ML14027A316
| ML14027A316 | |
| Person / Time | |
|---|---|
| Site: | Quad Cities  |
| Issue date: | 01/24/2014 |
| From: | Mozafari B Plant Licensing Branch 1 |
| To: | Nicely K Exelon Corp |
| References | |
| MF2297, MF2298 | |
| Download: ML14027A316 (4) | |
Text
1 NRR-PMDAPEm Resource From:
Mozafari, Brenda Sent:
Friday, January 24, 2014 6:58 PM To:
Nicely, Ken M.:(GenCo-Nuc) (ken.nicely@exeloncorp.com)
Cc:
Purnell, Blake; Tate, Travis
Subject:
QUAD CITIES, UNITS 1 AND 2 - SECOND RAI for LAR request re: battery surveillance SRs (TAC NOS. MF2297 AND MF 2298)
Tracking Tracking:
Recipient Read Nicely, Ken M.:(GenCo-Nuc)
(ken.nicely@exeloncorp.com)
Purnell, Blake Read: 1/27/2014 8:02 AM Tate, Travis
- Ken,
SUBJECT:
QUAD CITIES NUCLEAR POWER STATION, UNITS 1 AND 2 REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST TO REVISE BATTERY SURVEILLANCE REQUIREMENTS (TAC NOS. MF2297 AND MF 2298)
By letter dated June 10, 2013 (Agencywide Documents Access and Management System Accession Number ML13161A315), Exelon Generation Company, LLC (EGC, the licensee) submitted an amendment to revise the Renewed Facility Operating License for Quad Cities Nuclear Power Station (QCNPS), Units 1 and 2. The proposed change would modify Technical Specifications (TS) Surveillance Requirement (SR) 3.8.4.2 and SR 3.8.4.5 by adding new acceptance criteria for total battery connection resistance.
During the review of the information provided, we have identified a need for additional information (below) to complete our safety evaluation. If a clarification call is needed, contact me to set up a time. These RAI questions will be considered final after such a call is completed and have been placed in ADAMS. Your written response should be provided to the me within 45 days of this emailed RAI request.
SECOND REQUEST FOR ADDITIONAL INFORMATION REGARDING QUAD CITIES NUCLEAR POWER STATION, UNITS 1 AND 2 LICENSE AMENDMENT REQUEST TO REVISE BATTERY SURVEILLANCE REQUIREMENTS DOCKET NOS. 50-254 AND 50-265 The Electrical Engineering Branch (EEEB) staff has the following questions based on its review of the Exelon Generation Company, LLC (EGC, the licensee) license amendment request (LAR) dated June 10, 2013, as supplemented by letter dated October 24, 2013, regarding the proposed revision to battery Technical Specification (TS) surveillance requirement (SRs):
BACKGROUND Current QCNPS TS SR 3.8.4.2 and SR 3.8.4.5 require EGC to verify that safety-related batteries would remain operable if each of the inter-cell and terminal connections was at the maximum resistance value of 150 micro-ohms. The TS SR value of 150 micro-ohm connection resistance was a generic value agreed by the industry and the NRC. In the LAR, EGC considered this generic value to be nonconservative and proposed a revision to SRs 3.8.4.2 and 3.8.4.5 to add new acceptance criteria for total battery connection resistance. Specifically, the proposed change would add a requirement to:
2 Verify total battery connection resistance is:
- a. 6.0E-3 ohm for each 250 VDC subsystem
- b. 2.4E-3 ohm for each 125 VDC subsystem TS operability considerations require that structures, systems and components meet all surveillance requirements. To demonstrate operability of the plant specific battery system using the current TS requirements, the total battery connection resistance has to be computed based on the following:
- 1. Each inter-cell, inter-tier, inter-rack and terminal post connection at a maximum resistance of 150 micro-ohms;
- 2. The total connection resistance of the battery system to be the sum of all the connections calculated in (1) above plus the resistance of any interconnecting cables used between the inter-rack and inter-tier connections;
- 3. Instrument uncertainties added to the measured connection resistance values.
QUESTIONS
- 1. In response to NRC Request 1, the licensee stated that the proposed total battery connection resistance limits are the operability limits of the overall battery connection resistance. As indicated in the LAR, the total battery connection resistance values include inter-cell and terminal connection resistances.
Validate that the proposed total connection resistance values of 6.0E-3 ohm for the 250VDC subsystem and 2.4E-3 for the 125VDC subsystem, when used to demonstrate operability of the battery system(s),
include measurement uncertainties, the sum of cable resistances and inter-tier, inter-cell, inter-rack, and terminal post connections resistances associated with the battery system, and the minimum voltage requirements considered in the plant design.
- 2. In response to NRC Request 5, the licensee stated that the inter-cell, inter-tier, inter-rack, and terminal connection resistance limits will ensure that the minimum required battery terminal voltage (i.e., 105 VDC) for the 125 VDC batteries will be maintained. The response to NRC Request 2 states that the jumper cable resistance is excluded from the inter-cell measurements because it could mask a degrading inter-cell connector.
Clarify how the minimum required battery terminal voltages (i.e., 105 VDC and 210 VDC) for the 125 and 250 VDC batteries respectively, will be maintained without considering the resistance of the cables associated with the battery.
- 3. In response to NRC Request 7, the licensee stated that the resistances for inter-cell connectors, terminal connectors and jumper cables are temperature corrected to 120°F (i.e., 50°C), the maximum temperature in the turbine building where the batteries are located. The licensee also stated that the voltage VMin, which is used to calculate the resistance RMargin due to the remaining battery margin, is temperature corrected to 65°F (i.e., 18.33 °C).
The staff notes that typical insulated power cables have a rated temperature of 90°C (i.e., 194°F), and thus, analytical calculations conservatively use a bounding temperature of 90°C.
- a. Provide the temperature correction factor for RMargin. If RMargin is temperature corrected to 65°F, clarify if adding RMargin to RVendor, the vendors resistance that is temperature corrected to 120°F, is conservative.
3
- b. Explain how the change in resistance due to load current heating effect and the resultant increase in temperature of all current carrying components is accounted for in the RTotal-Allow value and the above total battery connection resistance limits.
- 4. In Attachment 4 of the LAR, the licensee stated that the minimum required battery voltages used to determine the maximum allowable connection resistance value are105 VDC and 210 VDC for the 125 and 250 VDC batteries respectively.
The staff notes that equipment manufacturers typically specify 210V and 105V as the minimum allowable voltage at the device terminals.
Validate that the minimum required battery voltages at the batteries terminals are adequate for operability of all DC equipment after allowing for voltage drop due to intervening conductors and connections.
Hearing Identifier:
NRR_PMDA Email Number:
1042 Mail Envelope Properties (Brenda.Mozafari@nrc.gov20140124185800)
Subject:
QUAD CITIES, UNITS 1 AND 2 - SECOND RAI for LAR request re: battery surveillance SRs (TAC NOS. MF2297 AND MF 2298)
Sent Date:
1/24/2014 6:58:18 PM Received Date:
1/24/2014 6:58:00 PM From:
Mozafari, Brenda Created By:
Brenda.Mozafari@nrc.gov Recipients:
"Purnell, Blake" <Blake.Purnell@nrc.gov>
Tracking Status:: Response: Read : 1/27/2014 8:02:00 AM "Tate, Travis" <Travis.Tate@nrc.gov>
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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