ML050600450
| ML050600450 | |
| Person / Time | |
|---|---|
| Site: | Watts Bar  |
| Issue date: | 03/10/2005 |
| From: | Pickett D NRC/NRR/DLPM/LPD2 |
| To: | Singer K Tennessee Valley Authority |
| Pickett D, NRR/DLPM, 415-1364 | |
| References | |
| TAC MC0665 | |
| Download: ML050600450 (13) | |
Text
March 10, 2005 Mr. Karl W. Singer Chief Nuclear Officer and Executive Vice President Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, Tennessee 37402-2801
SUBJECT:
WATTS BAR NUCLEAR PLANT, UNIT 1 ISSUANCE OF AMENDMENT REGARDING MAIN STEAMLINE BREAK ACCIDENT LEAKAGE RATE (TAC NO. MC0665)
Dear Mr. Singer:
The Commission has issued the enclosed Amendment No. 56 to Facility Operating License No. NPF-90 for Watts Bar Nuclear Plant (WBN), Unit 1. This amendment is in response to your application dated September 8, 2003 (WBN-TS-03-14), as supplemented by letter dated September 11, 2003.
The amendment will revise the Updated Final Safety Analysis Report for WBN by modifying the design and licensing basis to increase the postulated primary-to-secondary leakage in the faulted steam generator following a main steamline break accident from 1 to 3 gallons per minute.
A copy of the safety evaluation is also enclosed. Notice of issuance will be included in the Commission's biweekly Federal Register notice.
Sincerely,
/RA/
Douglas V. Pickett, Senior Project Manager, Section 2 Project Directorate II Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket No. 50-390
Enclosures:
- 1. Amendment No. 56 to NPF-90
- 2. Safety Evaluation cc w/enclosures: See next page
March 10, 2005 Mr. Karl W. Singer Chief Nuclear Officer and Executive Vice President Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, Tennessee 37402-2801
SUBJECT:
WATTS BAR NUCLEAR PLANT, UNIT 1 ISSUANCE OF AMENDMENT REGARDING MAIN STEAMLINE BREAK ACCIDENT LEAKAGE RATE (TAC NO. MC0665)
Dear Mr. Singer:
The Commission has issued the enclosed Amendment No. 56 to Facility Operating License No. NPF-90 for Watts Bar Nuclear Plant (WBN), Unit 1. This amendment is in response to your application dated September 8, 2003 (WBN-TS-03-14), as supplemented by letter dated September 11, 2003.
The amendment will revise the Updated Final Safety Analysis Report for WBN by modifying the design and licensing basis to increase the postulated primary-to-secondary leakage in the faulted steam generator following a main steamline break accident from 1 to 3 gallons per minute.
A copy of the safety evaluation is also enclosed. Notice of issuance will be included in the Commission's biweekly Federal Register notice.
Sincerely,
/RA/
Douglas V. Pickett, Senior Project Manager, Section 2 Project Directorate II Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket No. 50-390
Enclosures:
- 1. Amendment No. 56 to NPF-90
- 2. Safety Evaluation cc w/enclosures: See next page DISTRIBUTION:
PUBLIC PDII-2 r/f DPickett BClayton MMarshall EHackett JHayes RDennig TBoyce GHill (2)
OGC ACRS DLPM Dpr SCahill, RII)
MS ACCESSION NO.: ML050600450 NRR-058 OFFICE PM:LPD2-2 LA:LPD2-2 SC:SPSB SC:IROB OGC SC:LPD2-2 NAME DPickett BClayton RDennig RTjader for TBoyce JHull MMarshall DATE 03 / 3 /05 03 / 3 /05 02 / 25 /05 03 / 10 /05 03 / 9 /05 03 / 10 /05 OFFICIAL RECORD COPY
Mr. Karl W. Singer Tennessee Valley Authority WATTS BAR NUCLEAR PLANT cc:
Mr. Ashok S. Bhatnagar, Senior Vice President Nuclear Operations Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. Larry S. Bryant, General Manager Nuclear Engineering Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. William R. Lagergren Site Vice President Watts Bar Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Spring City, TN 37381 General Counsel Tennessee Valley Authority ET 11A 400 West Summit Hill Drive Knoxville, TN 37902 Mr. John C. Fornicola, Manager Nuclear Assurance and Licensing Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. Fredrick C. Mashburn Senior Program Manager Nuclear Licensing Tennessee Valley Authority 4X Blue Ridge 1101 Market Street Chattanooga, TN 37402-2801 Mr. Paul L. Pace, Manager Licensing and Industry Affairs Watts Bar Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Spring City, TN 37381 Mr. Jay Laughlin, Plant Manager Watts Bar Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Spring City, TN 37381 Senior Resident Inspector Watts Bar Nuclear Plant U.S. Nuclear Regulatory Commission 1260 Nuclear Plant Road Spring City, TN 37381 County Executive Rhea County Courthouse 375 Church Street Suite 215 Dayton, TN 37321 County Mayor P. O. Box 156 Decatur, TN 37322 Mr. Lawrence E. Nanney, Director Division of Radiological Health Dept. of Environment & Conservation Third Floor, L and C Annex 401 Church Street Nashville, TN 37243-1532 Ms. Ann P. Harris 341 Swing Loop Road Rockwood, Tennessee 37854
TENNESSEE VALLEY AUTHORITY DOCKET NO. 50-390 WATTS BAR NUCLEAR PLANT, UNIT 1 AMENDMENT TO FACILITY OPERATING LICENSE Amendment No. 56 License No. NPF-90 1.
The Nuclear Regulatory Commission (the Commission) has found that:
A.
The application for amendment by Tennessee Valley Authority (the licensee) dated September 8, 2003, as supplemented by letter dated September 11, 2003, complies with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act), and the Commission's rules and regulations set forth in 10 CFR Chapter I; B.
The facility will operate in conformity with the application, the provisions of the Act, and the rules and regulations of the Commission; C.
There is reasonable assurance (i) that the activities authorized by this amendment can be conducted without endangering the health and safety of the public, and (ii) that such activities will be conducted in compliance with the Commission's regulations; D.
The issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public; and E.
The issuance of this amendment is in accordance with 10 CFR Part 51 of the Commission's regulations and all applicable requirements have been satisfied.
2 2.
Accordingly, the license is amended to authorize revision of the Updated Final Safety Analysis Report (UFSAR) as set forth in the application for amendment by the licensee dated September 8, 2003, and supplemented by letter dated September 11, 2003. The licensee shall update the UFSAR by modifying the design and licensing basis to increase the postulated primary-to-secondary leakage in the faulted steam generator following a main steamline break accident from one gallon per minute to three gallons per minute.
3.
This license amendment is effective as of the date of its issuance. Implementation of the amendment is the incorporation into the next UFSAR update made in accordance with 10 CFR 50.71(e), of the changes to the description of the facility as described in TVAs application dated September 8, 2003, as supplemented by letter dated September 11, 2003, and evaluated in the staffs Safety Evaluation attached to this amendment.
FOR THE NUCLEAR REGULATORY COMMISSION
/RA/
Michael L. Marshall, Jr., Chief, Section 2 Project Directorate II Division of Project Licensing Management Office of Nuclear Reactor Regulation Date of Issuance: March 10, 2005
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 56 TO FACILITY OPERATING LICENSE NO. NPF-90 TENNESSEE VALLEY AUTHORITY WATTS BAR NUCLEAR PLANT, UNIT 1 DOCKET NO. 50-390
1.0 INTRODUCTION
By letter dated September 8, 2003 (Agencywide Documents Access and Management Systems (ADAMS) Accession No. ML032550264), as supplemented by letter dated September 11, 2003 (ADAMS ML032590791), the Tennessee Valley Authority (TVA, the licensee), submitted a request for changes to the Watts Bar Nuclear Plant (WBN), Unit 1, Updated Final Safety Analysis Report (UFSAR). The requested changes would revise the UFSAR by modifying the design and licensing basis to increase the postulated primary-to-secondary leakage in the faulted steam generator following a main steamline break (MSLB) accident from 1 to 3 gallons per minute (gpm).
The supplemental letter dated September 11, 2003, revised the no significant hazards consideration included in the letter of September 8, 2003.
