Text

License Amendment Request for Adoption of Technical Specifications Change for SR 3.6.4.1.3, Secondary Containment Drawdown Time
	ML15288A528
Person / Time
Site:	Hatch
Issue date:	10/15/2015
From:	Pierce C; Southern Co, Southern Nuclear Operating Co
To:	; Document Control Desk, Office of Nuclear Reactor Regulation
References
	NL-15-0012
	Download: ML15288A528 (25)
	v • d • e

Charles R. Pierce Southern Nuclear Regulatory Affairs Director Operating Company, Inc.

40 inverness Center Parkway Post Office Box 1295 Birmingham, AL 35242 Tel 205.992.7872 SOUTHE RN ..\

Fax 205.992.7601 NUCLEAR A SOUTHERN COMPANY OtT 1 5 2015 Docket Nos.: 50-321 NL-15-0012 50-366 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555-0001 Edwin I. Hatch Nuclear Plant - Units 1 and 2 License Amendment Request for Adoption of Technical Specifications Change for SR 3.6.4.1.3, Secondary Containment Drawdown Time Ladies and Gentlemen:

In accordance with the provisions of Title 10 of the Code of Federal Regulations

{1 0 CFR) Section 50.90, Southern Nuclear Operating Company (SNC) is submitting a request for an amendment to Edwin I. Hatch Nuclear Plant (HNP),

Unit 1 and 2 Technical Specifications {TSs) to revise Surveillance Requirement (SR) 3.6.4.1.3. The change would increase the allowable time for the Standby Gas Treatment System to draw down the secondary containment to negative pressure from 2 minutes to 10 minutes.

Enclosure 1 provides a description and assessment of the proposed changes, a regulatory analysis, and environmental considerations. Enclosure 2 provides a markup of the existing TS and Bases pages, and Enclosure 3 provides the clean typed revised TS pages.

SNC requests approval no later than November 1, 2016 and that, once approval is granted, the amendment be implemented within 60 days.

In accordance with 10 CFR 50.91 (b)(1), a copy of this application and the reasoned analysis about no significant hazards consideration is being provided to the designated Georgia official.

This letter contains no NRC commitments.

If you have any questions, please contact Ken McElroy at (205) 992-7369.

U.S. Nuclear Regulatory Commission NL-15-0012 Page2 Mr. C. R. Pierce states he is Regulatory Affairs Director of Southern Nuclear Operating and is authorized to execute this oath on behalf of Southern Nuclear Operating Company and to the best of his knowledge and belief, the facts set forth in this letter are true.

Respectfully submitted, c.R.f~

C. R. Pierce Regulatory Affairs Director Sworn to and subscribed before me this 1.5 ~day of 0e.)'oh.vt ,2015 My Commission expires: /6 ~ S- l bf 7 CRP/OCV

Enclosures:

1. Description and Assessment of the Proposed Changes

2. Markup Pages of Existing TS and TS Bases

3. Clean Typed TS Pages cc: Southern Nuclear Operating Company Mr. S. E. Kuczynski, Chairman, President & CEO Mr. D. G. Best, Executive Vice President & Chief Nuclear Officer Mr. D. R. Vineyard, Vice Presiden t- Hatch Mr. M.D. Meier, Vice Presiden t- Re gulatory Affairs Mr. D. R. Madison, Vice Presiden t- Fleet Operations Mr. B. J. Adams, Vice Presiden t- Engineering Mr. G. L. Johnson, Regulatory Affairs Manager.:. Hatch RTYPE: CHA02.004 U. S. Nuclear Regulatory Commission Mr. L. D. Wert, Regional Administrator (Acting)

Mr. R. E. Martin, NRR Senior Project Manager - Hatch Mr. D. H. Hardage, Senior Resident Inspecto r- Hatch

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Edwin I. Hatch Nuclear Plant- Units 1 and 2 License Amendment Request for Adoption of Technical Specifications Change for SR 3.6.4.1.3, Secondary Containment Drawdown Time Enclosure 1 Description and Assessment of the Proposed Changes to NL-15-0012 Description and Assessment of Proposed Change 1.0 Summary Description This evaiuation supports a request to amend Operating License DPR-57 and NPF-5 for Hatch Nuclear Plant {HNP) Units 1 and 2, respectively.

The amendment proposes to change Technical Specifications {TS)

Surveillance Requirement {SA) 3.6.4.1.3 for both units to allow the Standby Gas Treatment System {SGTS) to drawdown the secondary containment to ~ 0.20 inches of vacuum water gauge in 10 minutes, as opposed to the currently required 120 seconds. TS SA 3.6.4.1.4 requires that the SGTS maintain that vacuum for a period of one hour; no changes are proposed to this SR.

2.0 Detailed Description

2.1 System Description

The secondary containment at HNP consists of the Unit 1 Reactor Building {Zone 1), the Unit 2 Reactor Building {Zone 2), and the common Refueling Floor {Zone 3), as described in the Units 1 and 2 HNP Technical Requirements Manual {TRM) {Ref: 5.5).

The secondary containment boundary functions to contain, dilute, and hold up fission products that may leak from the primary containment into the secondary containment following a design basis accident {Ref. 5.6).

The secondary containment limits the ground level release of airborne radioactive materials and provides a means for the elevated release of the building atmosphere so that offsite doses from a fuel handling accident

{FHA) or Loss of Coolant Accident {LOCA) will be below the guidelines stated in 10 CFR 50.67. This is accomplished in conjunction with the SGTS.

