2CAN050702, License Amendment Requesting, Technical Specification 3.1.1.4, Moderator Temperature Coefficient

License Amendment Requesting, Technical Specification 3.1.1.4, Moderator Temperature Coefficient

ML071370312
Person / Time
Site:	Arkansas Nuclear
Issue date:	05/08/2007
From:	Mitchell T Entergy Operations
To:	Document Control Desk, NRC/NRR/ADRO
References
2CAN050702
Download: ML071370312 (10)

Text

iEt VWNEntergy-- Entergy Operations, Inc.

1448 S.R. 333 Russellville, AR 72802 Tel 479-858-3110 Timothy G. Mitchell Vice President, Operations Arkansas Nuclear One 2CAN050702 May 8, 2007 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555

SUBJECT:

License Amendment Request Technical Specification 3.1.1.4, Moderator Temperature Coefficient Arkansas Nuclear One, Unit 2 Docket No. 50-368 License No. NPF-6

Dear Sir or Madam:

Pursuant to 10 CFR 50.90, Entergy Operations, Inc. (Entergy) hereby requests the following amendment for Arkansas Nuclear One, Unit 2 (ANO-2). The proposed change will modify ANO-2 Technical Specification (TS) 3.1.1.4, Moderator Temperature Coefficient (MTC).

Specifically, the change will modify the surveillance frequency to be based on effective full power days instead of boron concentration.

The proposed change has been evaluated in accordance with 10 CFR 50.91 (a)(1) using criteria in 10 CFR 50.92(c) and it has been determined that this change involves no significant hazards consideration. The bases for these determinations are included in the attached submittal.

The proposed change does not include any new commitments. The proposed change is similar to the Waterford Steam Electric Station, Unit 3 TS and to NUREG-1432, Standard Technical Specifications, Combustion Engineering Plants.

Entergy requests approval of the proposed amendment by February 1, 2008. Once approved, the amendment shall be implemented within 60 days. Although this request is neither exigent nor emergency, your prompt review is requested.

2CAN050702 Page 2 of 2 If you have any questions or require additional information, please contact Dana Millar at 601-368-5445.

I declare under penalty of perjury that the foregoing is true and correct. Executed on May 8, 2007.

Sincerely,

• TGM/DM Attachments:

1. Analysis of Proposed Technical Specification Change

2. Proposed Technical Specification Changes (mark-up) cc: Dr. Bruce S. Mallett Regional Administrator U. S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011-8064 NRC Senior Resident Inspector Arkansas Nuclear One P. 0. Box 310 London, AR 72847 U. S. Nuclear Regulatory Commission Attn: Ms. Farideh E. Saba MS 0-8 B1 Washington, DC 20555-0001 Mr. Bernard R. Bevill Director Division of Radiation Control and Emergency Management Arkansas Department of Health & Human Services P.O. Box 1437 Slot H-30 Little Rock, AR 72203-1437

Attachment 1 2CAN050702 Analysis of Proposed Technical Specification Change to 2CAN050702 Page 1 of 4

1.0 DESCRIPTION

This letter is a request to amend Operating License NPF-6 for Arkansas Nuclear One, Unit 2 (ANO-2).

The proposed change will revise ANO-2 Technical Specification 3.1.1.4, Moderator Temperature Coefficient Surveillance Requirements (SR) 4.1.1.4.2 b and c. Specifically, the frequency at which the Moderator Temperature Coefficient (MTC) is determined will be revised to be based on effective full power days (EFPD) instead of boron concentration. The proposed change in frequency is similar to the frequency contained in NUREG-1432, Standard Technical Specifications, Combustion EngineeringPlants.

2.0 PROPOSED CHANGE

Technical Specification SR 4.1.1.4.2 b and c state:

The MTC shall be determined at the following frequencies and THERMAL POWER conditions during each fuel cycle:

b. At any THERMAL POWER, prior to reaching a RATED THERMAL POWER equilibrium boron concentration of 800 ppm.

c. At any THERMAL POWER, within 14 EFPD after reaching a RATED THERMAL POWER equilibrium boron concentration of 300 ppm. (Note 2)

The proposed change will modify the above as follows:

The MTC shall be determined at the following frequencies and THERMAL POWER conditions during each fuel cycle:

b. At greater than 5% of RATED THERMAL POWER, prior to reaching 40 effective full power days (EFPD) core burnup.

c. At greater than 5% of RATED THERMAL POWER, within 7 EFPD of reaching two-thirds of expected core burnup. (Note 2)

Upon approval, appropriate changes will be made to the associated TS bases.

In summary, the proposed SR change bases the test frequency on EFPD instead of boron concentration. The change provides clarification to the existing frequency.

3.0 BACKGROUND

The MTC relates a change in core reactivity to a change in reactor coolant temperature. A positive MTC means that reactivity increases with increasing moderator temperature; conversely, a negative MTC means that reactivity decreases with increasing moderator temperature. The reactor is designed to operate with a negative MTC over the largest possible range of fuel cycle operation. Therefore, a coolant temperature increase will cause a reactivity decrease, so that the coolant temperature tends to return toward its initial value.

Reactivity decrease that causes a coolant temperature increase will thus be self limiting, and stable power operation will result.

to 2CAN050702 Page 2 of 4 MTC values are predicted at selected times during the safety evaluation analysis and are confirmed to be acceptable by measurement. The intent of the SRs is to assure the MTC response is as predicted. The Reactor Coolant System (RCS) boron concentrations associated with the current SRs were included in the original ANO-2 TS. The fuel cycle length was 12 months at that time with a beginning of cycle (BOC) RCS boron concentration of approximately 1000 ppm. The 800 ppm RCS boron concentration corresponded to a BOC measurement of the MTC. The 300 ppm RCS boron concentration corresponded to reaching approximately two-thirds of the expected core burnup. When the cycle length was changed to 18 months, the 800 ppm RCS boron concentration still provided an MTC measurement early in the cycle and the 300 ppm RCS boron concentration still provided a middle of cycle measurement. The proposed change will continue to require MTC measurement at approximately the same intervals.

4.0 TECHNICAL ANALYSIS

The proposed change will associate the frequency for the two SRs with EFPD rather than RCS boron concentration. The change continues to provide assurance that the MTC is measured at specific intervals in the fuel cycle regardless of the fuel design (i.e., at the beginning and middle of the fuel cycle).

The measurement is performed at any RATED THERMAL POWER level greater than 5%

consistent with the TS applicability and NUREG-1432. The proposed change assures the original intent of the current SRs.

With the addition of Integral Fuel Burnable Absorbers (IFBAs) (i.e., zirconium diboride) fuel design, peak RCS boron concentration occurs later in the fuel cycle. As such, the proposed change is necessary to ensure the MTC measurement is performed at the appropriate intervals.

The nuclear design of the core ensures that the combined response of all reactivity coefficients in the power operating range to an increase in reactor thermal power yields a net decrease in reactivity.

5.0 REGULATORY ANALYSIS

5.1 Applicable Regulatory Requirements/Criteria The proposed changes have been evaluated to determine whether applicable regulations and requirements continue to be met.

According to General Design Criterion (GDC) 11 of Appendix A to 10 CFR Part 50, the reactor core and its interaction with the Reactor Coolant System (RCS) must be designed for inherently stable power operation, even in the possible event of an accident. In particular, the net reactivity feedback in the system must compensate for any unintended reactivity increases. The proposed change continues to satisfy this GDC.

to 2CAN050702 Page 3 of 4 In conclusion, Entergy has determined that the proposed change does not require any exemptions or relief from regulatory requirements, other than the TS, and does not affect conformance with any GDC differently than described in the Safety Analysis Report (SAR),

Section 3.1.2.

5.2 No Significant Hazards Consideration A change is proposed to the Arkansas Nuclear One, Unit 2 (ANO-2) Technical Specification Surveillance Requirements (SRs) associated with the moderator temperature coefficient (MTC). The SRs include the determination of MTC at specific Reactor Coolant System (RCS) boron concentrations associated with the beginning and middle of the cycle. The proposed change will replace the RCS boron concentrations with effective full power days (EFPD). The associated EFPDs are consistent with the beginning and middle of cycle test intervals currently associated with the RCS boron concentration.

Entergy Operations, Inc. has evaluated whether or not a significant hazards consideration is involved with the proposed amendment by focusing on the three standards set forth in 10 CFR 50.92, "Issuance of amendment," as discussed below:

1. Does the proposed change involve a significant increase in the probability or consequences of an accident previously evaluated?

Response: No.

The proposed change continues to perform the SRs to determine MTC at test intervals associated with the beginning and middle of the cycle. The results of the test will continue to verify that the predicted MTC is consistent with the measured.