2.0 REGULATORY EVALUATION
Increasing the primary-to-secondary leakage in a faulted steam generator during a MSLB accident allows more steam generator tubes that exhibit axial oriented outside diameter stress corrosion cracking (ODSSC) at the tube support plate to remain in service. These affected tubes will be evaluated under the alternate repair criteria for axial ODSCC, as approved by the U.S. Nuclear Regulatory Commission (NRC) in License Amendment 38 issued on February 26, 2002 (ADAMS ML020590277), to determine if there is adequate structural and leakage integrity for the tubes to remain in service while maintaining the main control room and offsite radiological dose releases within the limits of Title 10 to the Code of Federal Regulations (10 CFR) Part 50, Appendix A, General Design Criterion (GDC) 19, Control room, and applicable fractions of the 10 CFR Part 100 dose limits as recommended by the guidance provided in NUREG-0800, Standard Review Plan (SRP).
TVAs request for the alternate repair criteria is consistent with Generic Letter (GL) 95-05, Voltage-Based Criteria for Westinghouse Steam Generator Tubes Affected by Outside Diameter Stress Corrosion Cracking, dated August 3, 1995. Item 2.b.4, Calculation of Offsite and Control Room Doses, of the GL states:
Reduction of reactor coolant iodine activity is an acceptable means for accepting higher projected leakage rates and still meeting the applicable limits of Title 10 of the Code of Federal Regulations Part 100 and GDC 19 utilizing licensing basis assumptions.
TVA has reduced the iodine activity level from 1.0 micro curies per gram (µCi/g) to 0.265 µCi/g by a request dated January 14, 2002 (ADAMS ML020170416). The NRC subsequently approved this request in License Amendment 41 dated November 18, 2002 (ADAMS ML023240361). Since the iodine activity of the reactor coolant system (RCS) has been lowered, a higher projected leakage rate (i.e., 1 gpm to 3 gpm) can be assumed.
3.0 TECHNICAL EVALUATION
=
Background===
As discussed above, Amendment 38, Steam Generator Alternate Repair Criteria for Axial ODSCC and Amendment 41, RCS Specific Activity Level, incorporated the consequences of a MSLB accident with an accident-induced primary-to-secondary leak rate of 1 gpm. TVAs letter dated September 8, 2003, proposed an increase to 3 gpm as the licensing basis value for primary-to-secondary leakage. The licensees letter indicated that no other changes were proposed to the assumptions or the methodology associated with the MSLB analysis.
Assessment of Radiological Consequences The licensee assessed the radiological dose consequences of a MSLB accident with a primary-to-secondary leak rate of 3 gpm. Doses were calculated for individuals assumed to be located at the exclusion area boundary (EAB), the low population zone (LPZ) and in the control room.
Doses were calculated for two cases. The first case assumed that the MSLB occurred following an iodine spike. This is referred to as the pre-existing spike case. For this case, the MSLB accident is assumed to occur with primary coolant activity at the Technical Specification (TS) value of 21 µCi/g of dose equivalent 131I. The second case, referred to as the accident-initiated spike case, assumes that the MSLB accident induces an iodine spike. At the time of the accident, primary coolant is assumed to occur at the TS value of 0.265 µCi/g of dose equivalent 131I. In both cases, the secondary coolant activity levels were assumed to be 0.1 µCi/g dose equivalent 131I. The licensees calculations showed that the consequences of a MSLB accident would not result in doses which would exceed the acceptance criteria in Appendix A of SRP 15.1.5, Radiological Consequences of Main Steam Line Failures Outside Containment of a PWR [Pressurized-Water Reactor], or GDC 19, Control Room.
Staff Assessment The staff performed calculations to confirm the conclusions reached by the licensee. The parameters which were utilized in the staff's assessment are presented in Table 1. The staff's calculations showed that the thyroid doses would be within the regulatory guidelines established in SRP 15.1.5 for individuals located at the EAB and LPZ. The staffs calculations also showed that the control room operator thyroid dose would be less than the limits of SRP 6.4 of NUREG-0800. The results of the staffs calculations are presented in Table 2.
The staff noted that the licensees calculations assumed a recirculation flow of 3600 cubic feet per minute (cfm). The recirculation flow should have been minimized to maximize the control room operators thyroid dose. The appropriate recirculation flow should have been 2960 cfm consistent with Technical Specification Surveillance Requirement 3.7.10.4. At this flow, the control room operators thyroid dose is maximized.
The staff also noted that the licensees analysis did not account for the fact that the in-place testing criteria for the control room emergency filtration HEPA filter and charcoal adsorber are 1 percent. Therefore, the effectiveness of the filter and the adsorber must be reduced to account for the 1 percent. With this reduction, the effective filtration and adsorption efficiencies are those which are presented in Table 1.
