NL-06-0756, E. I. Hatch Operating License Revision to Support Use of Potassium Iodide for an Interim Period, Supplemental Information

E. I. Hatch Operating License Revision to Support Use of Potassium Iodide for an Interim Period, Supplemental Information

ML061070078
Person / Time
Site:	Hatch
Issue date:	04/14/2006
From:	Sumner H Southern Nuclear Operating Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NL-06-0756
Download: ML061070078 (13)

Text

H. L Sumner, Jr. Southern Nuclear Vice President Operating Company, Inc.

Hatch Project Post Office Box 1295 Birmingham, Alabama 35201 April 14, 2006 SOUTHERN COMPANY A

Energy to Serve YourWorldsM Docket Nos.: 50-321 50-366 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555-0001 Edwin I. Hatch Nuclear Plant Operating License Revision to Support Use of Potassium Iodide for an Interim Period Supplemental Information Ladies and Gentlemen:

On March 17, 2006, Southern Nuclear Operating Company (SNC) submitted a request to revise the Edwin I. Hatch Nuclear Plant (HNP) Operating Licenses DPR-57 and NPF-5 to incorporate the use of potassium iodide (KI) into the HNP licensing basis for an interim period of approximately 4 years (reference letter NL-06-027 1 ).

This letter provides supplemental information requested by the NRC during an April 10, 2006 telephone conference. Enclosure 1 provides further information on the input parameters for the main control room radiological dose analysis incorporating KI for the loss-of-coolant accident (LOCA); specifically, excerpts of the applicable calculation are enclosed. Enclosure 2 contains an additional NRC commitment.

The 10 CFR 50.92 evaluation and the justification for the categorical exclusion from performing an environmental assessment that were included in the March 17, 2006 submittal continue to remain valid.

SNC continues to request approval of the proposed license amendments by May 15, 2006.

The proposed changes would be implemented within 30 days of issuance of the amendment.

(Affirmation and signature are on the following page.)

U. S. Nuclear Regulatory Commission NL-06-0756 Page 2 Mr. H. L. Sumner, Jr. states he is a Vice President of Southern Nuclear Operating Company, 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.

If you have any questions, please advise.

Respectfully submitted, SOUTHERN NUCLEAR OPERATING COMPANY H. L. Surnner, Jr. B N O f W m L K : STATE OF A U M k U AT WC6 M Y COMMISSION EXPIRES: NOV 38,20~i My commission expires: TBILU NOTMY ?UBL4C -wpIIBRs

Enclosures:

1. Input Parameters for the LOCA dose analysis incorporating KI

2. Additional Regulatory Commitment cc: Nuclear Operating Company Mr. J. T. Gasser, Executive Vice President Mr. D. R. Madison, General Manager - Plant Hatch RType: CHA02.004 U. S. Nuclear Regulatory Commission Dr. W. D. Travers, Regional Administrator Mr. C. Gratton, NRR Project Manager - Hatch Mr. D. S. Simpkins, Senior Resident Inspector - Hatch State of Georgia Mr. L. C. Barrett, Commissioner - Department of Natural Resources

Enclosure 1 Edwin I. Hatch Nuclear Plant Operating License Revision to Support Use of Potassium Iodide for an Interim Period Supplemental Information Input Parameters for the LOCA Dose Analysis Incorporating KI

Southern Nuclear Design Calculations Plant: Unlt: Calculation Number:

Edwin I. Hatch Nuclear Plant 1842 SMNH-06-001 Tltle: Sheet 3 LOCA Doses Using KI Figure 1. LocaDose Model for Containment Leakage Stack Release 2.18 cfm (2 2 rnin) b 1 Dummy (1.oo fl I m

I I MSlV Leakage I I

2.27 cfm u1 Environment Containment Control Room (2.60E5ft3) Inleakage (9.35E4 f13)

" t- 2.20 d m (< 2 rnin) 0.02 d m (2 2 min) 510 cfrn Note:

@ = LocaDose node number Filter with efficiency of 95% for all forms of iodine.

Stack release [Figure 21 and MSlV leakage [Figure 31 are modeled separately. These two flows are diverted to the Dummy node to properly deplete the activity in the containment.

