ML19203A006

NRR E-mail Capture - Waterford 3 - Final Request for Additional Information (Rais) Re Relief Request WF3-RR-19-2: Alternate Repair of Degraded Drain Line of Chemical and Volume Control System

ML19203A006
Person / Time
Site:	Waterford
Issue date:	07/19/2019
From:	April Pulvirenti Plant Licensing Branch III
To:	Zamber M Entergy Nuclear Operations
References
Download: ML19203A006 (3)

Text

NRR-DRMAPEm Resource From: Pulvirenti, April Sent: Friday, July 19, 2019 5:36 PM To: Zamber, Maria Cc: Davis, Robert; Tsao, John; Buford, Angela; Wengert, Thomas; Singal, Balwant

Subject:

Waterford 3 - FINAL Request for Additional Information (RAIs) RE Relief Request WF3-RR-19-2: Alternate Repair of Degraded Drain Line of Chemical and Volume Control System

Maria, By letter dated July 18, 2019 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML19199A708), Entergy Operations, Inc. (Entergy or the licensee) requested relief from certain requirements of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code),Section XI, IWA-4000, at Waterford Steam Electric Station Unit 3 (Waterford 3). Pursuant to Title 10 of the Code of Federal Regulations (CFR) 50.55a(z)(2), Entergy submitted Alternative WF3-RR-19-2 proposing an alternate repair of the degraded weld in the drain line of the Chemical and Volume Control System (CVCS) on the basis that complying with ASME Code,Section XI, would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety.

To complete its review, the NRC staff requests the following additional information. This Request for Additional Information was discussed with Maria Zamber, Paul Wood, John Schrage, and others of your staff on July 19, 2019.

Thank you, April Dr. April L. Pulvirenti Project Manager, Waterford Unit 3 United States Nuclear Regulatory Commission Office of Nuclear Reactor Regulation 301-415-1390

1. Section 3, Applicable Code Requirement, of the proposed alternative does not discuss the fact that a flaw will remain inservice, which triggers certain provisions in the ASME Code,Section XI. The 2007 Edition through 2008 Addenda of the ASME Code,Section XI, IWA-4422, addresses defect evaluation and examination. In addition, IWC-3132.2 states that: A component containing relevant conditions is acceptable for continued service if the relevant conditions are corrected by a repair /replacement activity or by corrective measures to the extent necessary to meet the acceptance standards of Table IWC-3410-1. Please discuss if IWA-4422 and IWC-3132.2 should be applicable to the proposed relief request. If not, provide justification.

2. Detail 3 of the proposed alternative provides a drawing of the proposed weld overlay. (a) Provide dimensions of approximate thickness and longitudinal length of the weld overlay (Item No. 6 in the drawing). Specifically, provide the weld overlay thickness above the socket weld (Item No. 1 and the elbow (Item No. 3). (b) Provide thickness of socket weld branch connection (Item No. 1), elbow (item no. 3), and seal weld (item No, 5). (c) Provide the vertical length of the 1

socket fillet weld (Item No. 4). Approximate or estimated dimensions for these items is acceptable, if the as-built dimensions are not available.

3. Page 4 of 9, under heading Structural evaluation, states that the allowable through-wall flaw is 1.7 inches (41% of the pipe circumference). (a) Discuss either how the allowable flaw size is derived or submit the flaw evaluation. (b) The NRC staff assumes that vibration in the drain line will continue after the weld overlay installation and the existing flaw may continue to grow. As such, discuss, in a qualitative manner, the crack growth of the existing pipe between now and refueling outage 23.

4. Section 4, Reason for Request, states that the degradation mechanism is attributed to low cycle/high stress (vibration) fatigue. After the weld overlay is applied, the flaw may still grow based on vibration. (a) Discuss whether compensatory measures will be taken to reduce the vibration of the drain line to minimize crack growth. (b) Discuss the operational leakage limits in Technical Specifications for the drain line. (c) Discuss the leakage detection system(s) that can detect potential leakage of the overlaid drain line in case the weld overlay degrades, (d) Discuss whether the drain line is located inside or outside the containment.

5. Section 6, Duration of Proposed Alternative, provide the approximate scheduled start date for Refueling Outage 23.

6. Table 2 of the calculation in the relief request shows the following minimum required thickness for the weld overlay:

Loading Condition Minimum Required Thickness (inch)

Equation 3- Hoop Stress, Pressure 0.004 Equation 8- Sustained Load-Deadweight 0.008 Equation 9- Occasional Load - OBE, Seismic 0.013 Equation 10- Thermal Expansion 0.021 (a) The licensees analysis shows that the minimum required thickness for the weld overlay is 0.021 inches. The licensee did not calculate the minimum required thickness caused by mechanical vibration. Discuss why the minimum required thickness was not calculated based on mechanical vibration.

(b) The licensee states that the ASME Code,Section III, NC-3652.3 requires only Equation 10 or Equation 11 to be met, not both. The licensee did not calculate the minimum required thickness per Equation 11. If the minimum required thickness per Equation 11 is greater than Equation 10, it seems that the thickness calculated from Equation 11 should be used as the minimum required thickness. Discuss why the minimum required thickness was not calculated using Equation 11.

(c) During the plant normal operation, the drain line will experience stresses caused by pressure, deadweight, temperature, and occasional vibration. It seems that the minimum required thickness of the weld overlay should include the contribution of the required thickness from pressure, deadweight, thermal expansion and vibration.

Discuss whether the minimum weld overlay thickness should be 0.046 inches (0.004 + 0.008 + 0.013 + 0.021).

7. Code Case N-666-1, paragraph 5(c) states that: A system leakage test shall be performed in accordance with IWA-4540 The licensee did not take exception to this provision; therefore, the NRC staff assumes that the licensee will perform the system leakage test. However, the NRC staff is not clear how a system leakage test can be performed in accordance with IWA-4540 while the plant is online. Discuss how a system leakage test can be performed in accordance with IWA-4540.

2

Hearing Identifier: NRR_DRMA Email Number: 130 Mail Envelope Properties (BN6PR09MB224260E6D034A9C7BB5049DC8FCB0)

Subject:

Waterford 3 - FINAL Request for Additional Information (RAIs) RE Relief Request WF3-RR-19-2: Alternate Repair of Degraded Drain Line of Chemical and Volume Control System Sent Date: 7/19/2019 5:36:02 PM Received Date: 7/19/2019 5:36:00 PM From: Pulvirenti, April Created By: April.Pulvirenti@nrc.gov Recipients:

"Davis, Robert" <Robert.Davis@nrc.gov>

Tracking Status: None "Tsao, John" <John.Tsao@nrc.gov>

Tracking Status: None "Buford, Angela" <Angela.Buford@nrc.gov>

Tracking Status: None "Wengert, Thomas" <Thomas.Wengert@nrc.gov>

Tracking Status: None "Singal, Balwant" <Balwant.Singal@nrc.gov>

Tracking Status: None "Zamber, Maria" <mzamber@entergy.com>

Tracking Status: None Post Office: BN6PR09MB2242.namprd09.prod.outlook.com Files Size Date & Time MESSAGE 5980 7/19/2019 5:36:00 PM Options Priority: Standard Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date:

Recipients Received: