0CAN111405, Response to Request for Additional Information Request for Exemption from Holtec International Certificate of Compliance (CoC) (72-1014) Fuel Specification and Loading Conditions (TAC No. L24954)

Response to Request for Additional Information Request for Exemption from Holtec International Certificate of Compliance (CoC) (72-1014) Fuel Specification and Loading Conditions (TAC No. L24954)

ML14311A121
Person / Time
Site:	Arkansas Nuclear, Holtec
Issue date:	11/07/2014
From:	Pyle S Entergy Operations
To:	Document Control Desk, NRC/NMSS/SFPO
References
0CAN111405, TAC No. L24954
Download: ML14311A121 (6)

Text

Entergy Operations, Inc.

1448 S.R. 333 Russellville, AR 72802 Tel 479-858-4704 Stephenie L. Pyle Manager, Regulatory Assurance Arkansas Nuclear One 0CAN111405 November 7, 2014 ATTN: Document Control Desk Director, Spent Fuel Project Office Office of Nuclear Material Safety and Safeguards U.S. Nuclear Regulatory Commission Washington, DC 20555-0001

SUBJECT:

Response to Request for Additional Information Request for Exemption from Holtec International Certificate of Compliance (CoC) (72-1014) Fuel Specification and Loading Conditions (TAC No. L24954)

Arkansas Nuclear One - Units 1 and 2 Docket Nos. 50-313, 50-368, 72.13, and 72-1014 License Nos. DPR-51 and NPF-6

Dear Sir or Madam:

Pursuant to 10 CFR 72.7, Specific Exemptions, Entergy Operations (Entergy) requested an exemption from the requirements of 10 CFR 72.212(a)(2) and 10 CFR 72.212(b)(11) for Arkansas Nuclear One (ANO). The regulations require, in part, compliance to the terms and conditions of the Holtec International (Holtec) Certificate of Compliance (CoC) (72-1014).

Specifically, an exemption is requested from Appendix B, Section 2.1 of the Holtec CoC (72-1014), Fuel Specifications and Loading Conditions (Reference 1). Reference 1 was supplemented with an environmental report (Reference 2).

During review of the request, the NRC determined that additional information is needed to complete the technical review of the application. Reference 3 provides the NRCs request for that additional information. The purpose of this submittal is to provide the requested information. See the attached responses.

This letter contains no new commitments.

0CAN111405 Page 2 of 3 Should you have any questions concerning this submittal, please contact me.

Sincerely, ORIGINAL SIGNED BY STEPHENIE L. PYLE SLP/rwc

REFERENCES:

1. Entergy letter dated October 2, 2014, Request for Exemption from Holtec International Certificate of Compliance (CoC) (72-1014) Fuel Specification and Loading Conditions (0CAN101403)

(ML14279A246, ML14279A247)

2. Entergy letter dated October 14, 2014, Applicants Environmental Report Associated with the Request for Exemption from Holtec International Certificate of Compliance (CoC) (72-1014) Fuel Specification and Loading Conditions (TAC No. L24954)

(0CAN101406) (ML14289A239)

3. NRC Letter dated November 4, 2014, Request for Exemption from Holtec International Certificate of Compliance No. 1014 Fuel Specification and Loading Conditions at Arkansas Nuclear One Independent Spent Fuel Storage Installation - Request for Additional Information (TAC No. L24954) (ML14308A015)

Attachment:

Response to Request for Additional Information

0CAN111405 Page 3 of 3 cc: Mr. Marc L. Dapas Regional Administrator U. S. Nuclear Regulatory Commission Region IV 1600 East Lamar Boulevard Arlington, TX 76011-4511 NRC Senior Resident Inspector Arkansas Nuclear One P. O. Box 310 London, AR 72847 U. S. Nuclear Regulatory Commission Attn: Ms. Andrea E. George MS O-8B1 One White Flint North 11555 Rockville Pike Rockville, MD 20852 U. S. Nuclear Regulatory Commission Attn: Mr. William Allen MS 14A44 One White Flint North 11555 Rockville Pike Rockville, MD 20852

Attachment to 0CAN111405 Response to Request for Additional Information

Attachment to 0CAN111405 Page 1 of 2 Response to Request for Additional Information By letter dated October 2, 2014, as supplemented October 14, 2014, Entergy Operations, Inc. (Entergy) submitted a request for exemption from fuel specification and loading conditions in the Holtec International Certificate of Compliance No. 1014, Amendment No. 5, which is employed at their Arkansas Nuclear One Independent Spent Fuel Storage Installation.

Request for Additional Information

1. Identify the technical specifications or applicable Final Safety Analysis Report location where there is any specified limit on the MPC surface while it is located in the transfer cask (HI-TRAC).

Page 2 of Attachment 1 to ANO letter 0CAN101403 states that HI-TRAC/MPC annulus temperatures have remained steady at approximately 130°F to 135°F. This temperature monitoring may indicate the user needs to show compliance with an established limit. Therefore, the staff needs to make sure a thermal limit is not been exceeded for the MPC in this configuration.

This information is needed to assure compliance with 10 CFR 72.236(f).

Response

The fuel loading conditions of MPC-24-060 are as follows:

• Total Cask Heat Load = 15.384 kW

• Highest Fuel Bundle Heat Load = 0.823 kW

• Highest Assembly Average Burnup = 44,921.32 MWD/MTU The total MPC heat load and decay heat per storage location in the licensing basis thermal analysis presented in the HI-STORM 100 FSAR bounds the loading conditions specified above. Therefore, the fuel and component temperatures for MPC-24-060 will remain below the temperature limits specified in the FSAR. Although there is no temperature monitoring compliance limit for the as loaded MPC-24-060 conditions required by Amendment 5 of the Holtec Certificate of Compliance (CoC) (i.e., Technical Specifications) , the HI-TRAC/MPC annulus temperature was reported in the exemption request as additional information to show that the MPC was in a steady-state condition.

The HI-TRAC/MPC annulus temperature measurement of 130-135oF for MPC-24-060 does provide some additional insight. The thermal calculation reported in Table 4.5.4 of the FSAR shows that the annulus air temperature is between 455°F (MPC outer shell temperature) and 322°F (HI-TRAC inner shell inner surface). Therefore, the reported temperatures provide additional assurance that the peak clad temperature will remain below the allowable FSAR limit.

Attachment to 0CAN111405 Page 2 of 2

2. Clarify the statements None of the rectangular openings in the entire fuel basket are credited in the thermal analysis, so that the deposition of any fuel-related debris such as crud would be bounded. and A fuel pellet in contact with the baseplate would efficiently reject heat to the baseplate through conduction and would continue to be cooled by the thermosiphon natural convection flow through the mouseholes.

The first statement (see Section 2.2.3 of Holtec Report HI-2146265) seems to contradict Page 4.4.-4 of FSAR Section 4.4.1.1.ii.d which states the mouseholes are explicitly modeled, while the second statement (on same report) contradicts the first statement. In addition, the impact of one or more blocked mouseholes, either partially or completely, on the natural convection heat transfer capabilities of the MPC does not appear to have been analyzed in the FSAR. Therefore, since natural convection heat transfer was employed in the HI-STORM thermal model, it is difficult for staff to determine how the statements in the FSAR bound the current as-loaded configuration.

This information is needed to assure compliance with 10 CFR 72.236(f).

Response

The Staff is correct that the thermal model for normal storage conditions explicitly models the mouseholes. As described in Section 4.4.1.1 of the HI-STORM 100 FSAR, Revision 7, the flow area through the mouseholes is understated. For conservatism, only the area of the minimum semi-circular hole is credited in all the thermal models to evaluate normal, off-normal and accident conditions (i.e., the elongated rectangular portion of the hole is completely neglected). The results of the FSAR calculation conclude that the peak fuel cladding temperature is maintained, with the rectangular areas fully blocked. These modeling details are also described in Section 11.2.5 of the FSAR. Therefore, the statement in Holtec Report HI-2146265 None of the rectangular openings in the entire fuel basket are credited in the thermal analysis is appropriately supported by the FSAR. As stated in HI-2146265, the size of the rectangular openings is larger than the possible fuel pellets or cladding pieces; therefore, the current FSAR analyses assumption of partial blockage of MPC basket vent holes described in FSAR Section 11.2.5 bounds the current as-loaded configuration.