ML120250177

Email, Request for Additional Information, Round 2, Amendment Request to Revise Technical Specification 3.3.6.1, Primary Containment and Drywell Isolation Instrumentation, for Main Steam Tunnel Temperature Function Setpoints

ML120250177
Person / Time
Site:	River Bend
Issue date:	01/25/2012
From:	Wang A Plant Licensing Branch IV
To:	Burmeister B, Clark J Entergy Operations
Wang, A B, NRR/DORL/LPLIV, 415-1445
References
TAC ME6843
Download: ML120250177 (3)

Text

From: Wang, Alan Sent: Wednesday, January 25, 2012 10:27 AM To: BURMEISTER, BARRY M; Joseph Clark (JCLARK@entergy.com)

Cc: Lent, Susan; Burkhardt, Janet

Subject:

MS Tunnel Temps (ME6843)

Joey and Barry, By letter dated July 27, 2011, as supplemented on September 16, 2011, (Agencywide Documents Access and Management System (ADAMS) Accession No. ML11214A093 and ML11263A013, respectively), Entergy Operations, Inc (Entergy, the licensee) submitted Entergy Letter RBG-47157, License Amendment Withdrawal and Request - Changes to Technical specification 3.3.6.1, Primary Containment and Drywell Isolation Instrumentation , to revise the allowable value setpoints for the Main Steam Tunnel Temperature functions 1.e, 3.f, and 4.h.

The NRC staff has determined that the following additional information is needed to complete our review of this amendment. This request for additional information (RAI) was discussed with Mr. Barry Burmeister of your staff on January 25, 2012, and it was agreed that a response would be provided within 30 days from the issuance 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. The following RAIs are related to July 27, 2011 LAR:

1. Attachment 1, Section 2 of the LAR (ADAMS Accession No. ML11214A093), identifies a proposed Note to be added to Surveillance Requirement (SR) in accordance with the Technical Specification Task Force (TSTF)-493, Clarify Application of Setpoint Methodology for LSSS Functions. To support the NRC staff review, please identify the reference to the plant specific program used to calculate the As-Found Tolerance (AFT), and As-Left Tolerance (ALT) for the main steam tunnel temperature functions.

2. Attachment 1, Section 3.0 of the LAR (ADAMS Accession No. ML11214A093), explains that River Bend Station (RBS) has determined that during the summer months the main steam tunnel temperature high alarm has reached the trip setpoints. Please provide a summary of the data collected, including the time duration and the receipt of the high temperature alarms.

3. Attachment 1, Section 4.1 of the LAR (ADAMS Accession No. ML11214A093), states that as part of this amendment request, the analytical limit for the main steam tunnel temperature

- high is increased from 154°F to 194.77°F. This sentence implies that Entergy is requesting approval of this change as part of the LAR, even thought other sections of the LAR implied that the AL has been already modified. In addition, please note that comment 4.1 in Entergys September 16, 2011 letter (ADAMS Accession No. ML11263A013) states that the AL was previously changed per RBS Engineering Change EC-26710 and Calculation G13.18.14.1-036. Please clarify.

4. The summary calculation for the main steam tunnel high-high temperature setpoint provided in Entergys September 16, 2011 letter (ADAMS Accession No. ML11263A013) does not provide sufficient information to make a determination that adequate margin has been established when calculating the Allowable Value (AV) Setpoint to allow for all instrument channel performance uncertainties. To support the NRC staff, please:

a. Confirm that the summary calculation for the steam generator water high-high level setpoint is in accordance with NEDC-31336, General Electric Instrument Setpoint Methodology. Section 4.3 of the LAR states that the methodology used in determining Nuclear Steam Supply Shutoff (NSSS) safety system is similar to that used for balance of plant safety setpoints, which is documented in NEDC-31336.

b. Provide the source for the values identified in this calculation.

c. Provide data to show that tolerance limits for this calculation have been based on a statistically sufficient quantity of sample data to bound these values and provide a confidence that the interval contains 95 percent of the population, with a 95% confidence level.

d. Describe the algorithm or equation used to calculate the AV setpoint and how the uncertainty terms were combined in the equation and how these terms represent their contribution to total error. Also, please identify the terms that are considered random and independent, random and dependent, and non-random.

e. Provide the basis for calculating the allowable value (AV), as found tolerance, and as left tolerance. Demonstrate that with the instrument as-found value at the AV, under the worst-case condition the channel trip function will be achieved with a 95% probability before the AL is reached.

f. Provide information to clarify comment 4.1 in Entergys September 16, 2011 letter (ADAMS Accession No. ML11263A013), which states Analytical Value previously changed from 154°F to 194.7°F.... This seems to be a mistake, since this change appears to be referring to the Analytical Limit.

g. Please clarify the calculations referenced in this letter. Entergys Summary to G13.18.6.1-E31*009 provided in its September 16, 2011 letter (ADAMS Accession No. ML11263A013) identifies calculations listed in reference section 3.3, 3.8, 3.12, and 3.27.

5. Attachment 1, Section 4.2 of the LAR (ADAMS Accession No. ML11214A093), states that the USAR tables 5.2-7 and 5.2-8 indicate that the main steam tunnel ambient temperature provides alarm and isolation. Please clarify if the temperature alarms have two setpoints, one for alarm and one for isolation, or if the high temperature alarms have only one setpoint to perform both functions of isolation and alarm.

Alan Wang Project Manager (River Bend Station)

Nuclear Regulatory Commission Division of Operating Reactor Licensing Alan.Wang@NRC.gov Tel: (301) 415-1445 Fax: (301) 415-1222