The secondary containment boundary required to be Operable depends on the operating status of both units, as well as the configuration of doors, hatches, refueling floor plugs, and secondary containment isolation valves. For example, during a Unit 1 refueling outage, the Unit 1 Reactor Building may be open to the environment provided certain conditions are met. Some of those conditions are that all hatches separating the Refueling Floor and the Unit 1 Reactor Building be closed and sealed, and that at least one door in each access path separating the Refueling Floor from the Unit 1 Reactor Building be closed. This is known as the Type 'C' configuration in which Zone 2 and Zone 3 comprise the whole of the secondary containment. There are three other configurations, two of which have the Unit 2 Reactor Building open to the environment {'B1' and E1-1

Enclosure 1 to NL-15-0012 Description and Assessment of Proposed Change

'B2') and the third with all three zones closed and comprising the secondary containment ('A'). The HNP-1 and HNP-2 Technical Requirements Manuals (TAM) provide further details about each of the four secondary containment configurations (Ref 5.5).

The SGTS ensures that the radioactive m~terials leaking into the .

secondary containment following a design basis accident (DBA) are filtered and adsorbed prior to exhausting to the environment (Ref. 5.6).

To accomplish this, the SGTS automatically starts and operates in response to actuation signals indicative of a DBA. Any accident condition on either HNP-1 or HNP-2 results in the initiation of all the Unit 1 and Unit 2 SGTS trains. Following initiation, all charcoal filter trains start. Within 120 seconds, the SGTS has drawn down the secondary containment to a vacuum equal to 0.20 inches of water. The SGTS then maintains the secondary containment at this negative pressure, with respect to the outside environment, for the duration of the DBA. Both the 120 second drawdown time and the 0.20 inches of water vacuum are credited in the current HNP LOCA safety analysis. This amendment proposes to increase the drawdown time from 120 seconds to 10 minutes.

There are a total of four SGTS trains. The 1A and 1B trains are assigned to HNP-1, and the 2A and 28 trains are assigned to HNP-2.

Each single train has its own set of dampers, charcoal filter train, and controls. Each filter consists of a moisture separator, an electric heater, a pre-filter, a high efficiency particulate air (HEPA) filter, charcoal adsorbers, a second HEPA filter, an axial vane for HNP-1, and a centrifugal fan for HNP-2.

2.2 Current Licensing Basis For the purposes of this amendment, the dose consequences of increasing the secondary containment drawdown time are evaluated for the Main Control Room (MCR), the Technical Support Center (TSC), the Exclusion Area Boundary (EAB) and the Low Population Zone (LPZ).

HNP-1 and HNP-2 are currently licensed to 10 CFR 50.67, "Accident Source Term" (Refs 5.1 and 5.2). Accordingly, the regulatory limits are as follows:

1) 5 Rem Total Effective Dose Equivalent (TEDE) to the MCR,

2) 25 Rem TEDE to an individual located at any point on the EAB for a 2 hour2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months period following the onset of the postulated fission product release, and E1-2

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Enclosure 1 to NL-15-0012 Description and Assessment of Proposed Change

3) 25 Rem TEDE to an individual located on the outer boundary of the LPZ, who is exposed to the radioactive cloud resulting from the postulated release during the entire period of its passage.

For the TSC, the limits are based on NUREG 0737. As stated in the HNP Safety Evaluation Report (SEA) for the alternate source term per 10 CFR 50.67 (Ref. 5.2):

"The dose acceptance criteria in the TSC is accepted to be 5 rem TEDE for the duration of the accident to show consistency with NUREG-0737, "Clarification of TMI Action Plan requirements" and paragraph IV.E.B of Appendix E to 10 CFR Part 50".

2.3 Proposed Amendment This Technical Specifications amendment request proposes to revise the drawdown time requirement in SA 3.6.4.1.3, in LCO 3.6.4.1, "Secondary Containment", in both the HNP-1 and HNP-2 TS, from 120 seconds to ten minutes. The Bases will also be revised, as appropriate, per the Bases Control Program.

3.0 Technical Evaluation Among the four DBAs at HNP (Control Rod Drop Accident, LOCA, FHA, and Main Steam Line Break) the limiting accident with respect to drawdown time of the secondary containment is the LOCA (Ref. 5.4). The other DBAs do not credit holdup in the secondary containment and thus are not impacted by the change in the secondary containment drawdown time.

For example, there are two cases analyzed for the FHA. The first case assumes the secondary containment is drawn down within the current TS required time of 120 seconds, and the second case takes no credit for secondary containment holdup. Both cases are within the dose criteria, accordingly, there was no need to evaluate the FHA for the purposes of this amendment request (Ref. 5.4).

With respect to the Main Steam Line Break, two accidents were recognized for the initial licensing of HNP. One was the steam line break inside the secondary containment. The other was the steam line break outside of secondary containment. Both of them meet the regulatory dose criteria. The break outside the containment is the one considered as a Design Basis Accident (Ref. 5.4). Since the radiological consequences of the break outside the containment are more severe than those which result from the break inside containment, it was not necessary to consider the drawdown time with respect to the main steam line break for this amendment request.

Holding everything else constant, the TSC and off-site doses are most affected by an increase in the secondary containment drawdown time.

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Enclosure 1 to NL-15-0012 Description and Assessment of Proposed Change The HNP MCR is common to both units and is located in the turbine building (TB}. Consequently, dose to the control room operators depends on leakage into the turbine building and is not very sensitive to changes in the secondary containment drawdown time.

The off-site doses increase as a result of the increase in the drawdown time, but those doses are a small fraction of the regulatory limits, as presented later in this section.

Following this evaluation for increased drawdown time, the calculated TSC doses decreased due to in-leakage assumptions different than those in the previous calculation.

The dose results for the MCR, TSC; and off-site are presented in more detail in Paragraph 3.2.

The Alternative Source Term (AST} guidance of Regulatory Guide (RG}

1.183 was used to evaluate the radiological consequences of increasing the LOCA drawdown time.

The main leakage paths considered are:

Containment Leakage - This includes leakage of airborne activity in the drywell and the torus air space. Initially any leakage is assumed to be directly to the environment at ground level. After secondary containment drawdown to negative pressure, the leakage is assumed to be processed by the SGTS and released through the plant stack except for a small fraction that bypasses the SGTS.

Main Steam Isolation Valve (MSIV} Leakage - This leakage reaches the condenser via the steam lines. The condenser is then assumed to leak to the turbine building (TB} and eventually to the MCR and the environment.

Engineered Safety Features (ESF} Leakage -This occurs in the reactor building (RB} after the drywell sprays have been initiated and water from the torus is recirculated back into the drywell.

3.1 Assumptions Among the key assumptions for the LOCA analysis are (Ref. 5.3}:

Core activity is assumed to be released into the containment in two phases:

1} gap activity release which starts in 2 minutes and lasts 30 minutes, and E1-4

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2) early in-vessel release which starts at the conclusion of the gap activity release phase and lasts for 1.5 hours5.787037e-5 days 0.00139 hours 8.267196e-6 weeks 1.9025e-6 months .

It is assumed that the secondary containment draws down to the required negative pressure within 10 minutes of the start of the accident.

The primary containment (drywell and torus air) is assumed to leak at the peak pressure TS leak rate of 1.2% per day for the first 24 hr of the accident, reducing by 40% from 24 to 72 hr, and by 50% thereafter.

In modeling ESF leakage, it is conservatively assumed that all the iodine that is released to the containment is instantaneously transported to the torus water at the onset of the gap activity release phase.

It is assumed that the maximum leakage from all four main steam lines is 100 seth, with no limit on the leakage per line. It is postulated that the inboard MSIV on one of the four steam lines fails to close, thus creating an unrestricted flow path to the outboard MSIV.

Since the MCR is located within the TB, MCR doses are conservatively calculated assuming holdup in the TB, as this provides a direct in-leakage pathway from the TB to the MCR.

The design configuration of the MCR emergency ventilation system is 400 cfm filtered intake and 2100 cfm filtered recirculation. To allow for the potential need for less flow to pressurize the MCR, however, the filtered intake rate is assumed to be 250 cfm. Additionally, a MCR unfiltered in-leakage rate of 39 cfm is assumed (Ref. 5.8).

The filtered intake rate for the TSC ventilation system is 500 cfm and the filtered recirculation rate is 500 cfm. The unfiltered in-leakage rate is assumed to be 1000 cfm, which is double the intake rate. The outflow is assumed to be equal to intake rate of 500 cfm plus the in-leakage rate to balance the flows.

All releases from the TB are assumed to be at ground level through the RB vent plenum. The MCR dispersion values are applied to the TSC since the MCR values are bounding.

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Enclosure 1 to NL-15-0012 Description and Assessment of Proposed Change 3.2 Results This section presents the dose consequences determined from the evaluation of a 10 minute secondary containment drawdown time (Ref. 5.3).

The following table shows the impact on the MCR doses due to the increase in the drawdown time.

MCR Parameters Source 2 min RB Drawdown 10 min RB Drawdown MCR unfiltered in-leakage 115 39 rate (SCFM)

MCR Air 4.32 3.58 (Dose (Rem TEDE))

Ingress/Egress through TB 0.57 1.30 (Dose (Rem TEDE))

TB Air (Dose (Rem TEDE)) 0.0024 0.0059 Other External Shine 0.03 0.03 Sources (Dose (Rem TEDE))

Total Dose (Rem TEDE) 4.9 4.9 Regulatory Dose Limit 5 5 (Rem TEDE)

The activity in the TB results from MSIV leakage and is unaffected by the increase in the drawdown time. However, during the LOCA dose calculation process for this amendment, an error was discovered in the main condenser volume. As a result, it was necessary to reduce that volume for the LOCA dose calculation. This caused the activity concentrations in the condenser to increase. With the leakage rate from the condenser to the turbine building unchanged, the dose rates in the Turbine Building increased, accounting for the increase in the turbine building ingress and egress dose rates and in the control room dose due to Turbine Building shine (TB Air). Consequently, it was necessary to reduce the assumed MCR in-leakage rate (as shown on the Table) which primarily accounts for the decrease in the MCR dose from 4.32 to 3.58 Rem TEDE.

The MCR dose also decreased due to an adjustment to the finite cloud correction factor for determining the immersion dose. The correction factor is calculated to be 0.47, but was previously rounded up to 0.5. To gain margin, the revised calculation uses the value of 0.47 without rounding.

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to NL-15-0012 Description and Assessment of Proposed Change The net effect of these changes is that the MCR doses remain essentially unchanged from the 120 second draw down case.

The following table shows the impact of increasing the drawdown time on the off-site doses.