Therefore, the proposed change does not involve a significant increase in the probability or consequences of an accident previously evaluated.

2. Does the proposed change create the possibility of a new or different kind of accident from any accident previously evaluated?

Response: No.

The proposed change does not result in any plant modifications or changes in the way the plant is operated. The revised SRs for confirming the MTC predicted values will continue to be performed at intervals associated with the beginning and middle of the cycle.

Therefore, the proposed change does not create the possibility of a new or different kind of accident from any previously evaluated.

to 2CAN050702 Page 4 of 4

3. Does the proposed change involve a significant reduction in a margin of safety?

Response: No.

The proposed change does not result in any changes to the test method or to the frequency of the test. The change of the test interval to use EFPD instead of RCS boron concentration still provides assurance that the predicted MTC is consistent with the measured.

Therefore, the proposed change does not involve a significant reduction in a margin of safety.

Based on the above, Entergy concludes that the proposed amendment presents no significant hazards consideration under the standards set forth in 10 CFR 50.92(c), and, accordingly, a finding of "no significant hazards consideration" is justified.

5.3 Environmental Considerations The proposed amendment does not involve (i) a significant hazards consideration, (ii) a significant change in the types or significant increase in the amounts of any effluent that may be released offsite, or (iii) a significant increase in individual or cumulative occupational radiation exposure. Accordingly, the proposed amendment meets the eligibility criterion for categorical exclusion set forth in 10 CFR 51.22(c)(9). Therefore, pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the proposed amendment.

Attachment 2 2CAN050702 Proposed Technical Specification Changes (mark-up)

V REACTIVITY CONTROL SYSTEMS MODERATOR TEMPERATURE COEFFICIENT LIMITING CONDITION FOR OPERATION 3.1.1.4 The moderator temperature coefficient (MTC) shall be within the limits specified in the CORE OPERATING LIMITS REPORT. The maximum upper design limit shall be:

a. Less positive than +0.5x10-4 Ak/k/°F whenever THERMAL POWER is <

70% of RATED THERMAL POWER, and

b. Less positive than 0.0 Ak/k/°F whenever THERMAL POWER is > 70% of RATED THERMAL POWER.

APPLICABILITY: MODES 1 and 2*#

ACTION:

With the moderator temperature coefficient outside any one of the above limits, be in at least HOT STANDBY within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.

SURVEILLANCE REQUIREMENTS 4.1.1.4.1 The MTC shall be determined to be within its limits by confirmatory measurements. MTC measured values shall be extrapolated and/or compensated to permit direct comparison with the above limits. (Note 1) 4.1.1.4.2 The MTC shall be determined at the following frequencies and THERMAL POWER conditions during each fuel cycle:

a. Prior to initial operation above 5% of RATED THERMAL POWER, after each fuel loading.(Note 1)

b. At greater than 5% of RATED THERMAL POWER, prior to reaching 40 effective full power days (EFPD) core burnup. At any THERMAL POWER, prior to reaching a RATED THERMAL POWER equilibrium boron concentration of 800 ppm.-

c. At greater than 5% of RATED THERMAL POWER, within 7 EFPD of reaching two-thirds of expected core burnup.At aniy THERMAL POWER, within 14 EFPD afte-r r*aching a RATED THEIRMAI POWER equilibrium boron concentration of 300 ppm. (Note 2)

• With Keff _Ž1.0.

1. See Special Test Exception 3.10.2.

Note 1: For fuel cycles that meet the applicability requirements given in WCAP-16011-P-A, the verification prior to entering MODE 1 may be made using the predicted MTC as adjusted for the measured boron concentration.

ARKANSAS - UNIT 2 3/4 1-5 Amendment No. 34,840,94,4,*167,236, 265,

4' Note 2: The MTC determination of surveillance 4.1.1.4.2.c is not required ifthe results of the tests required in surveillances 4.1.1.4.2.a and 4.1.1.4.2.b are within a tolerance of +/- 0.16 x 10-4 Ak/k/°F from the corresponding design values. For cycles that meet the applicability requirements given in WCAP-1 6011-P-A, the MTC determination of surveillance 4.1.1.4.2.c is not required if the result of the test required in surveillance 4.1.1.4.2.b is within a tolerance of +/- 0.16 x 10-4 Ak/k/°F from the corresponding design value.

ARKANSAS - UNIT 2 3/4 1-5 Amendment No. 34,80,84,94,467,2-W, 2-65,