ML040610679

Response to Third RAI Concerning the License Amendment to Increase Spent Fuel Pool Maximum Enrichment Limit with Soluble Boron Credit

ML040610679
Person / Time
Site:	Calvert Cliffs
Issue date:	02/25/2004
From:	Nietmann K Constellation Energy Group
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
Download: ML040610679 (5)

Text

!Z Kevin J. Nietmann 1650 Calvert Cliffs Parkway Plant General Manager Lusby, Maryland 20657 Calvert Cliffs Nuclear Power Plant 410 495-4101 Constellation Generation Group, LLC 410 495-4787 Fax Constellation Energy Group February 25, 2004 U. S. Nuclear Regulatory Commission Washington, DC 20555 ATTENTION: Document Control Desk

SUBJECT:

Calvert Cliffs Nuclear Power Plant Unit No. 1; Docket Nos. 50-317 Response to Third Request for Additional Information Concerning the License Amendment Request to Increase Unit I Spent Fuel Pool Maximum Enrichment Limit with Soluble Boron Credit

REFERENCES:

(a) Telephone Conference between Ms. D. J. Mitchell, et.al. (CCNPP) and Mr. G. S. Vissing, et.al. (NRC), on January 29, 2004, same subject (b) Letter from Mr. P. E. Katz (CCNPP) to Document Control Desk (NRC),

dated May 1, 2003, "License Amendment Request: Increase to the Unit I Spent Fuel Pool Maximum Enrichment Limit with Soluble Boron Credit" This letter provides the information requested in Reference (a). This information supports and/or clarifies the information provided in Reference (b). This information does not change the conclusions of the No Significant Hazards Consideration Determination or the Environmental Impact Review of Reference (b).

Attachment (1) contains the proposed words for the License Condition.

During the review of Reference (b), the Nuclear Regulatory Commission (NRC) staff determined that the current available data did not conclusively predict the maximum boron weight loss and that we would need to provide more data to accurately depict the boron loss trend. The NRC staff is concerned that, combined with this lack of data, key boron loss data may be overlooked during the longer intervals between coupon removal. During the conference call (Reference a), it was agreed to add a License Condition in Appendix C of the Technical Specifications that will require us to develop a coupon surveillance program for the Carborundum samples that wvill demonstrate the assumptions of conservative boron loss measurement. This proposed coupon surveillance program will be submitted to the NRC for the staff's approval no later than three years after the approval of our License Amendment Request to increase the Unit I Spent Fuel Pool maximum enrichment limit (Reference b). The three year period includes sufficient time to determine the modifications needed to the coupon surveillance program for the Carborundum samples to demonstrate the assumptions of a conservative boron loss measurement for 70 years. Since a possible modification to the coupon surveillance program includes using the Long-Term Surveillance Assembly (LTSA) samples as Accelerated Surveillance Assembly (ASA) samples, it is

Document Control Desk February 25, 2004 Page 2 requested that the LTSA coupon surveillance program be discontinued at this time so that sufficient coupons remain for possible extended ASA program.

We believe that a three year timeframe is acceptable for developing a surveillance program because any rack degradation over that period will not challenge the criticality calculation for the racks. Our criticality calculation provided in Reference (b) assumed a 26.25 percent boron loss. To determine if we will remain within this assumption for the next three years, we reviewed the coupon surveillance results (see table below). Based on these results we believe the projected weight loss over the three years needed to develop the revised coupon surveillance program for the Carborundum will be well with in the limit of operation. The next sample is scheduled to be withdrawn by October 2005 and the results from this sample will be used to verify the assumptions for the projected boron loss. If the results from this sample indicate that the 26.25 percent boron loss is approached, actions will be taken to ensure we remain in compliance.

Sample Packet Number Sample Type Time in Spent Fuel Weight Loss (%)

Pool 25 LTSA 4YR 4MO 1.67 26 LTSA lOYR 2MO 3.19 32 LTSA 17YR 2 MO 4.10 2 ASA 4YR 4M0 2.25 7 ASA 6YR 6MO 2.87 8+9* ASA 10YR 2MO 5.90 15 ASA 14 YR I MO 5.70

• - Sample Packet 8 consisted of four samples, IU, IL, 2U, and 2L. The percent change in weight of the four samples are 18.34, 3.85, 5.15, and 2.74. The average change in weight for the four samples is 7.52 percent; however, if IU is disregarded, the change is 3.91 percent, which is less than the Sample 9 results taken at the same time. It is believed that sample IU of Sample Packet 8 is an anomaly due to poor handling. Sample Packet 9 pulled at the same time had an average degradation of 4.28 percent. The average Sample 8 and 9 weight loss was 5.90 percent, as indicated above.

Employing a very conservative linear extrapolation based on the worst slope of degradation over time from the above results predicts that the ASA weight loss will be approximately 12.3 percent at the next ASA coupon extraction and 14 percent in three years.

12.31% = (5.90 - 2.87)/(44 months) * (96 months) + 5.70%

13.96% = (5.90 - 2.87)/(44 months) * (120 months) + 5.70%

Both are substantially less than the 26.25 percent boron loss assumed in the criticality calculation.

Therefore, we believe three years in an appropriate time frame to revise the coupon surveillance program.

Document Control Desk February 25, 2004 Page 3 Should you have questions regarding this matter, we will be pleased to iscuss them with you.

Ve y STATE OF MARYLAND

TO WIT:

COUNTY OF CALVERT 1,George Vanderheyden, being duly sworn, state that I am Vice President - Calvert Cliffs Nuclear Power Plant, Inc. (CCNPP), and that I am duly authorized to execute and file this License Amendment Request on behalf of CCNPP. To the best of my knowledge and belief, the statements contained in this document are true and correct. To the extent that these statements are not based on y personal knowledge, they are based upon information provided by other CCNPP employees an I nsultants. Such information has been reviewed in accordance with company practice and I belie it o e reliable.

Subscribed and sworn before me, a Notary Pubic in and for the State of Maryland and County of 5 this o29'y day of .y , 2004.

WITNESS my Hand and Notarial Seal: /,

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Notary Publi My Cornnission Expires: ,vcz 62S* 2oODa 7 Dat6 GV/DJM/bjd

Attachment:

(1) Additional License Condition cc: J. Petro, Esquire H. J. Miller, NRC J. E. Silberg, Esquire Resident Inspector, NRC R. J. Laufer, NRC R. 1.McLean, DNR G. S. Vissing, NRC

ATTACHMENT (1)

ADDITIONAL LICENSE CONDITION Calvert Cliffs Nuclear Power Plant, Inc.

February 25,2004

ATTACHMENT (1)

ADDITIONAL LICENSE CONDITION Amendment No. Additional Conditions Implementation Date This amendment requires the licensee 3 years after approval of this develop a long-term coupon surveillance amendment program for the Carborundum samples. This program must verify that the Carborundum degradation rates assumed in the licensee's analyses to prove subcriticality, as required by 10 CFR 50.68, remain valid over the seventy-year life span of the Unit I spent fuel pool. The licensee must submit this modified coupon surveillance program to the NRC under the 10 CFR 50.90 requirements for its review and approval.

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