Offsite Dose (rem TEDE)

Exclusion Area Low Population Boundary Zone 2 min 10 min 2 min RB 10 min RB draw RB draw draw RB draw Pathway down down down down Ground 0.31 0.58 0.64 0.99 Elevated 0.03 0.03 0.11 0.11 Total 0.34 0.61 0.75 1.1 Regulatory 25 25 25 25 Limit With the increase in drawdown time, there is an increase in the ground level leakage duration, leading to greater off-site doses from this pathway. However, the doses remain small fractions of the regulatory limits.

The following table shows the impact of increasing the drawdown time on the TSC doses.

2 min RB 10 min RB Drawdown Drawdown TSC In-leakage 10,000 1,000 (cfm)

TSC Dose (rem 3.9 3.1 TEDE)

Regulatory Limit 5 5 (Rem TEDE)

As the TSC draws in outside air, the greater activity concentration in the environment leads to an increase in TSC dose. Previously, a very conservative high in-leakage rate was assumed for the TSC (1 0,000 cfm). In the revised analysis, a conservative, yet more reasonable, in-leakage rate is assumed (1 000 cfm), causing the calculated TSC dose to decrease.

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Enclosure 1 to NL-15-0012 Description and Assessment of Proposed Change The reduction in in-leakage to 1000 cfm is reasonable, as discussed below:

During normal operations, the Technical Support Center (TSC) HVAC system consists of an air handling unit with a condensing unit and an outside air inlet damper (X75-FOOS). During accident conditions, the outside air inlet damper will close, and the filter train air inlet damper will open, diverting the outside air through a filter train consisting of a pre-filter, an electric heater, a set of two HEPA filters, six charcoal adsorbers and a fan unit.

Except for the condensing unit, the TSC HVAC system is housed in a mechanical room. A surveillance procedure, performed once every two years, verifies that the TSC and the TSC mechanical room are at positive pressure with respect to the environment, and also verifies that the outside air supply to the TSC is within 500 cfm.

Unfiltered in-leakage can occur via the outside air damper (X75-F005) to the air handling unit if the damper's seal were to fail. However, an Engineering review of a failure of this damper determined that the maximum leakage past this damper would be 130 cfm, well within the 1000 cfm in-leakage assumption. Another surveillance procedure, also performed once every two years, verifies that the TSC filter train is capable of providing filtered air for the pressurization of the TSC. In addition it ensures that the outside air damper (X75-FOOS) is closed.

4.0 Regulatory Evaluation 4.1 Significant Hazards Consideration This Technical Specifications amendment seeks to increase the HNP-1 and HNP-2 secondary containment drawdown time, found in SR 3.6.4.1.3, from 120 seconds to 10 minutes.

Southern Nuclear Operating Company has evaluated whether or not a significant hazards consideration is involved with the proposed amendment by focusing on the three standards set forth in 10 CFR 50.92, "Issuance of Amendment," as discussed below:

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

Response: No This amendment proposes to increase the post-accident drawdown time for the secondary containment from its current value of 120 seconds, to 10 minutes. No physical modifications are proposed for any system, structure, or component (SSG) designed for the prevention of previously analyzed events. Neither does this amendment request change the operation or maintenance of any of those SSCs; accordingly the amendment does not involve a significant increase in the probability of occurrence of a previously evaluated event.

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Enclosure 1 to NL-15-0012 Description and Assessment of Proposed Change The increase in the drawdown time does not result in a significant increase in the consequences of a previously analyzed accident because the offsite doses, the main control room dose, and the technical support center dose do not significantly increase. As described in the Technical Evaluation section of this amendment request, the off-site doses for the Low Population Zone (LPZ) and the Exclusion Area Boundary (EAB) increase from 0.75 and 0.34 Rem TEDE to 1.10 and 0.61 Rem TEDE, respectively. However, this is still well within the 10 CFR 50.67 limits of 25 Rem for the LPZ and EAB.

Regarding the MCR, the increase in drawdown time has very little effect on dose to the MCR operators. Since the HNP MCR is located within the turbine building, MCR doses are due primarily to MSIV leakage which goes to the main condenser and subsequently leaks into the turbine building.

Finally, the dose to the TSC decreased from 3.9 Rem TEDE to 3.1 Rem TEDE. This is due to the reduction in the assumed unfiltered in-leakage to the TSC. Currently, 10,000 cfm is assumed for the TSC leakage. The new calculation assumed a more realistic value of 1000 cfm.

Therefore, the change in the drawdown time does not represent a significant increase in the consequences of a previously analyzed event.

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

Response: No This Technical Specifications revision request increases the allowed time given the SGTS to drawdown the secondary containment to 0.20 inches of water vacuum from 120 seconds to 10 minutes. No physical modifications are being made to the secondary containment system or to the SGTS as a result of this Tech Spec amendment request.

Additionally, other than the increase in the allowed drawdown time to 10 minutes, no changes are being made to the function or operation of the secondary containment. Therefore, its design function of containing fission products released after design basis accidents, such as LOCA, remains unchanged. Likewise, no changes are being proposed to the function or operation of the SGTS. It remains capable of adequately accomplishing its design function of processing the post accident atmosphere in the secondary containment. Since no new modes of operation are created, no new accident initiators are created by this amendment request.

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

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.. , - . ' l to NL-15-0012 Description and Assessment of Proposed Change Response: No Margins are applied at several levels with respect to the secondary containment safety function and to other functions intended to reduce off-site and on-site dose consequences.

One is the control room unfiltered in-leakage rate, which is reduced from 115 cfm to 39 cfm for this analysis. However, results for the last MCR in-leakage test were actually far below 39 cfm. In fact, the in-leakage rate tests for the pressurization mode of the Main Control Room Environmental Control system, performed in April of 2015, indicated rates between 8 and 12 scfm {Ref. 5. 7) , roughly one third of the assumed in-leakage value. Therefore, although the margin was reduced, a significant amount of margin remains.

In-leakage to the Technical Support Center was assumed at 1000 cfm for this calculation. Currently, 10,000 cfm is the assumed in-leakage.

Therefore margin is reduced with respect to this parameter. However, 10,000 cfm is an extremely high, unrealistic value. The 1000 cfm in-leakage assumed for this calculation is a reasonable and justifiable value, in fact equal to twice the filtered intake rate.

The MSIV leakage rate is assumed at the TS value of 100 scfh, unchanged from the current analysis.

As mentioned in the Technical Evaluation section of this submittal, the Volume Correction Factor {VCF) which is a parameter representing control room dose immersion, is assumed at 0.47 as opposed to the current evaluation which assumes a VCF of 0.50. The actual number is, in fact, 0.47, but was previously rounded up conservatively.

Therefore, this margin is being eliminated in the current calculation.

However, this does not represent a significant reduction in the margin of safety because margin exists in other areas, namely the Control Room in-leakage, TSC in-leakage, and Main Steam Isolation Valve leakage, as discussed above.

As described in the Technical Evaluation portion of this submittal, the margins to the 10 CFR 50.67 main control room and offsite dose limits are not significantly reduced. The total MCR doses are virtually unchanged. The off-site,doses do increase, but the resultant doses are still a small fraction{< 5%) of the regulatory limit of 25 Rem to the Low Population Zone and 25 Rem to the Exclusion Area Boundary.

The doses to the TSC actually decrease from those of the current analysis; the decrease is due to the reduced in-leakage assumption, as previously mentioned.

For all the reasons provided above, this amendment does not represent a significant reduction in a margin of safety.

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Enclosure 1 to NL-15-0012 Description and Assessment of Proposed Change 4.2 Applicable Regulatory Requirements 4.2.1 Appendix E to 10 CFR 50, "Emergency Planning and Preparedness for Production and Utilization Facilities"; Part IV, E.B.a. (i)

This section of the code states:

Adequate provisions shall be made and described for emergency facilities and equipment including:

... B.a. (i) A licensee technical support center and an emergency operations facility from which effective direction can be given and effective control can be exercised during an emergency; ...

Response

This proposed TS change deals in part with the HNP TSC, in that an increase in the secondary containment drawdown time will increase the dose to TSC personnel during a LOCA, however, no physical aspect of the TSC structure or support systems are affected by this TS amendment request.

Consequently, none of the equipment necessary for the Functionality of the TSC is affected by this TS change request.

All ventilation, filtration, dose projection and communications capabilities will remain the same following implementation of this TS amendment. Also, all TSC support equipment will continue to be operated, maintained, and surveilled as it was prior to the implementation of this change. Consequently, the HNP TSC will continue to meet the provisions of the Code following implementation of this TS amendment request.

4.2.2 NUREG 0737, "Clarification of TMI Action Plan Requirements" NUREG-0737 states:

The control room, technical support center (TSC), ... must be included among those areas where access is considered vital after an accident.

It also states:

The design dose rate for personnel in a vital area should be such that the guidelines of GDC 19 will not be exceeded during the course of the accident. GDC 19 requires that adequate radiation protection be provided such that the dose to personnel should not be in excess of 5 rem whole body, or its equivalent to any part of the body for the duration of the accident.

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Response

The dose acceptance criterion for the TSC is 5 Rem TEDE for the duration of the accident to show consistency with the dose limits of NUREG 0737. The dose to TSC personnel during the DBA LOCA will continue to be met following implementation of this TS amendment with a secondary containment drawdown time of 10 minutes.

4.2.3 10 CFR 50.67, "Accident Source Term" HNP is licensed to the alternate accident source term and has been since August of 2008, when the alternate accident source term SEA was issued by NRC. This submittal, which increases the drawdown time surveillance requirement for the HNP secondary containment is done under the provisions of the AST Regulation. The regulatory dose criteria in effect for the Main Control room, as well as those for offsite exposure, are consistent with the AST dose criteria of this Code, 10 CFR 50.67b(2)(i), (ii), and (iii).

4.2.4 Regulatory Guide 1.183, "Alternative Radiological Source Terms for Evaluating Design Bases Accid.ents at Nuclear Power Reactors", July 2000.

This Regulatory Guide (RG) provides guidance on acceptable applications of the alternative source term (AST) regulation, 10 CFR 50.67, including the scope and documentation of associated analyses, evaluations and the content of submittals.

Accordingly, the guidance of RG 1.183 is used to evaluate the radiological consequences of increasing the secondary containment drawdown time for the LOCA.

4.2.5 General Design Criteria 19, "Control Room" This GDC states, in part:

A control room shall be provided from which actions can be taken to operate the nuclear power unit safely under normal conditions and to maintain it in a safe condition under accident conditions, including LOCAs. Adequate radiation protection shall be provided to permit access and occupancy of the control room under accident conditions without personnel receiving radiation exposures in excess of 5 Rem whole body, or its equivalent to any part of the body, for the duration of the accident.

Response

A control room is provided in which appropriate controls and instrumentation are located to permit personnel to safely operate the unit under normal conditions or maintain it in a safe E1-12 to NL-15-0012 Description and Assessment of Proposed Change condition under accident conditions. The radiation protection permits the required habitability under both normal and accident conditions.

This proposed TS amendment increases the drawdown time of the secondary containment from 120 seconds to 10 minutes.

This has very little effect on the doses to control room operators since most of the control room exposure comes from MSIV leakage to the turbine building. Accordingly, following implementation of this amendment, a LOCA with the secondary containment being drawn down to the required negative pressure in 10 minutes will still result in the control room doses being below the regulatory limit which, under the 10 CFR 50.67 license, is 5 Rem TEDE.

4.2.6 General Design Criteria 41, "Containment Atmosphere Cleanup" This GDC states, in part:

Systems to control fission products, hydrogen, and other substances which may be released into the reactor containment shall be provided as necessary to reduce, consistent with the functioning of other associated systems, the concentration and quantity of fission products released to the environment following postulated accidents and to control the concentration of hydrogen or oxygen and other substances in the containment atmosphere following postulated accidents to assure that containment integrity is maintained.

Response

Fission products released into the reactor building following postulated accidents are automatically processed by the SGTS.

The SGTS initiation follows high-radiation signals from monitors in the refueling floor exhaust duct, from monitors in the reactor building exhaust duct, or from the primary containment isolation system signal.

This proposed amendment does not physically modify any aspect of the SGTS. The system will be operated and maintained as always. It is proposed to change TS SR 3.6.4.1.3 which requires that the SGTS drawdown the secondary containment in 2 minutes. This TS change requests a change to 10 minutes. The proposed 10 minute drawdown time does not prevent the SGTS from performing its design function as presented in GDC 41. Calculations and evaluations done for this TS change show that the SGTS will continue to adequately process the radioactive substances released into the secondary containment from a LOCA (Ref. 5.3). These evaluations confirm that doses to the control room operator, to E1-13 to NL-15-0012 Description and Assessment of Proposed Change Technical Support Center personnel, and to members of the public, will remain within federal radiation dose limits.

4.3 Environmental Consideration The proposed TS change would change a requirement with respect to installation or use of a facility component located within the restricted area, as defined in 10 CFR 50 Part 20, or would change an inspection or surveillance requirement. However, the proposed change does not involve (i) a significant hazards consideration, (ii) a significant change in the types or significant increase in the amounts of any effluents that may be released offsite, or (iii) a significant increase in individual or cumulative occupational radiation exposure. Accordingly, the proposed TS change meets the eligibility criterion for categorical exclusion set forth in 10 CFR 51.22(c)(9). Therefore, pursuant to 10 CFR 51.22(b), no environmentaf impact statement or environmental assessment need be prepared in connection with the proposed TS change.

5.0 References 5.1 Letter to NRC, NL-06-1637, "Edwin I. Hatch Nuclear Plant, Request to Implement an Alternative Source Term", August 29, 2006.

5.2 Letter to Plant E. I. Hatch, "Edwin I. Hatch Nuclear Plant, Unit Nos.

1 and 2, Issuance of Amendments Regarding Alternate Source Term (TAC Nos. MD2934 and MD2935), August 28,2008.

5.3 Calculation BH2-M-V999-0063, Version 8, "LOCA Doses using AST".

5.4 HNP-2 FSAR, Chapter 15, "Safety Analysis".

5.5 HNP 1 and HNP-2 Technical Requirements Manual, Section T8.1, "Secondary Containment Types".

5.6 HNP-1 and HNP-2 Technical Specifications Bases, Sections B 3.6.4.1 and B 3.6.4.3, "Secondary Containmenr and "Standby Gas Treatment System", respectively.

5.7 "Control Room Habitability Tracer Gas Leak Testing at Edwin I.

Hatch Nuclear Planf', RE203820434; April, 2015.

5.8 Plant Hatch procedure, "Control Room Habitability Program",

42EN-Z41-001-0.

E1-14

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Edwin I. Hatch Nuclear Plant- Units 1 and 2 License Amendment Request for Adoption of Technical Specifications Change for SR 3.6.4.1.3, Secondary Containment Drawdown Time Enclosure 2 Markup Pages of Existing TS and TS Bases

Secondary Containment 3.6.4.1 ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME C. (continued) C.2 Suspend CORE Immediately ALTERATIONS.

AND C.3 Initiate action to Immediately suspend OPDRVs.

SURVEILLANCE REQUIREMENTS SURVEIL~NCE FREQUENCY SR 3.6.4.1.1 Verify all secondary containment equipment In accordance with hatches are closed and sealed. the Surveillance Frequency Control Program SR 3.6.4.1.2 Verify one secondary containment access door in In accordance with each access opening is closed. the Surveillance Frequency Control Program SR 3.6.4.1.3 ,-------NOTE----------*-

The number of standby gas treatment (SGT) subsystem(s) required for this Surveillance is dependent on the secondary containment configuration, and shall be one less than the

.number required to meet LCO 3.6.4.3, "Standby Gas Treatment (SGT) System," for the given configuration.

Verify required SGT subsystem(s) will draw In accordance with down the secondary containment to ~ 0.20 inch the Surveillance of vacuum water gauge:_ji~ n<t!~~~~ri Frequency Control

..--------.1 Program 110 minutes t-----

(continued)

HATCH UNIT1 3.6-35 Amendment No. ~

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Secondary Containment 3.6.4.1 ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME C. (continued) C.2 Suspend CORE Immediately ALTERATIONS.

