me at 843-7170 or Jim Smith at 843-6672.

I declare under penalty of perjury that the foregoing is true and correct. Executed on this JA_ day of A2.vOlt.

Sincerely, Pedro Salas Manager of Licensing and Industry Affairs

Enclosures:

1. TVA Evaluation of the Proposed Changes

2. Proposed Technical Specifications Changes (mark-up)

3. Changes to Technical Specifications Bases Pages cc: See page 3

U.S. Nuclear Regulatory Commission Page 3 August 12, 2004 Enclosures cc (Enclosures):

Framatome ANP, Inc.

P. 0. Box 10935 Lynchburg, Virginia 24506-0935 ATTN: Mr. Frank Masseth Mr. Lawrence E. Nanney, Director Division of Radiological Health Third Floor L&C Annex 401 Church Street Nashville, Tennessee 37243-1532 Mr. Robert J. Pascarelli, Senior Project Manager U.S. Nuclear Regulatory Commission Mail Stop O-7A15 One White Flint North 11555 Rockville Pike Rockville, Maryland 20852-2739

ENCLOSURE 1 TENNESSEE VALLEY AUTHORITY SEQUOYAH NUCLEAR PLANT (SQN)

UNITS 1 AND 2

1.0 DESCRIPTION

This'letter is a request to amend Operating Licenses DPR-77 and DPR-79 for SQN Units 1 and 2. The proposed change would revise Surveillance Requirement (SR) 4.7.8.d.3 by removing the vacuum relief flow portion. The proposed revision removes criteria from the surveillance that is not necessary to verify the operability of the auxiliary building gas treatment system (ABGTS). The proposed'change will eliminate confusion regarding the basis for the vacuum relief-flow with respect to ABGTS operability. The Bases associated with the ABGTS will be revised to remove discussions regarding the vacuum relief flow portion of this surveillance as part of this effort. The proposed'changes are consistent with the latest version of the standard'technical specifications (TSs)

(NUREG-1431, Revision 3) for ABGTS testing.

2.0 PROPOSED CHANGE

The proposed change will revise SR 4.7.8.d.3 for ABGTS operability verification. This change will remove the following words from the surveillance: -

"a vacuum relief flow greater than 2000 cfm and" The resulting requirement for SR 4.7.8.d.3 is proposed to be:

"Verifying that the system maintains the spent fuel storage area and the ESF pump rooms at a pressure equal to or more negative than minus 1/4 inch water gauge relative the outside atmosphere while maintaining a total system flow of 9000 cfm +/- 10%."

The Bases for the ABGTS requirements will also be revised to remove specific discussions that currently provide clarifications for the vacuum relief flow with regard to ABGTS-operability. The deleted Bases discussion is as follows:

"The minimum vacuum relief flow requirement in TS Surveillance Requirement 4.7.8.d.3 is for test purposes only. It is intended to demonstrate an acceptable level of ABGTS performance margin by simulating an ABSCE boundary breach. The inability to meet the specified minimum test condition under other El-i

circumstances does not challenge the operability of the ABGTS."

In summary, the proposed change will remove an unnecessary statement in SR 4.7.8.d.3 that is not required to verify operability of the ABGTS. This removal of the vacuum relief flow criteria will reduce potential confusion for verifications of ABGTS operability. The Bases deletion supports this revision by removing discussions that were included to address this unnecessary statement. The proposed change is consistent with NUREG-1431, Revision 3.

3.0 BACKGROUND

The ABGTS is a fully redundant air cleanup network provided to reduce radioactive nuclide releases from the auxiliary building secondary containment enclosure (ABSCE) during accidents. This system draws air from various parts of the auxiliary building to establish a negative pressure in the auxiliary building with respect to outside atmosphere. The air is directed to air cleanup equipment before being discharged through the shield building vent.

The rated capacity of each redundant air cleanup unit in this gas treatment system is 9000 cubic feet per minute (cfm).

Two air flow control modules, each assigned to a particular air cleanup unit, are utilized in the ABGTS. These contain a differential pressure sensor and transmitter, control circuitry, and an air operated modulating damper. These two air flow control modules provide the capability for keeping the pressure within the ABSCE at or more negative than 1/4 inch of water below atmospheric. The modulating damper is controlled by the differential pressure transmitter to adjust the amount of outside air introduced into the duct network just upstream of the constant capacity fan described above.

Such action will bring in sufficient outside air to keep the fan at its rated flow and to establish and keep the desired negative pressure level.

Operation of the ABGTS begins automatically upon receipt of a:

1. Phase A containment isolation signal from either reactor unit, or a

2. High radiation signal from the fuel handling area radiation monitors, or a

3. High radiation signal from the auxiliary building exhaust vent monitor, or a

4. High temperature signal from the auxiliary building air intakes.

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The design bases for the ABGTS are:

1. To establish and keep an air pressure that is below atmospheric within the portion of the auxiliary building serving as a secondary containment enclosure during accidents.

2. To reduce the concentration of radioactive nuclides in air releases from the ABSCE to the environs during accidents to levels sufficiently low to keep the site boundary dose rate below the 10 CFR 100 guideline value.

3. To minimize the spreading of airborne radioactivity within the auxiliary building following an accidental release in the fuel handling areas.

During the original licensing of the SQN units, the vacuum relief flow criterion was included in the TSs. This provision was not found in the version of the standard TSs that was in effect at that time and the reason for including this criterion cannot be determined. Since that time, there does not appear to be any basis for this provision to be included in the surveillance for verification of the operability of the ABGTS. Current standard TSs (NUREG-1431, Revision 3) do not include requirements for vacuum relief flow as a criterion for establishing acceptable testing methods for ABGTS operability.

4.0 TECHNICAL ANALYSIS

The proposed TS change will eliminate the criterion regarding minimum vacuum relief flow from the operability surveillance for the ABGTS. It is believed that the vacuum relief flow provision was intended to demonstrate an acceptable level of ABGTS performance margin by requiring an ABSCE boundary leakage rate well below the minimum allowed. The ability to establish a 2000 cfm vacuum relief flow, while maintaining the required negative pressure and total required flow, is a good indication of ABGTS and ABSCE performance, but is not required for the ABGTS to perform its accident mitigation function. The design function of the vacuum relief is to vary the amount of outside air on the suction side of the fan in order to control ABSCE vacuum and maintain the fan at rated flow. While a 2000 cfm or more vacuum relief flow would indicate that the boundary in-leakage is well below the minimum allowed leakage, it is not required to verify operability of the ABGTS system. The ABGTS can perform required safety functions if the system can maintain the

-0.25-inch water gauge condition or more negative in the ABSCE at a total flow of 9000 cfm plus or minus 10 percent regardless of the vacuum relief flow rate.

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The proposed change will remove this overly conservative criterion from the TS surveillance. However, SQN surveillance procedures continue to utilize the vacuum relief flow as an indication of potential ABSCE degradation that needs to be evaluated. While vacuum relief flow is not associated with system operability in accordance with the proposed TS surveillance, TVA will continue to utilize decreasing vacuum relief flow as an indicator of potentially degrading leakage conditions and initiate corrective actions when appropriate. This is an acceptable approach since the ABGTS safety functions remain fully capable of mitigating postulated accident conditions as long as the negative pressure requirements can be maintained. The current pressure and system flow requirements of the surveillance are not affected by the proposed change. The latest standard TSs (NUREG-1431) do not include the vacuum relief flow criterion in the provisions for this system.

TVA has evaluated the potential dose impacts resulting from the proposed change. The events potentially affected are the loss of coolant and the fuel handling accidents as these are expected to release radioactivity to the auxiliary building.

These accidents are discussed in the Update Final Safety Analysis Report Section 15.5. The proposed change continues to maintain the requirement for the ABGTS to control ABSCE pressure at a negative pressure and therefore, assures radioactive material will be processed through the filter trains. Since this change will not alter this function the offsite dose is not affected.

The proposed change does not alter the system performance or operating provisions such that the safety function is affected. The removal of this provision does not weaken the operability verifications for this system below an acceptable level. The proposed surveillance continues to ensure the safety function as well as meeting the recommendations of NUREG-1431 for acceptable methods to maintain the ABGTS safety function. Therefore, the proposed change is acceptable from a nuclear safety standpoint and will not impact the health and safety of the public.

5.0 REGULATORY SAFETY ANALYSIS The proposed change would revise Surveillance Requirement 4.7.8.d.3 by removing the vacuum relief flow.portion. The proposed revision removes criteria from the surveillance that is not necessary to verify the operability of the auxiliary building gas treatment system (ABGTS). The proposed change will eliminate confusion regarding the basis for the vacuum relief flow with respect to ABGTS operability. The Bases associated with the ABGTS system will be revised to remove discussions regarding the vacuum relief flow portion of this surveillance as part of this effort. The proposed changes E1-4

are consistent with the latest version of the standard technical specifications (TSs) (NUREG-1431, Revision 3) for ABGTS testing.

5.1 No Significant Hazards Consideration TVA has evaluated whether or not a significant hazards consideration is involved with the proposed amendments by focusing on the three standards set forth in 10 CFR 50.92, "Issuance of amendment," as discussed below:

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

Response: No.

The proposed change removes an overly restrictive criterion for vacuum relief flow as part of the ABGTS operability verification. This criterion is not required for the verification of ABGTS operability and therefore, the removal does not reduce the associated safety function. No system modification or operating practices are changed by the proposed revision. The accident mitigation functions of the ABGTS will not be adversely affected by the proposed removal and offsite dose potential is not increased. Therefore, the proposed 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 does not result in the alteration of plant equipment or components or the modification of operating requirements for plant systems. Additionally, the ABGTS functions serve to mitigate accident conditions and are not considered a source for accident generation.

Therefore, the proposed change does not create the possibility of a new or different kind of accident from any previously evaluated.

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

Response: No.

The proposed removal of an unnecessary criterion from the ABGTS surveillance will not result in a change to plant setpoints that function to maintain the safety margins. The ABGTS will continue to provide the required negative pressure conditions for the auxiliary building during accident conditions to maintain acceptable dose conditions. The actuation of safety features for accident mitigation will not be affected by the proposed changes. Therefore, the proposed change does not involve a significant reduction in a margin of safety.

Based on the above, TVA concludes that the proposed amendment(s) present 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.

5.2 Applicable Regulatory Requirements/Criteria Section 182a of the Atomic Energy Act requires applicants for nuclear power plant operating licenses to include TSs as part of the license. The Commission's regulatory requirements related to the content of the TS are contained in Title 10, Code of Federal Regulations (10 CFR), Section 50.36. The TS requirements in 10 CFR 50.36 include the following categories: (1) safety limits, limiting safety systems settings and control settings, (2) limiting conditions for operation (LCO), (3) surveillance requirements (SRs), (4) design features, and (5) administrative controls. The SRs for the ABGTS are included in the TS in accordance with 10 CFR 50.36(c)(3), "Surveillance Requirements."

As stated in 10 CFR 50.59(c)(1)(i), a licensee is required to submit a license amendment pursuant to 10 CFR 50.90 if a change to the TS is required.

Furthermore, the requirements of 10 CFR 50.59 necessitate that U.S. Nuclear Regulatory Commission (NRC) approve the TS changes before the changes are implemented. TVA's submittal meets the requirements of 10 CFR 50.59(c)(1)(i) and 10 CFR 50.90.

NUREG-1431, Revision 3, "Standard Technical Specifications Westinghouse Plants," provides generic recommendations for requirements associated with the E1-6

operation of Westinghouse Electric Company designed nuclear power plants. NUREG-1431 contains specifications for the emergency core cooling system pump room exhaust air cleanup system which is equivalent to Sequoyah Nuclear Plant's (SQN's) ABGTS provisions in TS 3.7.8. The proposed change to the SQN TSs is consistent with the surveillance provisions for this system in the NUREG and provides the same assurance for availability of the associated safety function. The proposed change is consistent with and meets the intent in NUREG-1431 for operability and SRs for ABGTS.

Title 10, "Energy," of the CFR, Part 100, "Reactor Site Criteria," establishes approval requirements for proposed sites for stationary power and testing reactors. Within this part, the limits for total radiation dose to the whole body and the total radiation dose to the thyroid from iodine exposure is contained. The proposed change to the SQN TSs removes a provision for ABGTS operability that is not required to verify the ability of the associated safety function. The safety function of the ABGTS is to ensure acceptable leakage of radioactive material to the outside environs. Since the purpose of the ABGTS is to ensure the ability to maintain the 10 CFR 100 limits during accident conditions, removing an unnecessary surveillance provision continues to meet this intent.