As noted in Table 1, the staffs calculations included the control room emergency ventilation systems recirculation flow at 2960 cfm and accounted for reduced efficiencies for the control rooms charcoal adsorber and HEPA filter. The staffs calculations confirmed that acceptable control room operator doses would be achieved with these changes to the analyses. All future licensee accident analyses need to account for a minimized control room emergency ventilation systems flow and reductions in charcoal adsorber and HEPA filter efficiencies when the in-place acceptance test criterion for these two components is greater than 0.05 percent. The latter are appropriate for all WBN engineered safety feature ventilation systems with an in-place acceptance criterion of greater than 0.05 percent.
4.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Tennessee State official was notified of the proposed issuance of the amendment. The State official had no comments.
5.0 ENVIRONMENTAL CONSIDERATION
The amendment changes requirements with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20. The NRC staff has determined that the amendment involves no significant increase in the amounts and no significant change in the types of any effluents that may be released offsite and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that the amendment involves no significant hazards consideration, and there has been no public comment on such finding
[68 FR 54745]. Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9). Pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendment.
6.0 CONCLUSION
The Commission has concluded, based on the considerations discussed above, that: (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.
Principal Contributor: J. Hayes Dated: March 10, 2005
TABLE 1 INPUT PARAMETERS FOR WATTS BAR UNIT 1 EVALUATION OF MSLB 1.
Primary coolant concentration @ 21 µCi/g of dose equivalent 131I.
Pre-existing Spike Value (µCi/g) 131I =
8.01 132I =
37.4 133I =
24.9 134I =
60.5 135I =
46.3 2.
Primary coolant concentration @ 0.265 µCi/g of dose equivalent 131I.
Pre-existing Spike Value (µCi/g) 131I =
0.101 132I =
0.472 133I =
0.315 134I =
0.764 135I =
0.584 3.
Mass of primary coolant and secondary coolant.
Mass of Primary Coolant (lb) 540,000 Mass of Secondary Coolant (lb) 348,000 4.
TS limits for DE 131I in the primary and secondary coolant.
Primary Coolant DE 131I concentration steady state (µCi/g) 0.265 Primary Coolant DE 131I concentration 48 hour5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> value (µCi/g) 21.0 Secondary Coolant DE 131I concentration (µCi/g) 0.1 5.
TS value for the primary to secondary leak rate.
Primary to secondary leak rate, any SG (gpd) 150 Primary to secondary leak rate, total all SGs (gpd) 600 6.
Maximum primary to secondary leak rate to the faulted and intact SGs.
Faulted SG (gpm) 3 Intact SGs (gpd/SG) 150 7.
Iodine partition factor Faulted SG 1
Intact SG 0.1 8.
Steam released to the environment Faulted SG (lbs) 150,000 (0 - 0.5 hr) 1,000 (0.5 - 8 hrs)
Intact SGs (lbs) 480,000 (0 - 2 hrs) 871,000 (2 - 8 hrs) 9.
Letdown flow rate (gpm) 124.4
- 10. Release rate for 0.265 µCi/g of dose equivalent 131I Ci/hr 131I =
3.2 132I =
49.7 133I =
12.2 134I =
170 135I =
32.7
- 11. Atmospheric dispersion factors EAB (0-2 hrs) 6.07 x 10-4 LPZ (0-2 hrs) 1.41 x 10-4 LPZ (2-8 hrs) 6.68 x 10-4 Control Room (0-2 hrs) 4.43 x 10-3 Control Room (2-8 hrs) 3.35 x 10-3
- 12. Control room Volume (ft3) 257,198 Normal Makeup Flow (cfm) 3,200 Emergency Makeup Flow (cfm) 711 Makeup Filter Efficiency (%)
94.05 Unfiltered Inleakage (cfm) 51 Recirculation Filter Flow Rate (cfm) 2,889 Recirculation Filter Efficiency (%)
69.3
TABLE 2 MAIN STEAMLINE BREAK THYROID DOSE FOR WATTS BAR UNIT 1 Pre-existing Spike EAB LPZ Control Room Calculated doses (rem) 4.7 2.4 6.9 Regulatory Guidelines (rem) 30 30 30 Accident Initiated Spike EAB LPZ Control Room Calculated doses (rem) 4.3 10.7 29.5 Regulatory Guidelines (rem) 30 30 30