ML21225A039

NRR E-mail Capture - Preliminary Request for Additional Information Regarding Clinton Request to Revise Degraded Voltage Instrumentation Setpoints

ML21225A039
Person / Time
Site:	Clinton
Issue date:	08/13/2021
From:	Joel Wiebe NRC/NRR/DORL/LPL3
To:	Mathews M, Nicely K Exelon Generation Co
References
L-2021-LLA-0005
Download: ML21225A039 (5)

Text

From:

Wiebe, Joel Sent:

Friday, August 13, 2021 7:46 AM To:

Nicely, Ken M.:(GenCo-Nuc) (ken.nicely@exeloncorp.com)

Cc:

Mathews, Mitchel A:(Exelon Nuclear)

Subject:

Preliminary Request for Additional Information Regarding Clinton Request to revise Degraded Voltage Instrumentation Setpoints (EPID L-2021-LLA-0005)

Hi Ken/Mitch Let me know by August 20, 2021, if you want a clarification discussion regarding these RAIs. If not, these RAIs are the final RAIs and a response is requested by September 13, 2021.

Joel By application dated January 20, 2021 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML21020A053), Exelon Generation Company, LLC (the licensee) requested a license amendment (LAR) for Clinton Power Station (CPS) to revise the degraded voltage reset and drop-out allowable values that are listed in Technical Specifications (TS) 3.3.8.1, "Loss of Power (LOP) Instrumentation," Table 3.3.8.1-1, "Loss of Power Instrumentation."

The NRC staff has identified the need for the following additional information to complete the review of the LAR.

Regulatory Basis The regulation at Title 10 of the Code of Federal Regulations (10 CFR) 50.36, Technical specifications, requires, in part, that each license authorizing operation of a utilization facility include TSs. The regulation at 10 CFR 50.36(c) requires that TSs include items in specific categories, including: (1) safety limits, limiting safety system settings, and limiting control settings; (2) limiting conditions for operation; (3) surveillance requirements; (4) design features; and (5) administrative controls.

The regulation at 10 CFR 50.36(c)(1)(ii)(A) states that limiting safety system settings are settings for automatic protective devices related to those variables having significant safety functions. Where a limiting safety system setting is specified for a variable on which a safety limit has been placed, the setting be so chosen that automatic protective action will correct the abnormal situation before a safety limit is exceeded.

The licensing basis for degraded voltage protection is captured in the Clinton Updated Safety Analysis Report (USAR) and corresponding Technical Specifications. The Clinton USAR Section 8.3.1.1.2, Unit Class 1E A-C Power System, Revision 21, March 31, 2020 (ADAMS Accession No. ML20105A259), contains a description of the Clinton undervoltage protection scheme including the basis for the degraded voltage relay setpoints.

Requests for Additional Information

1) On Page 4 of Attachment 1 of the LAR, the licensee states: The basis for the dropout Allowable Value lower limit ensures adequate voltage to start plant equipment under non-LOCA [Loss of Coolant Accident] loading conditions.

On Page 16 of Calculation IP-E-0032 (Attachment 4 of LAR), the licensee states: Per Section 8.1.3 of Reference 6.7.3, the Analytical Limit for the minimum degraded voltage relay Dropout (i.e. trip) voltage is 4035 Volts (V) on the primary bus. All loads connected to Buses 1A1, 1B1 and 1C1 have acceptable voltage under steady state LOCA Loading at 4035 V.

Explain the relationship between the above non-LOCA and LOCA loading statements with respect to the degraded voltage relay dropout voltage.

2) The licensee has provided the Analytical Limits (Voltage) for reset and drop out values on Pages 15-16 of Calculation IP-E-0032 [Attach 4 of LAR], which are based on Reference 6.7.3 of the Calculation IP-E-0032 [Reference 6.7.3: Calculation No. 19-AK-13, Revision 4, 4A, 4B and 4C, "Analysis of Load Flow, Short Circuit and Motor Starting using ETAP Power Station.]

Provide information to clarify whether the analytical limits for degraded voltage reset and drop out values are being changed in this LAR based on the latest revision of referenced Calculation No. 19-AK-13. If yes, please provide supplemental information relating to analytical limits, such as the relevant summary of Calculation No. 19-AK-13, Revision 4, 4A, 4B and 4C, "Analysis of Load Flow, Short Circuit and Motor Starting using ETAP Power Station.

Other items which are not RAIs:

On Page 51 of 219 of the LAR in Attachment 4, CALCULATION No. IP-E-0032," (Sheet 29 of

50) the licensee calculated the total negative random errors by equation below:

The following items need clarification:

1. Is the ATE - (Negative Accuracy Temperature Effect, in highlight text) correct or a typo? The NRC staff verified that -0.0355 is the value of the PSE- (Negative Power Supply Effect).

2. Is it missing a minus sign in the highlight spot?

The NRC Staff noted that the result of this equation is correct.

Hearing Identifier:

NRR_DRMA Email Number:

1314 Mail Envelope Properties (MN2PR09MB4971A7DE8DC990B377338FDE8BFA9)

Subject:

Preliminary Request for Additional Information Regarding Clinton Request to revise Degraded Voltage Instrumentation Setpoints (EPID L-2021-LLA-0005)

Sent Date:

8/13/2021 7:45:42 AM Received Date:

8/13/2021 7:45:00 AM From:

Wiebe, Joel Created By:

Joel.Wiebe@nrc.gov Recipients:

"Mathews, Mitchel A:(Exelon Nuclear)" <Mitchel.Mathews@exeloncorp.com>

Tracking Status: None "Nicely, Ken M.:(GenCo-Nuc) (ken.nicely@exeloncorp.com)" <ken.nicely@exeloncorp.com>

Tracking Status: None Post Office:

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