AND C.3 Initiate action to Immediately suspend OPDRVs.

SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.6.4.1.1 Verify all secondary containment equipment In accordance with hatches are closed and sealed. the Surveillance Frequency Control Program SR 3.6.4.1.2 Verify one secondary containment access door in In accordance with each access opening is closed. the Surveillance Frequency Control Program SR 3.6.4.1.3 ---------------NOTE --------------

The number of standby gas treatment (SGT) subsystem(s) required for this Surveillance is dependent on the secondary containment configuration, and shall be one less than the number required to meet LCO 3.6.4.3, "Standby Gas Treatment (SGT) System," for the given configuration.

Verify required SGT subsystem(s) will draw In accordance with down the secondary containment to ~ 0.20 inch the Surveillance of vacuum water gauge in sJ1 20 seoondsl. Frequency Control

~~1-0-m-in-u-te-s----~~--------- Program (continued)

HATCH UNIT 2 3.6-34 Amendment No. ~

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Secondary Containment B 3.6.4.1 BASES ACTIONS C.1. C.2. and C.3 (continued) case, inability to suspend movement of irradiated fuel assemblies would not be a sufficient reason to require a reactor shutdown.

SURVEILLANCE SR 3.6.4.1.1 and SR 3.6.4.1.2 REQUIREMENTS Verifying that secondary containment equipment hatches and one access door in each access opening are closed ensures that the infiltration of outside air of such a magnitude as to prevent maintaining the desired negative pressure does not occur. Verifying that all such openings are closed provides adequate assurance that exfiltration from the secondary containment will not occur. SR 3.6.4.1.1 also requires equipment hatches to be sealed. In this application, the term "sealed has no connotation of leak tightness. Maintaining secondary containment OPERABILITY requires verifying one door in the access opening is closed. An access opening contains one inner and one outer door. The intent is not to breach the secondary containment at any time when secondary containment is required. This is achieved by maintaining the inner or outer portion of the barrier closed at all times. However, all secondary containment access doors are normally kept closed, except when the access opening is being used for entry and exit or when maintenance is being performed on an access opening. When the secondary containment configuration excludes Zone I and/or Zone II, these SRs also include verifying the hatches and doors separating the common refueling floor zone from the reactor building(s). The Surveillance Frequency is controlled under the Surveillance Frequency Control Program.

SR 3.6.4.1.3 and SR 3.6.4.1.4 The Unit 1 and Unit 2 SGT Systems exhaust the secondary containment atmosphere to the environment through appropriate treatment equipment. To ensure that all fission products are treated, SR 3.6.4.1.3 verifies that the appropriate SGT System(s) will rapidly establish and maintain a negative pressure in the secondary containment. This is confirmed by demonstrating that the required SGT subsystem(s) will draw down the seconds containment to 10 minute ::: 0.20 inch of vacuum water gauge in s (13 seconds of

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el~e~ne~rator startup and breaker sing time is included in the t drawdown time). Thi nnot be accomplished if the secondary containment bound is not intact. SR 3.6.4.1.4 10 minutes (continued)

HATCH UNIT1 B 3.6-79 !REVISION 701

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Secondary Containment B 3.6.4.1 BASES ACTIONS C.1 C.21 and C.3 (continued)

I inability to suspend movement of irradiated fuel assemblies would not be a sufficient reason to require a reactor shutdown.

SURVEILLANCE SR 3.6.4.1.1 and SR 3.6.4.1.2 REQUIREMENTS Verifying that secondary containment equipment hatches and one access door in each access opening are closed ensures that the infiltration of outside air of such a magnitude as to prevent maintaining the desired negative pressure does not occur. Verifying that all such openings are closed provides adequate assurance that exfiltration from the secondary containment will not occur. SR 3.6.4~ 1 1 also I requires equipment hatches to be sealed. In this application, the term "sealed" has no connotation of leak tightness. Maintaining secondary containment OPERABILITY requires verifying one door in the access opening is closed. An access opening contains one inner and one outer door. The intent is not to breach the secondary containment at any time when secondary containment is required. This is achieved by maintaining the inner or outer portion of the barrier closed at all times. However, all secondary containment access doors are normally kept closed, except when the access opening is being used for entry and exit or when maintenance is being performed on an access opening. When the secondary containment configuration excludes Zone I and/or Zone II, these SRs also include verifying the hatches and doors separating the common refueling floor zone from the reactor building(s). The Surveillance Frequency is controlled under the Surveillance Frequency Control Program.

SR 3.6.4.1.3 and SR 3.6.4.1.4 The Unit 1 and Unit 2 SGT Systems exhausts the secondary containment atmosphere to the environment through appropriate treatment equipment. To ensure that all fission products are treated, SR 3.6.4.1.3 verifies that the appropriate SGT System(s) will rapidly establish and maintain a negative pressure in the secondary containment. This is confirmed by demonstrating that the required SGT subsystem(s) will draw down the seconda containment to 10 minute ::!: 0.20 inch of vacuum water gauge in ( 13 seconds of

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n~erator startup and brea c sing time is included in the drawdown tim is cannot be accomplished if the secondary contain me undary is not intact. SR 3.6.4.1.4 demonstrates t e required SGT subsystem(s) can 10 minutes (continued)

HATCH UNIT2 B 3.6-80 IReVISIO~l 791 f' * * * * ' ... ~, , f ,., .,.

