ML070950045
| ML070950045 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 04/03/2007 |
| From: | Tam P NRC/NRR/ADRO/DORL/LPLIII-1 |
| To: | Loeffler R, Salamon G Nuclear Management Co |
| References | |
| TAC MD4095 | |
| Download: ML070950045 (2) | |
Text
From:
Peter Tam To:
Loeffler, Rick; Salamon, Gabor Date:
04/03/2007 6:07:07 PM
Subject:
Monticello - Draft RAI re. LPCI Loop Select Logic Surveillance (TAC MD4095)
Rick:
We are reviewing your 1/29/07 application for amendment. Our Instrumentation and Controls Branch has developed the following draft questions that we would like to discuss with you in a conference call:
1.
The second paragraph of Section 5.3 of Enclosure 1, in part, states: The LPCI loop select time delay relays have very specific functions which do not specifically relate to accident timing parameters, Analytical Limits are not readily apparent. In addition, the second paragraph of Section 5.2 states that: In MODES 1, 2, and 3, operation of the LPCI loop select logic functions is required to ensure that no single failure can prevent successfully selecting the unbroken recirculation loop for LPCI injection. Since LPCI mode of the Residual Heat Removal system is one of the Emergency Core Cooling Systems, please provide the analyzed value of the time available to achieve successful LPCI injection so that staff can determine that adequate margin is available in the setting of the time delay relays with or without loss of offsite power.
2.
LPCI injection flow will only take place when the reactor pressure reduces to a value below the pump shut-off head. From the submittal it is not clear as to how much time is available after the reactor steam dome pressure falls below the pump shut-off head and the LPCI flow has to be established. Please provide this information along with the basis of this information.
3.
Please advise us of the setpoint methodology and the method used for calculating the setpoint.
4.
In the second paragraph of Section 5.3 of Enclosure 1 it is stated that: The total of all the nominal time delay settings is 3 seconds, and does not approach the 15 seconds available for completion. Totaling the upper adjustment limit for the three time delay relays involved in LPCI loop selection adds up to a total of 9 seconds, and does not approach the 15 second requirement Please explain how the total time delay setting can be 3 seconds when the proposed allowable value time setting for the three relays are 2.97, 0.75, and 0.75 seconds.
Please clarify the statement as needed to avoid confusion.
5.
In the licensee response to item 1 of Generic Letter, GL 91-04 it is stated that: Since there was no requirement in the custom TS to test the time delay feature, calibration data from surveillance or maintenance records was not available for the LPCI loop select logic time delay relays to directly establish their drift characteristics. Please provide justification for the drift values used for ETR14D3A relays. Also please provide the nominal trip setpoint values of the time delay relays.
6.
In the licensee response to item 1 of GL 91-04 the licensee has assumed that percentage drift for ETR14D3A (Range 0.15 to 3.0 seconds) and that of ETR143B (Range 0.55 to 15 seconds) is same. The adjustable time delay ranges for these relays are significantly different. Please provide the basis of this assumption including any available data to support this assumption. In addition, the 92 day drift data has been extrapolated for use in 30 month drift calculation. Please provide the basis with the reference used for extrapolating the 92 day drift data to 30 month drift calculation.
This e-mail aims solely to prepare you and others for the proposed conference call. It does not formally request for additional information, and it does not convey an official NRC staff position.
Peter S. Tam, Senior Project Manager Plant Licensing Branch III-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation e-mail: pst@nrc.gov Tel.: 301-415-1451 CC:
Gursharan Singh Mail Envelope Properties (4612D00B.74D : 12 : 35330)
Subject:
Monticello - Draft RAI re. LPCI Loop Select Logic Surveillance (TAC MD4095)
Creation Date 04/03/2007 6:07:07 PM From:
Peter Tam Created By:
PST@nrc.gov Recipients Action Date & Time nmcco.com Transferred 04/03/2007 6:07:26 PM Gabor.Salamon (Gabor Salamon)
Richard.Loeffler (Rick Loeffler) nrc.gov OWGWPO04.HQGWDO01 Delivered 04/03/2007 6:07:13 PM GXS4 CC (Gursharan Singh)
Opened 04/04/2007 8:19:48 AM Post Office Delivered Route nmcco.com OWGWPO04.HQGWDO01 04/03/2007 6:07:13 PM nrc.gov Files Size Date & Time MESSAGE 5029 04/03/2007 6:07:07 PM Options Auto Delete:
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