ML010320401

Request for Additional Information - Proposed Technical Specification Change No. 244

ML010320401
Person / Time
Site:	Vermont Yankee
Issue date:	02/02/2001
From:	Pulsifer R NRC/NRR/DLPM/LPD1
To:	Balduzzi M Vermont Yankee
Pulsifer R M, NRR/DLPM, 415-3016
References
TAC MB0763, TAC MB0764
Download: ML010320401 (5)

Text

February 2, 2001 Mr. Michael A. Balduzzi Vice President, Operations Vermont Yankee Nuclear Power Corporation 185 Old Ferry Road P.O. Box 7002 Brattleboro, VT 05302-7002

SUBJECT:

VERMONT YANKEE NUCLEAR POWER STATION - REQUEST FOR ADDITIONAL INFORMATION - PROPOSED TECHNICAL SPECIFICATION CHANGE NO. 244 (TAC NOS. MB0763 AND MB0764)

Dear Mr. Balduzzi:

On December 19, 2000, the Vermont Yankee Nuclear Power Corporation (VYNPC) submitted proposed change no. 244 to the Technical Specifications (TSs) for Vermont Yankee Nuclear Power Station (VY). Specifically, VYNPC proposed to change the pressure-temperature (P-T) limits in Section 3.6 of the VY TSs. In the letter of December 19, 2000, VYNPC also requested that the staff approve two exemptions to allow VYNPC to use ASME Code Cases N-588 and N-640 as part of its bases for generating the new P-T limit curves for the VY reactor pressure vessel and reactor coolant pressure boundary.

We reviewed your submittal of December 19, 2000, and had a conference call with members of your staff on January 18, 2001, and we have determined that additional information is necessary to complete the review of the licensing action request. The staff is submitting its requests in the form of a Request for Additional Information (RAI). The staffs RAI is enclosed.

To expedite the review process, the staff requests and VYNPC has agreed to provide a response to the RAI by February 20, 2001.

Sincerely,

/RA/

Robert M. Pulsifer, Project Manager, Section 2 Project Directorate I Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket No. 50-271

Enclosure:

Request For Additional Information cc w/encl: See next page

Vermont Yankee Nuclear Power Station cc:

Regional Administrator, Region I Ms. Deborah B. Katz U. S. Nuclear Regulatory Commission Box 83 475 Allendale Road Shelburne Falls, MA 01370 King of Prussia, PA 19406 Mr. Raymond N. McCandless Mr. David R. Lewis Vermont Department of Health Shaw, Pittman, Potts & Trowbridge Division of Occupational 2300 N Street, N.W. and Radiological Health Washington, DC 20037-1128 108 Cherry Street Burlington, VT 05402 Ms. Christine S. Salembier, Commissioner Vermont Department of Public Service Mr. Gautam Sen 112 State Street Licensing Manager Montpelier, VT 05620-2601 Vermont Yankee Nuclear Power Corporation Mr. Michael H. Dworkin, Chairman 185 Old Ferry Road Public Service Board P.O. Box 7002 State of Vermont Brattleboro, VT 05302-7002 112 State Street Montpelier, VT 05620-2701 Resident Inspector Vermont Yankee Nuclear Power Station Chairman, Board of Selectmen U. S. Nuclear Regulatory Commission Town of Vernon P.O. Box 176 P.O. Box 116 Vernon, VT 05354 Vernon, VT 05354-0116 Director, Massachusetts Emergency Mr. Richard E. McCullough Management Agency Operating Experience Coordinator ATTN: James Muckerheide Vermont Yankee Nuclear Power Station 400 Worcester Rd.

P.O. Box 157 Framingham, MA 01702-5399 Governor Hunt Road Vernon, VT 05354 Jonathan M. Block, Esq.

Main Street G. Dana Bisbee, Esq. P. O. Box 566 Deputy Attorney General Putney, VT 05346-0566 33 Capitol Street Concord, NH 03301-6937 Chief, Safety Unit Office of the Attorney General One Ashburton Place, 19th Floor Boston, MA 02108

ML010320401 No major changes were made.

OFFICE PDI-2/PM PDI-2/LA EMCB

• PDI-2/SC NAME RPulsifer TClark KWichman JClifford DATE 2/2/01 02/02/01 01/29/01 2/2/01

Request for Additional Information Proposed License Amendment to the Existing Pressure-Temperature Limits Vermont Yankee Nuclear Power Station Docket No. 50-271 The staff needs the following information to complete its review to ensure the new P-T curves conform to GDC 31 which requires in part that the reactor coolant pressure boundary be designed with sufficient margin and that this design reflects the effects of radiation on material properties.