10 CFR 50, Appendix A, "General Design Criteria for Nuclear Power Plants," Criterion 60, "Control of Releases of Radioactive Materials to the Environment,"

and Criterion 61, "Fuel Storage and Handling and Radioactivity Control," provide requirements for systems that control the release of radioactive materials during normal and accident conditions.

Criterion 60 states that the plant design shall include means to control suitably the release of radioactive materials in gaseous and liquid effluents.

Criterion 61 states that the systems shall be designed with appropriate containment, confinement, and filtering systems. The ABGTS supports these requirements by providing post-accident conditions that limit the release of radioactive materials. The proposed change to remove the vacuum relief flow requirement will not reduce the effectiveness of this function. This is based on the pressure and flow for the ABGTS not being altered and the proposed change only eliminating the overly restrictive vacuum flow provision. This flow is not an indication of system capability if the total ABGTS flow and auxiliary building pressure are within limits. Therefore, the E1-7

proposed cha~nge will not result in a deviation from the expectations of these general design criteria.

In conclusion, based on the considerations discussed above, (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.

6.0 ENVIRONMENTAL CONSIDERATION

A review has determined that the proposed amendment would change a requirement with respect to installation or use of a facility component located within the restricted area, as defined in 10 CFR 20, or would change an inspection or SR.

However, the proposed amendment does not involve (i) a significant hazards consideration, (ii) a significant change in the types or significant increase in the amounts of any effluent that may be released offsite, or (iii) a significant increase in individual or cumulative occupational radiation exposure. Accordingly, the proposed amendment meets the eligibility criterion for categorical exclusion set forth in 10 CFR 51.22(c)(9). Therefore, pursuant to 10 CFR 50.22(b),

no environmental impact statement or environmental assessment needs to be prepared in connection with the proposed amendment.

7.0 REFERENCE NUREG-1431, Revision 3, "Standard Technical Specifications Westinghouse Plants," June 2004 E1-8

ENCLOSURE 2 TENNESSEE VALLEY AUTHORITY, SEQUOYAH NUCLEAR PLANT (SQN)

UNITS 1 AND 2 Proposed Technical Specification Changes (mark-up)

I. AFFECTED PAGE LIST Unit 1 3/4 7-20 Unit 2 3/4 7-20 II. MARKED PAGES See attached.

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PLANT SYSTEMS SURVEILLANCE REQUIREMENTS (Continued)

c. After every 720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br /> of charcoal adsorber operation by verifying within 31 days after removal that a laboratory analysis of representative carbon sample obtained in accordance with Regulatory Position C.6.b of Regulatory Guide 1.52, Revision 2, March 1978, shows the methyl iodide penetration less than 2.5% when tested in accordance with ASTM D3803-1989 at a temperature of 300 C (860 F) and a relative humidity of 70%.

d. At least once per 18 months by:

1. Verifying that the pressure drop across the combined HEPA filters and charcoal adsorber banks is less than 3 inches Water Gauge while operating the filter train at a flow rate of 9000 cfm +/- 10%.

2. Verifying that the filter trains start on a Containment Phase A Isolation test signal.

3. Verifying that the system maintains the spent fuel storage area and the ESF pump rooms at a pressure equal to or more negative t~, oI J

4. Verifying that the heaters dissipate 32 +/- 3.2 kw ested in accordance with ANSI N510-1975.

e. After each complete or partial replacement of a HEPA filter bank by verifying that the HEPA filter banks remove greater than or equal to 99.95% of the DOP when they are tested in-place in accordance with ANSI N510-1975 while operating the system at a flow rate of 9000 cfm +/- 10%.

f. After each complete or partial replacement of a charcoal adsorber bank by verifying that the charcoal adsorbers remove greater than or equal to 99.95% of a halogenated hydrocarbon refrigerant test gas when they are tested in-place in accordance with ANSI N510-1975 while operating the system at a flow rate of 9000 cfm +/- 10%.

November 2, 2000 SEQUOYAH - UNIT 1 3/4 7-20 Amendment Nos. 12, 88, 103, 122, 263 E2 -2

PLANT SYSTEMS SURVEILLANCE REQUIREMENTS (Continued)

c. After every 720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br /> of charcoal adsorber operation by verifying within 31 days after removal that a laboratory analysis of representative carbon sample obtained in accordance with Regulatory Position C.6.b of Regulatory Guide 1.52, Revision 2, March 1978, shows the methyl iodide penetration less than 2.5% when tested in accordance with ASTM D3803-1989 at a temperature of 300C (860 F) and a relative humidity of 70%.

d. At least once per 18 months by:.

1. Verifying that the pressure drop across the combined HEPA filters and charcoal adsorber banks is less than 3 inches Water Gauge while operating the filter train at a flow rate of 9000 cfm +/- 10%.

2. Verifying that the filter trains start on a Containment Phase A Isolation test signal.

3. Verifying that the system maintains the spent fuel storage area and the ESF pump rooms at a pressure equal to or more negatvet eda

< _ ~~gaii --- vcurelief flxv greaterhaF t fm

^00nd toal ystm flow of 9000 cfm +/- 10%.

4. Verifying that the heaters dissipate 32 +/- 3.2 kw when tested in accordance with ANSI N510-1975.

e. After each complete or partial replacement of a HEPA filter bank by verifying that the HEPA filter banks remove greater than or equal to 99.95% of the DOP when they are tested in-place in accordance with ANSI N510-1975 while operating the system at a flow rate of 9000 cfm i 10%.

f. After each complete or partial replacement of a charcoal adsorber bank by verifying that the charcoal adsorbers remove greater than or equal to 99.95% of a halogenated hydrocarbon refrigerant test gas when they are tested in-place in accordance with ANSI N510-1975 while operating the system at a flow rate of 9000 cfm +/- 10%.

November 2, 2000 SEQUOYAH - UNIT 2 3/4 7-20 Amendment No. 77, 111, 254 E2-3

ENCLOSURE 3 TENNESSEE VALLEY AUTHORITY SEQUOYAH NUCLEAR PLANT (SQN)

UNITS 1 AND 2 Changes to Technical Specifications Bases Pages I. AFFECTED PAGE LIST Unit I B 3/4 7-5 Unit 2 B 3/4 7-5 II. MARKED PAGES See attached.

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PLANT SYSTEMS BASES 314.7.8 AUXILIARY BUILDING GAS TREATMENT SYSTEM The OPERABILITY of the auxiliary building gas treatment system ensures that radioactive materials leaking from the ECCS equipment following a LOCA are filtered prior to reaching the environment. The operation of this system and the resultant effect on offsite dosage calculations was assumed in the accident analyses. ANSI N510-1975 will be used as a procedural guide for surveillance testing. Cumulative operation of the system with the heaters on for 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> over a 31 day period is sufficie educe the buildup of moisture on the adsorbers and H filters.

}The minimum vacuumR rolisf f19W F89Wiromont in T-9utilac RoqUireomoRt 4.7.84d3 is. fo Bet PUPr:,eSnr cRIY anist ir, Wendedlo te drunnyrtWr~ RnaGrspt-ale Wrx-ol of ART-S errmanRte FRa iA h rsnnikatino e A /aR r a.

buRd-wy berea~h Tnhe ~blity to Re~ he r6narif;4n FRniFRnUoR t GGnSpt;in e

tnlrnth--F GiFouirnstanRG blond Ret Ghalle^o-the eperability of the AEBGT-9.

3/4.7.9 SNUBBERS This specification is deleted.

August 28, 1998 SEQUOYAH - UNIT 1 B 3/4 7-5 Amendment No. 12, 235 E3-2

PLANT SYSTEMS BASES 3/4.7.8 AUXILIARY BUILDING GAS TREATMENT SYSTEM The OPERABILITY of the auxiliary building gas treatment system ensures that radioactive materials leaking from the ECCS equipment following a LOCA are filtered prior to reaching the environment. The operation of this system and the resultant effect on offsite dosage calculations was assumed in the accident analyses. ANSI N510-1975 will be used as a procedural guide for surveillance testing.

Cumulative operation of the system with the heaters on for 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> over a 31 day period is sufficient to reduce the buildup 1.10;'o -orbers and HEPA f Z r UFl e6 GRIt. Itl i6iR za GRfFat aR aG^eptable

-- rr level ef A13GTSpe-^fermnaG Fn aFon rT by---

Isrmillnnao ABSEr bG-d~ , We.a= h. The inability ton Meet ton r^^ G;f9^^ minoilmu test r e-Ad-ifien 3/4.7.9 SNUBBERS This specification is deleted.

August 28, 1998 SEQUOYAH - UNIT 2 B 3/4 7-5 Amendment 2, 225 E3-3