ML080420477
| ML080420477 | |
| Person / Time | |
|---|---|
| Site: | Watts Bar  |
| Issue date: | 02/07/2008 |
| From: | Brandon M Tennessee Valley Authority |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| Download: ML080420477 (5) | |
Text
February 7, 2008 10 CFR 50.55a U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555-0001 Gentlemen:
In the Matter of
)
Docket Nos. 50-390 Tennessee Valley Authority )
WATTS BAR NUCLEAR PLANT (WBN) UNIT 1 - AMERICAN SOCIETY OF MECHANICAL ENGINEERS (ASME) BOILER AND PRESSURE VESSEL CODE, SECTION XI - REACTOR PRESSURE VESSEL HEAD (RPVH) PENETRATION TUBE REMOTE INNER-DIAMETER TEMPER BEAD (IDTB) REPAIR - GENERIC REQUEST FOR RELIEF G-RR CORRECTION TO RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION (RAI)
By letter dated December 14, 2007, TVA provided the response to the request for additional information (RAI) from NRC dated November 6, 2007 on the subject generic request for relief. During NRCs review of the RAI response, NRC questioned the validity of a reference to WBN Updated Final Safety Analysis Report (UFSAR) section 5.7.2.9. This USFAR reference was made on page E1-3 of the December 14, 2007 submittal. TVA investigated the reference in the RAI and determined the correct USFAR section is 5.2.1.5.
TVA determined that section 5.7.2.9 is a valid section number from the WBN Technical Specification related to this subject; however, the reference is not a valid USFAR section. TVA regrets this error will use this as a lesson learned for improving submittal quality.
provides a corrected page E1-3.
As part of TVAs interaction with NRC on this issue, a clarification to TVAs commitment was also discussed regarding the regulatory process that
U.S. Nuclear Regulatory Commission Page 2 February 7, 2008 would be applied should post implementation changes to the commitment made in the RAI response be needed in the future. Since a post implementation change to this commitment would require a change to the UFSAR, the 10 CFR 50.59 process would be invoked. A discussion of this change process is also provided in Enclosure 1.
provides a clarifying revision to commitment originally made in the December 14, 2007 submittal.
If you have any questions, please contact me at (423) 365-1824.
Sincerely, Original signed by Michael K. Brandon Manager, Site Licensing and Industry Affairs Enclosures cc: See page 3
U.S. Nuclear Regulatory Commission Page 3 February 7, 2008 cc (Enclosures):
NRC Senior Resident Inspector U.S. Nuclear Regulatory Commission Watts Bar Nuclear Plant 1260 Nuclear Plant Road Spring City, TN 37381 ATTN: Margaret H. Chernoff, Senior Project Manager U.S. Nuclear Regulatory Commission Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation MS O-8 H4-A Washington, DC 20555-0001 U.S. Nuclear Regulatory Commission Region II Sam Nunn Atlanta Federal Center 61 Forsyth Street, SW, Suite 23T85 Atlanta, Georgia 30303-8931
ENCLOSURE 1 (Page 1 of 1)
WATTS BAR NUCLEAR PLANT (WBN) UNIT 1 - AMERICAN SOCIETY OF MECHANICAL ENGINEERS (ASME) BOILER AND PRESSURE VESSEL CODE, SECTION XI - REACTOR PRESSURE VESSEL HEAD (RPVH) PENETRATION TUBE REMOTE INNER-DIAMETER TEMPER BEAD (IDTB) REPAIR - GENERIC REQUEST FOR RELIEF G-RR CLARIFICATION TO RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION (RAI)
[THE FOLLOWING IS A REPLACMENT PAGE FOR PAGE E1-3 OF TVAs DECEMBER 14, 2007 SUBMITTAL (Adams accession number ML073480424). THE REVISED TEXT IS IN ITALICS.]
(b) Using the original analytical parameters (loading conditions, material properties, and service life), TVA is unable to demonstrate that the postulated flaw would be acceptable using the NRC-approved safety factors for SQN and WBN.
A supplemental elastic-plastic fracture mechanics evaluation has been performed using the Watts Bar Unit 1-specific upper shelf Charpy V-notch impact energy of 79.1 ft-lb and deleting the Turbine Roll test and 2458 psig Hydrostatic Test transients from analytical consideration.
- This supplemental evaluation demonstrates that if a safety factor of 1.5 is applied to primary stresses and 1.0 is applied to secondary stresses in a flaw stability/crack driving force analysis for the faulted condition, a repaired reactor vessel upper head CRDM nozzle would be acceptable for 3 years of operation.
- This supplemental evaluation demonstrates that if a safety factor of 1.5 is applied to primary stresses and 1.0 is applied to secondary stresses in a flaw stability/crack driving forces analysis for the faulted condition, a repaired reactor vessel upper head Thermocouple Column nozzle would be acceptable for 3 years of operation.
For both response (a) and (b), administrative controls will restrict the future use of the Turbine Roll Test and Hydrostatic Test transients following an IDTP repair to the CRDM and/or Thermocouple Column nozzles. To accomplish this, TVA will revise WBN Unit 1 UFSAR Section 5.2.1.5 and UFSAR Table 5.2-2 to prohibit the performance of either of these two tests. In addition, site procedure 1-SI-0-8 will be revised to reflect that any additional performances of these tests will exceed the maximum allowed by the plants licensing basis. This administrative control will be implemented only if an IDTP repair is made under the purview of this request for relief.
While TVA currently has no plans and does not anticipate the need to perform either of these tests over the remaining licensed life of the plant, if a need to perform one of these tests was created while an IDPT repair was in place, a change to the UFSAR and above referenced plant procedure would be required. Existing TVA procedures would require entry into the 10 CFR 50.59 process to evaluate this change and seek NRC review and approval, as appropriate.
ENCLOSURE 2 (Page 1 of 1)
COMMITMENT (revised)
- 1. As an administrative control, TVA will revise WBN Unit 1 UFSAR Section 5.2.1.5 and UFSAR Table 5.2-2 to prohibit the performance of a Turbine Roll Test or a Hydrostatic Test transient. In addition, site procedure 1-SI-0-8 will be revised to reflect that any additional performances of these tests will exceed the maximum allowed by the plants licensing basis. This administrative control will be implemented only if an IDTP repair is made under the purview of this request for relief.