P-T Limit Generation Methods

1. In Table 2 of Structural Integrity Associates (SIA) Assessment No. SIR-00-155, Rev. 0, you list the following Initial RTNDT values for the Vermont Yankee Nuclear Power Station (VYNPS) beltline materials:

Plate No. I-14: Initial RTNDT value of 30 EF Plate No. I-15: Initial RTNDT value of -10 EF Plate No. I-16: Initial RTNDT value of 0 EF Plate No. I-17: Initial RTNDT value of 0 EF Beltline Weld: Initial RTNDT value of 0 EF In contrast, both the NRCs Reactor Vessel Integrity Database and the Vermont Yankee Nuclear Power Corporation (VYNPC) submittal of September 24, 1993, list the Initial RTNDT values for these materials as:

Plate No. I-14: Initial RTNDT value of 40 EF Plate No. I-15: Initial RTNDT value of 30 EF Plate No. I-16: Initial RTNDT value of 30 EF Plate No. I-17: Initial RTNDT value of 30 EF Beltline Weld: Initial RTNDT value of -70 EF Provide your technical bases for changing the initial RTNDT data for the VY reactor pressure vessel (RPV) beltline materials, and reference any docketed documents (if any exist) that may support your bases for doing so.

2. In SIA Assessment No. SIR-00-155, Rev. 0, a limiting 1/4T ARTNDT value of 89 EF was used for P-T Limit Calculation Tables 6 and 8, and a limiting 3/4T ARTNDT value of 73 EF was used for P-T Limit Calculation Tables 5 and 7. Discuss your bases for selecting 89 EF and 73 EF as the conservative 1/4T and 3/4T ARTNDT values used for the generation of the P-T limit data in the Tables.

3. Appendix 5 to Welding Resource Council (WRC) Bulletin 175 provides an alternative basis for estimating the stress intensity factors for nozzles to pressure vessels. Provide the following plant-specific dimensional data relative to the design configuration documents for the N2 Recirculation and Feedwater nozzles to VYNPC RPV, as relative to the evaluation dimension criteria used in Appendix 5 of WRC Bulletin 175:

A. Thickness of the each nozzle in inches B. Assumed nozzle crack size a for each nozzle, in inches Enclosure

C. Apparent radius of the each nozzle (rn value) in inches D. Actual inner radius of each nozzle (ri value) in inches E. Nozzle corner radius (rc value) for each nozzle in inches F. RPV thickness and inner radius values, in inches, at the points were the nozzles are joined to the vessel.

4. Confirm that the neutron fluence levels for the feedwater nozzles and N2 recirculation nozzles are lower than the threshold value for neutron irradiation embrittlement of 1x1017 n/cm2 . If not, the effects of neutron irradiation embrittlement need to be accounted for in the ARTNDT assessments for the nozzle materials.

5. Provide the thermal stress intensity value and T value data, as a function of temperature, that were used to generate the P-T data for the limiting flange and nozzle materials assessed in SIA Assessment No. SIR-00-155, Rev. 0.

Neutron Fluence Data Questions

1. In your license amendment request, you are proposing to delete Figure 3.6.2, Fast Neutron Fluence (E>1 MeV) as a Function of Thermal Energy and Full Power Years, from the VY Technical Specifications (TS). However, the end-of-life neutron fluence value was derived from these curves and was based on Battelle Report BCL-585-84-3, dated May 15, 1984. Address the following questions in regard to how VY TS Fig. 3.6.2 and the Batelle report relate to the operation of the VYNPS.

A. At the time this figure was generated, how many full power years was the vessel exposed, and how were the values of the fast flux, which form the basis of Figure 3.6.2, estimated?

B. How many full power years of exposure does the vessel currently have?

C. When was a low leakage fuel management program implemented, and how long has the low leakage fuel management program been in effect? Answer both questions in terms of effective full power years (EFPY).

D. Since this figure was created, what efforts have been made to estimate (either computationally or experimentally) the fluence at the pressure vessel, and what are the results and how do they compare to the values given by in Figure 3.6.2?

What is the impact of the low leakage fuel management program on Figure 3.6.2?

Exemption Requests

1. The staff has not been able to determined that Code Case N-588 will provide VYNPC with any reduction in unnecessary burden benefit because the VY RPV is limited by the plate materials in upper intermediate shell, and not by one of the circumferential weld material in the vessel. Since application of Code Case N-588 does not appear to provide VY with any reduction in unnecessary burden benefit, the staff requests that VYNPC either withdraw the exemption request that would allow VYNPC to apply Code Case N-588 to the VY P-T limit calculations or that you provide additional information that demonstrates a reduction in unnecessary burden.