Southern Nuclear Design Calculations 1 Plant: I Unit: I Calculatlon Number:

Edwin I. Hatch Nuclear Plant 11&2 I SMNH-06-001 Tltle: Sheet 4

[ LOCA Doses Using KI Figure 2. LocaDose Model for Stack Release Stack Release b

2.18 cfm ( 2 2 min)

Environment I

1 Containment Dummy (2.60E5 ft3) (1.00ft)

@ J ,Leakage 2.20 d m (< 2 min) 0.02 d m ( z 2 min)

Note:

@ = LocaDose node number Filter with efficiency of 95% for all forms of iodine.

Containment leakage [Figure I] and MSlV leakage [Figure 31 are modeled separately. These two flows are diverted to the Dummy node to properly deplete the activity in the containment.

Southern Nuclear Design Calculations Plant: Unit: Calculation Number:

Edwin I. Hatch Nuclear Plant 1&2 SMNH-06-001

Title:

Sheet 5

/ LOCA Doses Using KI Figure 3. LocaDose Model for MSlV Leakage Environment Condenser (1.oo ft3)

MSlV Leakage 510 cfm Note:

@ = LocaDose node number Filter with efficiency of 95% for all forms of iodine.

Previously calculated time-dependent activities within the condenser are based on an MSlV leakage rate of 2.27 cfrn from the containment. A high condenser exhaust rate is used to ensure that activities introduced into the condenser are immediately released to the environment.

Southern Nuclear Design Calculations 1 Plant: 1 Unit: 1 Calculation Number: I Edwin I. Hatch IVuclear Plant Il&2 1 SMNH-06-001 Tltle: Sheet 6 1 LOCA Doses Using KI Assumptions:

1. Reactor Power - The power level is 2818 MWt [Ref 3,4], which is 102% of the licensed thermal power of 2763 MW [Ref 6 and 7, Sec 15.3.3.4.2.11.

2. Core Fission Product Inventory -The equilibrium core inventory of fission products is as follows

[Ref 3 and 4, Table I]:

The dose contribution due to daughter products is not calculated and is assumed to be negligible

[Ref 3, Sheet 91.

3. Release from Core - In accordance with RG 1.3, 25% of the core iodine and 100% of the noble gases are assumed to be instantaneously released and uniformly distributed in the containment at the onset of the accident [Ref 1, Sheet 1.511.

4. Chemlcal Form - In accordance with RG 1.3, the species of iodine are assumed to be 91%

elemental, 4% organic, and 5% particulate [Ref 1, Sheet 1.3-11.

5. Contalnment Volume The volume of the containment is 2.6E5 f? [Ref 3, Sheet 51.

6. Contalnment Actlvlty Removal -Although drywell sprays are available, credit is for activity removal by sprays is set to zero.

7. Contalnment Leakage - The containment is assumed to leak at the peak pressure technical specification leak rate of 1.2% weight per day [Ref 8 and 9, Sec 5.5.121 or about 2.2 cfm [Ref 3, Sheet 51 for the duration of the accident.

8. Secondary Containment - It is assumed that the reactor building (secondary containment) draws down to negative pressure within 2 min of the start of the accident [Ref 8 and 9, SR 3.6.4.1.31. No holdup of activity in the secondary containment is credited. After drawdown, all the containment activity is released to the environment through the plant stack except for a bypass fraction of 0.9%

[Ref 9, SR 3.6.1.3.101; this is equivalent to a bypass flow rate is about 0.02 cfm, leaving 2.18 cfm for the stack [Ref 3, Sheet 51. The stack release is processed by SGTS filters. Based on a filter penetration of 2.5%, the Technical Specifications require the SGTS filters to have an efficiency of 97.5% [Ref 8 and 9, Sec 5.5.71. Applying a factor of two for conservatism, the efficiency is assumed to be 95% for all forms of iodine.

9. MSlV Leakage - It is assumed that the total MSlV leakage from all four main steam lines is 250 scfh

[Ref 4, Sheet 231. Polestar evaluation shows this to be equivalent to a containment leak rate of 2.33 cfm, based on a containment volume of 2.67E5 f? [Ref 51. The Polestar evaluation is based on a condenser volume of 83,180 ft3 and a leak rate of 3.95 cfm, consistent with the leak rate of 6.8%

per day in the GE EPU report [Ref 4, Sheet 231.

Southern Nuclear Design Calculations I plant: 1 Unit: 1 Calculation Number:

Edwin I. Hatch Nuclear Plant (1&2 ( SMNH-06-001

Title:

I Sheet 7 I LOCA Doses Using KI

10. Condenser Actlvlties - The activities in the condenser due to MSlV leakage as calculated by Polestar are shown in Table 2 [Ref 5, Table H-1). The table also shows the core inventory used to calculate the condenser activities.

11. MCR Volume -The MCR free volume is assumed to be 93,500 ft3[Ref 3, Sheet 6; Ref 4, Sheet 241.

12. MCR Ventilation - The design configuration of the emergency ventilation system is 400 cfm filtered intake, 0 cfm unfiltered intake, and 2100 cfm filtered recirculation [Ref 17, Case Ill. To balance the flows, the outleakage rate is set equal to filtered intake rate plus the inleakage rate.

13. MCR Fliter Efficiency Based on a filter penetration of 2.5%, the Technical Specifications require the intake and recirculationfilters to have an efficiency of 97.5% [Ref 8 and 9, Sec 5.5.71. Applying a factor of two for conservatism, the efficiency is assumed to be 950k for all forms of iodine.

14. Atmospheric Dispersion -The MCR atmospheric dispersion factors (x/Q values) are shown in Table 3 for Unit 1 [Ref 2, Sheet 81 and Unit 2 [Ref 3, Sheet 81. The EAB and LPZ X/Q values are shown in Table 4 [Ref 3, Sheet 81.

15. Breathing Rates -The breathing rate for persons offsite is assumed to be 3.47E-4 m3/sec for the first 8 hr, 1.75E-4 m3/secfrom 8 to 24 hr, and 2.32E-4 m3/secthereafter [Ref 1, Sheet 1.3-21. The breathing rate in the MCR is assumed to be at the maximum rate of 3.47E-4 m3/secfor the duration of the accident.

16. Occupancy Factors The occupancy factors for the MCR are 100O/0for the first 24 hr, 6O0lOfrom 24 to 96 hr, and 40% thereafter [Ref 16, Sheet 6.4-191.

17. Accldent Duration - MCR and LPZ doses are calculated assuming a release duration and exposure time of 30 days, consistent with RG 1.3 [Ref 11and Standard Review Plan 6.4 [Ref 161. The EAB dose is calculated for a period of 2 hr in accordance with 10 CFR 100.1 1 [Ref 151.

18. Dose Reduction Uslng KI It is postulated that KI is taken by the MCR operator within 2 hr after the onset of the accident. It is assumed that KI reduces the thyroid dose by a factor of 10 [Ref 18, App F, Sec 31 for the period from 2 hr to 30 days.

Southern Nuclear Design Calculations Plant: Unlt: Calculation Number:

Edwin I. Hatch Nuclear Plant 1&2 SMNH-06-001

Title:

Sheet 8 I

( LOCA Doses Using KI Table 2. Condenser Activities due to MSlV Leakage

Southern Nuclear Design Calculations Plant: Unit: Calculation Number:

Edwin I. Hatch Nuclear Plant 1&2 SMNH-06-001 Tltle: I Sheet 9

/ LOCA Doses Using KI Table 2. Condenser Activities due to MSlV Leakage (Continued)

Southern Nuclear Design Calculations Plant: Unit: Calculation Number:

Edwin I. Hatch Nuclear Plant 1 &2 SMNH-06-001

Title:

Sheet 10 1 LOCA Doses Usina KI I I Table 3. MCR Atmospheric Dispersion Factors Note: Unit Icontainment xIQ values are used for MSlV leakage and Unit 2 for containment leakage.

Table 4. Offsite Atmospheric Dispersion Factors

Enclosure 2 Edwin I. Hatch Nuclear Plant Operating License Revision to Support Use of Potassium Iodide for an Interim Period Supplemental Information Additional Regulatory Commitment

Enclosure 2 Edwin I. Hatch Nuclear Plant Operating License Revision to Support Use of Potassium Iodide for an Interim Period Supplemental Information Additional Regulatorv Commitment The following table identifies those actions committed by Southern Nuclear Operating Company (SNC) in this document for the Edwin I. Hatch Nuclear Plant. Any other statements in this submittal are provided for information purposes and are not considered to be regulatory commitments.

1 TYPE One-Time Continuing 1 SCHEDULED COMPLETION DATE COMMITMENT Action / compliance (If Required)

SNC will submit a license amendment request supporting full scope implementation of an alternative source term (AST) in accordance with the requirements of 10 CFR 50.90 and 10 CFR 50.67.