Edwin I. Hatch Nuclear Plant - Units 1 and 2 License Amendment Request for Adoption of Technical Specifications Change for SR 3.6.4.1.3, Secondary Containment Drawdown Time Enclosure 3 Clean Typed TS Pages

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Secondary Containment 3.6.4.1 ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME C. (continued) C.2 Suspend CORE Immediately ALTERATIONS.

AND C.3 Initiate action to Immediately suspend OPDRVs.

SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.6.4.1.1 Verify all secondary containment equipment In accordance with hatches are closed and sealed. the Surveillance Frequency Control Program SR 3.6.4.1.2 Verify one secondary containment access door in In accordance with each access opening is closed. the Surveillance Frequency Control Program SR 3.6.4.1.3 ----------- ----NOTE --------*-- ----

The number of standby gas treatment (SGT) subsystem(s) required for this Surveillance is dependent on the secondary containment configuration, and shall be one less than the number required to meet LCO 3.6.4.3, "Standby Gas Treatment (SGT) System," for the given configuration.

Verify required SGT subsystem(s) will draw In accordance with down the secondary containment to ~ 0.20 inch the Surveillance of vacuum water gauge in s 10 minutes. Frequency Control Program (continued)

HATCH UNIT 1 3.6-35 Amendment No.

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Secondary Containment 3.6.4.1 ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME C. (continued) C.2 Suspend CORE Immediately ALTERATIONS.

AND C.3 Initiate action to Immediately suspend OPDRVs.

SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.6.4.1.1 Verify all secondary containment equipment In accordance with hatches are closed and sealed. the Surveillance Frequency Control Program SR 3.6.4.1.2 Verify one secondary containment access door in In accordance with each access opening is closed. the Surveillance Frequency Control Program SR 3.6.4.1.3 ---------- -----NOT E----*----- -----

The number of standby gas treatment (SGT) subsystem(s) required for this Surveillance is dependent on the secondary containment configuration, and shall be one less than the number required to meet LCO 3.6.4.3, "Standby Gas Treatment (SGT) System," for the given configuration.

Verify required SGT subsystem(s) will draw In accordance with down the secondary containment to <:: 0.20 inch the Surveillance of vacuum water gauge in s 10 minutes. Frequency Control Program (continued)

HATCH UNIT2 3.6-34 Amendment No.

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Charles R. Pierce Southern Nuclear Regulatory Affairs Director Operating Company, Inc.

40 inverness Center Parkway Post Office Box 1295 Birmingham, AL 35242 Tel 205.992.7872 SOUTHE RN ..\

Fax 205.992.7601 NUCLEAR A SOUTHERN COMPANY OtT 1 5 2015 Docket Nos.: 50-321 NL-15-0012 50-366 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555-0001 Edwin I. Hatch Nuclear Plant - Units 1 and 2 License Amendment Request for Adoption of Technical Specifications Change for SR 3.6.4.1.3, Secondary Containment Drawdown Time Ladies and Gentlemen:

In accordance with the provisions of Title 10 of the Code of Federal Regulations

{1 0 CFR) Section 50.90, Southern Nuclear Operating Company (SNC) is submitting a request for an amendment to Edwin I. Hatch Nuclear Plant (HNP),

Unit 1 and 2 Technical Specifications {TSs) to revise Surveillance Requirement (SR) 3.6.4.1.3. The change would increase the allowable time for the Standby Gas Treatment System to draw down the secondary containment to negative pressure from 2 minutes to 10 minutes.

Enclosure 1 provides a description and assessment of the proposed changes, a regulatory analysis, and environmental considerations. Enclosure 2 provides a markup of the existing TS and Bases pages, and Enclosure 3 provides the clean typed revised TS pages.

SNC requests approval no later than November 1, 2016 and that, once approval is granted, the amendment be implemented within 60 days.

In accordance with 10 CFR 50.91 (b)(1), a copy of this application and the reasoned analysis about no significant hazards consideration is being provided to the designated Georgia official.

This letter contains no NRC commitments.

If you have any questions, please contact Ken McElroy at (205) 992-7369.

U.S. Nuclear Regulatory Commission NL-15-0012 Page2 Mr. C. R. Pierce states he is Regulatory Affairs Director of Southern Nuclear Operating and is authorized to execute this oath on behalf of Southern Nuclear Operating Company and to the best of his knowledge and belief, the facts set forth in this letter are true.

Respectfully submitted, c.R.f~

C. R. Pierce Regulatory Affairs Director Sworn to and subscribed before me this 1.5 ~day of 0e.)'oh.vt ,2015 My Commission expires: /6 ~ S- l bf 7 CRP/OCV

Enclosures:

1. Description and Assessment of the Proposed Changes

2. Markup Pages of Existing TS and TS Bases

3. Clean Typed TS Pages cc: Southern Nuclear Operating Company Mr. S. E. Kuczynski, Chairman, President & CEO Mr. D. G. Best, Executive Vice President & Chief Nuclear Officer Mr. D. R. Vineyard, Vice Presiden t- Hatch Mr. M.D. Meier, Vice Presiden t- Re gulatory Affairs Mr. D. R. Madison, Vice Presiden t- Fleet Operations Mr. B. J. Adams, Vice Presiden t- Engineering Mr. G. L. Johnson, Regulatory Affairs Manager.:. Hatch RTYPE: CHA02.004 U. S. Nuclear Regulatory Commission Mr. L. D. Wert, Regional Administrator (Acting)

Mr. R. E. Martin, NRR Senior Project Manager - Hatch Mr. D. H. Hardage, Senior Resident Inspecto r- Hatch

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