ML13338A696

2013/12/04 NRR E-mail Capture - Request for Additional Information (RAI) for Turkey Point Unit 3 Relief Request #13 (TAC MF2996)

ML13338A696
Person / Time
Site:	Turkey Point
Issue date:	12/04/2013
From:	Audrey Klett Plant Licensing Branch II
To:	Tomonto B Florida Power & Light Co
References
MF2996
Download: ML13338A696 (3)

Text

1 NRR-PMDAPEm Resource From: Klett, Audrey Sent: Wednesday, December 04, 2013 8:13 AM To: Tomonto, Bob (Bob.Tomonto@fpl.com); 'Hanek , Olga' (Olga.Hanek@fpl.com); 'Mihalakea, Stavroula' (Stavroula.Mihalakea@fpl.com)

Subject:

Request for Additional Information (RAI) for Turkey Point Unit 3 Relief Request #13 (TAC MF2996)Bob, Olga, Stavy, Background By application dated October 23, 2013 (Agencywide Documents Access and Management System Accession No. ML13318A010), Florida Power & Light Company (the licensee) requested relief from the American Society of Mechanical Engineers Boiler and Pressure Vessel Code for the alternate repair of degraded valve, 3-844A, in the common containment spray pump suction supply header. To complete its review, the Nuclear

Regulatory Commission (NRC) staff requests the follo wing additional information be provided by January 10, 2014. Request for Additional Information

1. The licensee's application dated October 23, 2013, contains a commitment, which states:

The projected final flaw size at time of repair is projected to be the present 5/16 inch [length] x 1/16 inch [width] measured. If the monthly measurement increases from the present by 1/16 inch in either direction (allowing 1/16 inch for measurement uncertainty), then the growth rate will be re-examined to verify the structural analysis conclusions and predicted growth rate.

(a) Page 4 of the application states that daily walkdowns will be performed to observe significant leakage. Provide the leak rate (in gallons per minute) that the licensee would consider significant. If the leakage does increase to the specified significant leak rate during service in the ensuing months, discuss the corrective actions.

(b) Clarify whether the licensee considers a length of 1/16 inches or 1/8 inches (1/16 inch + 1/16 inch for the measurement uncertainty) as the monthly measurement increase.

(c) If the monthly measurement indicates that the flaw grows more than the aforementioned length criterion, discuss whether any remedial actions will be taken, such as increasing the inspection frequency. If remedial actions will not be taken in this scenario, please justify why not.

(d) Discuss whether the physical location of the subject valve is conducive for the plant personnel to perform visual inspections during the daily walkdowns, measure the leakage, and to perform monthly measurements.

(e) Discuss whether the flaw on the valve is covered with insulation during normal operation. If yes, discuss whether the insulation will be removed for visual inspection during walkdowns.

2. Page 3 of the application states that the flaw size of 5/16 inches long and 1/16 inches wide was obtained based on the direct measurement at the outside surface of the bonnet. The length of the flaw at the inside surface of the bonnet may be longer than 5/16 inches. Discuss whether ultrasonic testing was conducted to measure the flaw size at the inside surface of the bonnet or bonnet thickness at the flaw location.

23. Page 4 of the application states that the subject valve will be repaired or replaced when the flaw length exceeds "the allowable and critical flaw size" of 5.63 inches and 23.4 inches in the circumferential and axial directions, respectively. Page 5 of the application refers the above sizes as "allowable critical size."

(a) Please clarify the "allowable and critical flaw size" and "allowable critical size" terminology. Please clarify whether the allowable flaw size is the same as the critical flaw size and whether the valve could fail catastrophically (or if it could become unstable and propagate uncontrollably) if the existing flaw reaches the critical flaw size. Explain whether the licensee will establish an allowable flaw size that is less than the critical flaw size to prevent such a catastrophic event so that actions can be taken before the flaw reaches its critical size.

(b) Justify why the allowable flaw size is the same as the critical flaw size.

(c) Discuss whether a crack growth rate criterion or a leak rate criterion should also be required to compliment the flaw size criterion as a defense-in-depth measure.

4. The corrosion report in the submittal concluded that the crack growth from corrosion for the subject valve is insignificant. The NRC staff notes that if a flaw can grow through the wall of the bonnet, then the crack growth rate must not be insignificant. Discuss why the flaw has been able to grow through the wall of the bonnet if the flaw growth from corrosion is insignificant.

5. Attachment 2 of the application contains a structural analysis performed by Structural Integrity Associates, Inc.. Page 4 of that analysis states that it used the following maximum operating conditions: a temperature of 205 degrees Fahrenheit (F) and a pressure of 180 pounds per square inch gauge (psig).

The structural report's piping isometrics drawing, 5613-P-599-3, indicated that the design temperature and pressure are 300 degrees F and 200 psig, respectively. Discuss why the design conditions were not used in the structural calculation.

Audrey Klett Project Manager NRR/DORL/LPLII-2

301-415-0489

Hearing Identifier: NRR_PMDA Email Number: 943 Mail Envelope Properties (Audrey.Klett@nrc.gov20131204081200)

Subject:

Request for Additional Information (RAI) for Turkey Point Unit 3 Relief Request #13 (TAC MF2996) Sent Date: 12/4/2013 8:12:51 AM Received Date: 12/4/2013 8:12:00 AM From: Klett, Audrey Created By: Audrey.Klett@nrc.gov Recipients: "Tomonto, Bob (Bob.Tomonto@fpl.com)" <Bob.Tomonto@fpl.com> Tracking Status: None

"'Hanek, Olga' (Olga.Hanek@fpl.com)" <Olga.Hanek@fpl.com> Tracking Status: None "'Mihalakea, Stavroula' (Stavroula.Mihalakea@fpl.com)" <Stavroula.Mihalakea@fpl.com> Tracking Status: None Post Office: Files Size Date & Time MESSAGE 5019 12/4/2013 8:12:00 AM

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