ML100630301

Email, Request for Additional Information, License Amendment Request to Revise TS 3.4.15, RCS Leakage Detection Instrumentation Operability Requirements and Actions

ML100630301
Person / Time
Site:	Diablo Canyon
Issue date:	03/03/2010
From:	Wang A Plant Licensing Branch IV
To:	Baldwin T, Parker L Pacific Gas & Electric Co
Wang, A B, NRR/DORL/LPLIV, 415-1445
References
TAC ME1644, TAC ME1645
Download: ML100630301 (3)

Text

From: Wang, Alan Sent: Wednesday, March 03, 2010 10:17 PM To: Baldwin, Thomas (DCPP); Larry Parker Cc: Ken Schrader; Burkhardt, Janet; Lent, Susan

Subject:

Request for Additional Information Regarding Reator Coolant System (RCS)

Leakage Detection Amendment (ME1644 and ME1645)

Tom and Larry, By letter dated July 3, 2009 (Agencywide Documents Access & Management System (ADAMS)

Accession No. ML091960177), Pacific Gas and Electric Company (PG&E), the licensee for Diablo Canyon Power Plant, Unit Nos 1 and 2 (DCPP), requested a change to Technical Specifications 3.4.15, RCS Leakage Detection Instrumentation.

The US Nuclear Regulatory Commission (NRC) staff has determined that the following additional information is needed to complete its review of the subject license amendment request for DCPP. This request was discussed with Ken Schrader of your staff on March 3, 2010, and it was agreed that a response would be provided within 45 days of receipt of this email. If circumstances result in the need to revise the requested response date, please contact me at (301) 415-1445 or via e-mail at Alan.Wang@nrc.gov.

REQUEST FOR ADDITIONAL INFORMATION

1)

Background:

Position C.7 of Regulatory Guide 1.45, Rev 0 (RG 1.45) recommends indicators and alarms for each leakage detection system be provided in the main control room. The current DCPP Technical Specifications (TS) 3.4.15 Bases states, The need to evaluate the severity of an alarm or an indication is important to operators.

Issue: The revised TS 3.4.15 Bases section for RCS Leakage Detection Instrumentation removes the control room alarms from the TS Bases discussion. The proposed change adds the wording, OPERABILITY of the RCS leakage detection instrumentation includes the control room indication associated with the instrumentation but does not include control room alarms or alarm setpoints. The removal of the control room alarms from the TS Bases discussion is a departure from the standard technical specifications.

Allowing operation without functional alarms on RCS leakage detection instrumentation could extend the amount of time for control room operators to become aware of an increase in containment radioactivity.

Request: Retain the discussion of alarms in the TS Bases discussion or provide justification for their removal. Include a discussion of the reason for removing the control room alarms and setpoints from TS operability discussion, the benefit obtained by making this change, and the program that would maintain control of these alarms and setpoints once removed from TS.

2)

Background:

Per DCPP FSAR section 11.4.4.1, Alarm Setpoints, alarm setpoints for process and area radiation monitors are based on protection of public health and safety, plant personnel health and safety, and maintaining efficient plant operation.

Issue: The sensitivity of the containment atmosphere gaseous radioactivity monitor is limited by low RCS activity, but the instrument is still a valuable tool for RCS leakage detection. In order to meet statement of FSAR section 11.4.4.1 above, the alarm setpoints should be as conservative as is reasonable to detect leakage at current RCS activity levels.

Request: Describe how the alarm setpoints for the containment gaseous radioactivity monitor will be determined for operation under the normal, low RCS activity level.

E-mail Properties Mail Envelope Properties (C0A338EE37A11447B136119705BF9A3F5A64A37D97)

Subject:

Request for Additional Information Regarding Reator Coolant System (RCS)

Leakage Detection Amendment (ME1644 and ME1645)

Sent Date: 3/3/2010 10:17:27 PM Received Date: 3/3/2010 10:17:27 PM From: Wang, Alan Created By: Alan.Wang@nrc.gov Recipients:

TRB1@pge.com (Baldwin, Thomas (DCPP))

Tracking Status: None LMP1@pge.com (Larry Parker)

Tracking Status: None KJSe@pge.com (Ken Schrader)

Tracking Status: None Janet.Burkhardt@nrc.gov (Burkhardt, Janet)

Tracking Status: None Susan.Lent@nrc.gov (Lent, Susan)

Tracking Status: None Post Office:

HQCLSTR02.nrc.gov Files Size Date & Time MESSAGE 14985 3/3/2010 Options Expiration Date:

Priority: olImportanceNormal ReplyRequested: False Return Notification: False

Sensitivity: olNormal Recipients received: