ML20207E243
| ML20207E243 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 05/11/1999 |
| From: | Assa R NRC (Affiliation Not Assigned) |
| To: | NRC (Affiliation Not Assigned) |
| References | |
| GL-95-07, GL-95-7, NUDOCS 9906040198 | |
| Download: ML20207E243 (3) | |
Text
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.t May;11:, 1999 MEMORANDUM TO: Docket File.
FROM:
Ramin R. Assa, Project Manager, Section 1 Original signed by:
Project Directorate il Division of Licensing Project Management Office of Nuclear Reactor Regulation
SUBJECT:
VOGTLE UNITS 1 AND 2 - PLACEMENT OF A DOCUMENT IN TH2 PUBLIC DOCUMENT ROOM RELATED TO GL 95-07 p gnUC DCCUM3I bbbH Please place the attached Request for Additional Information (RAI) in the NRC's Public Document Room. The attached RAI was fa'M, tNaf,lo dr.
Bailey of the Southern Nuclear Operating Company, Inc. (SNC). The attachment will be used to facilitate discussions during an upcoming conference call between the NRC and SNC staff. This document does not constitute a formal request for information nor does it represent a formal NRC staff position.
Docket Nos. 50-424 and 50-425
Attachment:
As stated Distribution:
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May 11, 1999 l
MEMORANDUM TO: Docket File FROM:
Ramin R. Assa, Project Manager, Section 1 Project Directorate 11 Division of Licensing Project Management
' Office of Nuclear Reactor Regulation
SUBJECT:
VOGTLE UNITS 1 AND 2 - PLACEMENT OF A DOCUMENT IN THE PUBLIC DOCUMENT ROOM RELATED TO GL 95-07 j
Please place the attached Request for Additional Information (RAl) in the NRC's Public Document Room. The attached RAI was faxed, today, to Mr. Jim Bailey of the Southern Nuclear Operating Company, Inc. (SNC). The attachment will be used to facilitate discussions during an upcoming conference call between the NRC and SNC staff. This document does not constitute a formal request for information nor does it represent a formal NRC staff position.
4 Docket Nos. 50-424 and 50-425
Attachment:
As stated u-
,y Vogtle
- 1. Your February 9,1998, submittal states that the temperature of the residual heat removal (RHR) loop suction valves,1/2HV-8701 A/B and 1/2HV-8702A/B, increases / decreases as reactor coolant system (RCS) temperature increases / decreases and that the valves are not susceptible to pressure locking because as the RCS temperature decreases pressure in the bonnets of the valves will decrease. Explain if any valve or actuator structurallimits are exceeded during heatup of the RCS due to increased bonnet pressure.
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- 2. Your submittal dated July 26,1996, states that the pressurizer power operated relief valve (PORV) block valves,1/2HV-8000A/B, are not susceptible to pressure locking because temperature of the valves trends with pressurizer steam temperature and as temperature of the steam decreases, pressure in the bonnets of the valves will decrease. During a steam generator tube rupture event (SGTR), the RCS pressure will decrease and the temperature of the steam space in the pressurizer will rapidly decrease. However, the temperature of the piping and of the pressurizer (metal) will decrease at a slower rate than the steam in the pressurizer. The NRC staff considers that the pressure of the steam in the bonnets of 1/2HV-8000A/B will be higher than pressurizer pressure until the temperature of the steam j
in the pressurizer is the same as the pressurizer and piping. Explain how long it will take for the temperature of the valves to equalize with the temperature of the steam in the pressurizer and the temperature of the valves when they ; ; required to open during a SGTR.
- 3. Explain why RHR to charging pump and Si valves,1/2HV-8804A/B and 1/2HV-8807A/B, are not susceptible to pressure locking following operation of the RHR system in the shutdown cooling mode.
- 4. Your technical specifications require an operable emergency core cooling system injection flow path from the refueling water storage tank (RWST) to the RCS via the RHR pump when RCS temperature is less that 350*F. During the shutdown cooling mode of operation, the RHR pump suction valve to the RWST,1/2HV-8812A/B, is shut. Is the valve required to be opened to realign the RHR pump to inject into the RCS? If so, explain why the valve is not susceptible to hydraulic or thermal induced pressure locking?
- 5. Do TSs credit the use of a gravity boration path to the charging pumps? If so, are there any valves in the gravity boration path that may be susceptible to pressure locking following operation of the boric acid pumps?
- 6. Comment: NRC Inspection Report (97-04) states that the licensee's analysis to operate the boron injection tank discharge valves,1/2HV-8801 A/B, and the containment spray pump discharge isolation valves,1/2HV-9001 A/B at locked rotor conditions was an unacceptable pressure locking solution. The staff now accepts operation of actuators for approximately 1 second at locked rotor conditions because testing performed by Idaho National Engineering and Environmental Laboratory (NUREG/CR-6478) demonstrates that the capability of the actuator do not degrade. Use of the Commonwealth Edison pressure locking methodology (1/2HV-8000A/B) and cycling valves following evolutions that create pressure locking conditions (1/2HV-9001 A/B) are acceptable corrective actions.
Attachment