ML15232A332
| ML15232A332 | |
| Person / Time | |
|---|---|
| Site: | Watts Bar  |
| Issue date: | 05/28/2015 |
| From: | Dion J Watts Bar Special Projects Branch |
| To: | Bryan R Tennessee Valley Authority |
| References | |
| TAC MF6153 | |
| Download: ML15232A332 (4) | |
Text
1 NRR-PMDAPEm Resource From:
Dion, Jeanne Sent:
Thursday, May 28, 2015 4:39 PM To:
rhbryan@tva.gov; Arent, Gordon <garent@tva.gov> (garent@tva.gov)
Cc:
Poole, Justin; Kuntz, Robert
Subject:
Draft REQUEST FOR ADDITIONAL INFORMATION MF6153.docx Attachments:
Draft REQUEST FOR ADDITIONAL INFORMATION MF6153.docx These are draft RAIs for the emergency diesel generator LAR on Unit 1. Let me know if you have any question or if you want a clarification call. As a reminder, I am out of the office May 29 to June 5-contact Robert Kuntz.
- Thanks, Jeanne Dion Project Manager Watts Bar Special Projects Branch Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation 301-415-1349
Hearing Identifier:
NRR_PMDA Email Number:
2316 Mail Envelope Properties (0B8884532E5C074E972B443F6E8F592E7DE601E209)
Subject:
Draft REQUEST FOR ADDITIONAL INFORMATION MF6153.docx Sent Date:
5/28/2015 4:38:36 PM Received Date:
5/28/2015 4:38:00 PM From:
Dion, Jeanne Created By:
Jeanne.Dion@nrc.gov Recipients:
"Poole, Justin" <Justin.Poole@nrc.gov>
Tracking Status: None "Kuntz, Robert" <Robert.Kuntz@nrc.gov>
Tracking Status: None "rhbryan@tva.gov" <rhbryan@tva.gov>
Tracking Status: None "Arent, Gordon <garent@tva.gov> (garent@tva.gov)" <garent@tva.gov>
Tracking Status: None Post Office:
HQCLSTR01.nrc.gov Files Size Date & Time MESSAGE 406 5/28/2015 4:38:00 PM Draft REQUEST FOR ADDITIONAL INFORMATION MF6153.docx 28262 Options Priority:
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Recipients Received:
Enclosure REQUEST FOR ADDITIONAL INFORMATION REGARDING DIESEL GENERATOR STEADY STATE FREQUENCY WATTS BAR NUCLEAR PLANT, UNIT 1 DOCKET NO. 50-390 (TAC NO. MF6153)
The following questions were developed as a result of the staffs review of the license amendment request (LAR) to modify the acceptance criteria for the diesel generator (DG) steady state frequency range provided in Technical Specification (TS) Surveillance Requirements (SRs) 3.8.1.7, 3.8.1.9, 3.8.1.11, 3.8.1.11, 3.8.1.12, 3.8.1.15, 3.8.1.19, and 3.8.1.21 for the Watts Bar Nuclear Plant, Unit 1 BACKGROUND TheWBNUnit1 LAR isbasedon an approach similar to WBNUnit2submittal for responsetoNUREG-0847,SupplementalSafetyEvaluationReport(SSER)22,OpenItem No. 32(Agencywide Documents Access and Management System (ADAMS) Accession No. ML14038A079). Tosupport the WBNdual-unitoperation with shared equipment,theDGvoltageandfrequencyshould be alignedforbothunits. The staff reviewed the LAR for Unit 1 and compared the information submitted for Unit 2 open item 32 and developed the following request for additional information:
QUESTIONS
- 1.
On page E-12 of Enclosure 1 it states Only major pumps in safety significant systems were evaluated in detail, because, as summarized in Table 3, the speed, load, flow, and NPSH are minimally impacted (i.e.,0.3%). However, staff notes that Table 3 summarizes flow rates only. Correct the statement to accurately reflect the record.
- 2.
On page E-14 of Enclosure 1 it states For 480 V motors, the speed reduction will be 0.3% to 0.63% due to greater voltage drop and higher rated motor slips.
Please confirm a bounding analysis was performed to validate the speed changes for 480 V motors. Please provide the reference to support the statement that the speed reduction will be0.3% to 0.63%.
- 3.
On page E-14 of Enclosure 1, Section 3.2.4 it states Theincreasedspeedduring operationwillresultinincreasedflowswhichinturnincreasesuctionsidelosses andreducesmarginbetweenavailableandrequiredNPSH. Thedecreased speedwillresultindecreasedflowswhichinturndecreasessuctionsidelosses andincreasesthemarginbetweenavailableandrequiredNPSH.
The staff notes that the NPSH parameters in Table 4, on page E-15 are not consistent with the statement in Section 3.2.4 statement. Please provide an explanation of the specific variations in the NPSH parameters due to frequency variation (+/- 0.3%).
- 4.
On page E-16 of Enclosure 1, Table 5 provides a summary of effective brake horsepower (BHP) at the allowable frequency range. The staff notes that at nominal frequency, the effective BHP is higher than the nominal HP for all motors except for the Containment Spray (CS) pump. The staff also notes a difference in BHP for the Centrifugal Charging (CC) pumps between the two units (Reference Table 5 in Enclosure 1 for Unit 2 SSER submittal). Please explain the reason for the differences.
- 5.
On Page E-14 of Enclosure 1 it states To support Westinghouses DG frequency range evaluation, Flowserve, the ECCS [Emergency Core Cooling System] pump vendor provided input as to the expected performance of the Centrifugal Charging pumps and Intermediate Head Safety Injection pumps for continuous operation up to 30 days. Flowserve concluded that both pumps are expected to undergo minor cavitation damage, but would remain operational for the 30 days, with gradual decline in pump/power performance. Additional detail regarding the impact of minor cavitation damage on pump performance is provided in Flowserve Report GS-8236, Revision 3, Run-Out Flow Operation Capability Analysis (Reference 18).
Please submit the above referenced Flowserve Report.
- 6.
Please provide basis/reference for the following statements:
- a.
On page E-16 of Enclosure 1 it states The BHP with a speed variation of
+/-0.3 will vary by 1.0%.
- b.
On page E-12 of Enclosure 1 it states The stroke time will be less than 0.8% longer.