ML16231A106

NRR E-mail Capture - Request for Additional Information - License Amendment Request to Revise Technical Specification 3.4.12

ML16231A106
Person / Time
Site:	Diablo Canyon
Issue date:	08/18/2016
From:	Balwant Singal Plant Licensing Branch IV
To:	Richardson M Pacific Gas & Electric Co
References
MF7501, MF7502
Download: ML16231A106 (4)

Text

NRR-PMDAPEm Resource From: Singal, Balwant Sent: Thursday, August 18, 2016 8:29 AM To: Richardson, Michael

Subject:

Request for Additional Information - License Amendment Request to Revise Technical Specification 3.4.12 (CAC Nos. MF7501 and MF7502)

Attachments: MF7501-RAI-SRXB.docx

Mike, By letter dated March 23, 2016 (Agencywide Documents Access and Management System (ADAMS)

Accession No. ML16084A588), Pacific Gas and Electric Company (PG&E) submitted License Amendment Request to revise Technical Specification 3.4.12, Low Temperature Overpressure Protection (LTOP) System, for Diablo Canyon Power Plant (DCPP), Units 1 and 2. The U.S. Nuclear Regulatory Commission (NRC) staff request PG&E to provide additional information to complete its review of the PG&E request. The request for additional information (RAI) is attached.

Draft RAI was transmitted to PG&E on August 9, 2016. You confirmed by e-mail dated August 17, 2016 that a clarification is not needed. Please treat this e-mail as formal transmittal of RAIs. You are requested to respond within 30 days from the date of this e-mail.

Thanks.

Balwant K. Singal Senior Project Manager (Diablo Canyon)

Nuclear Regulatory Commission Division of Operating Reactor Licensing Balwant.Singal@nrc.gov Tel: (301) 415-3016 Fax: (301) 415-1222 1

Hearing Identifier: NRR_PMDA Email Number: 3000 Mail Envelope Properties (Balwant.Singal@nrc.gov20160818082800)

Subject:

Request for Additional Information - License Amendment Request to Revise Technical Specification 3.4.12 (CAC Nos. MF7501 and MF7502)

Sent Date: 8/18/2016 8:28:36 AM Received Date: 8/18/2016 8:28:00 AM From: Singal, Balwant Created By: Balwant.Singal@nrc.gov Recipients:

"Richardson, Michael" <MJRm@pge.com>

Tracking Status: None Post Office:

Files Size Date & Time MESSAGE 1057 8/18/2016 8:28:00 AM MF7501-RAI-SRXB.docx 22282 Options Priority: Standard Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date:

Recipients Received: ZZZ

REQUEST FOR ADDITIONAL INFORMATION LICENSE AMENDMENT REQUEST TO REVISE TECHNICAL SPECIFICATION 3.4.12 PACIFIC GAS AND ELECTRIC COMPANY DIABLO CANYON POWER PLANT, UNITS 1 AND 2 DOCKET NOS. 50-275 AND 50-323 By letter dated March 23, 2016 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML16084A588), Pacific Gas and Electric Company (PG&E) submitted License Amendment Request (LAR) to revise Technical Specification (TS) 3.4.12, Low Temperature Overpressure Protection (LTOP) System, for Diablo Canyon Power Plant (DCPP), Units 1 and 2. The U.S. Nuclear Regulatory Commission (NRC) staff need the following additional information to complete its review of the PG&E request:

Request for Additional Information RAI-1 , LTOP Orifice - Key Design Features, to the Enclosure of letter dated March 23, 2016, states that the positive displacement pump (PDP) had a flowrate that was fairly constant near 100 gpm for all the reactor coolant system (RCS) operating pressure conditions. The replacement centrifugal pump (referred to as the normal charging pump or NCP) is stated to have a maximum flow of 120 gpm through the LTOP orifice. Table 1, LTOP Maximum Injection Flows, and Figure 1, LTOP Maximum Flows (gpm) vs. RCS Pressure (psia), of Enclosure to letter dated March 23, 2016 show that the maximum flow is reduced (on the order of 40 gpm) when changing from the PDP to the NCP, however, the flowrate can be larger with the NCP.

Please provide additional details on how the injection curves were determined and explain how the original maximum injection flow curve is still bounding now that there is the possibility of larger flowrates with the NCP.

RAI-2 to the Enclosure of letter dated March 23, 2016 states, in part, From the results presented in Figure 3, [LTOP Orifice - Pressure Drop - vs -

Flow Rate,] it can be observed that LTOP orifice limits the flow to less than 120 gpm.

While the data points for flowrate do not exceed 120 gpm on Figure 3 of Attachment 4, it is not clear that the LTOP orifice limits the flow to 120 gpm or if the testing just stopped at this point.

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Please provide additional information to demonstrate the pump is not capable of supplying more than 120 gpm through the LTOP orifice.

RAI-3

Figure 4, NCP aligned to LTOP Orifice - Acceptance Criteria, of Attachment 4 to the Enclosure of letter dated March 23, 2016 shows the pressure drop acceptance criteria for the LTOP orifice. This figure shows flowrates from 50 to 80 gpm, however, the maximum flowrate of the normal charging pump (NCP) through the LTOP orifice is stated to be 120 gpm. Please justify the use of 50 to 80 gpm (scaling on the X-axis) when the maximum flowrate is 120 gpm.

RAI-4

Figure 1, DCPP LTOP Mass Input Typical RCS Pressure Transient, of Attachment 5, Additional Information, to the Enclosure of letter dated March 23, 2016 shows a typical RCS pressure transient. In this figure, the Power Operated Relief Valve setpoint is given as 435 psig (gage), however, the curve (dotted line) is plotted as 435 psia (absolute). Given that the overshoot and undershoot values are based off of this value, please confirm that this is just an error on the example figure, rather than an error in any actual calculations.

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