ML13333A336
| ML13333A336 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 12/21/1978 |
| From: | Ziemann D Office of Nuclear Reactor Regulation |
| To: | James Drake SOUTHERN CALIFORNIA EDISON CO. |
| References | |
| TASK-05-11.A, TASK-5-11.A, TASK-RR NUDOCS 7901080355 | |
| Download: ML13333A336 (7) | |
Text
Docket No. 50-206 DEC 2 1 1978 Mr. James H. Drake Vice President Southern California Edison Company 2244 Walnut Grove Avenue Post Office Box 800 Rosemead, California 91770
Dear Mr. Drake:
RE: VERIFICATION OF PLANT INFORMATION ON SEP TOPIC V-11A, "REQUIREMENTS FOR ISOLATION OF HIGH AND LO1 PRESSURE SYSTEMS' Our initial review of SEP Safety Topic V-11.A has been completed. The enclosed table presents docketed information on reactor coolant system interfaces with low pressure systems. Also included is plant information obtained during our recent safe shutdown review of your facility.
Only systems that had direct interfaces with the primary system were considered. These were the water cleanup systems, the ECCS, the sampling systems, and the RHR systems. High pressure systems connected to the primary system that indirectly interfaced with a low pressure system (i.e., service water or component cooling through a heat exchanger) were not considered. Systems designed to operate at high pressure were also not included (i.e., B R isolation condenser) except for the high pressure RHR system on several BWRs, which were included for completeness.
For PWRs the seal injection system was included because it was identified in a memo from E. G. Case to R. F. Fraley (Ref. 1) as having the potential to inadvertently overpressurize the water makeup tank. For SWRs the reactor vessel head spray cooling system was included because the potential for overpressurizing the condensate storage tank, if not properly vented, may exist.
790108 0:5 oFFIcE SURNAME DATE*
NRC FORM 318 (9-76) NRCM 0240
- UJ S. GOVERNMENT PRINTING OFFICE: 1976 -
626-624
Mr. James H. Drake
- 2 Isolation requirements for the ECCS system injection lines as stated in Standard Review Plan (SRP) 6.3 are listed below:
(1) One or more check valves in series with a normally closed motor-operated valve. The motor-operated valve is to be opened upon receipt of a safety injection signal once the reactor coolant pressure has decreased below the ECCS design pressure.
(2) Three check valves in series.
(3) Two check valves in series, provided that there are design provisions to permit periodic testing of the check valves for leak tightness and the testing is performed at least annually.
The isolation requirements for the RHR system as stated in Branch Technical Position IBTP-RSB 5-1 are listed below:
(1) The following shall be provided in the suction side of the RHR system to isolate it from the RCS.
a) Isolation shall be provided by at least two power-operated valves in series. The valve positions shall be indicated in the control room.
(b) The valves shall have independent diverse interlocks to prevent the valves from being opened unless the RCS pressure is below the RHR system design pressure. Failure of a power supply shall not cause any valve to change positions.
(c)
The valves shall have independent diverse interlocks to protect against one or both valves being open during an RCS increase above the design pressure of the RHR system.
(2) One of the following shall be provided on the discharge side of the RHR system to isolate it from the RCS:
(a) The valves, position indicators, and interlocks described in item 1(a) -
(c),
(b) One or more check valves in series with a normally closed power-operated valve.
The power-operated valve position shall be indicated in the control room.
If the RHR discharge line is used for an ECCS futctioi,. te power-operated valve is to be opened upon receipt of a safety injection signal once the reactor coolant pressure has decreased, OFFICE~
J SURNAME NRC FORM 318 (9-76)
NRCM 0240 U. S. GOVERNMENT PRINTING OFFICE: 1976 - 626-624
fr. James H. Drake
- 3 (c) Three check valves in series or (d) Two check valves in series, provided that there are design provisions to permit periodic testing of the check valves for leak tightness and the testing is performed at least annually.
Isolation requirements for the cleanup and sampling system are dictated by the requirements of SRP 6.2.4 and GDC 55 related to lines that pene trate the primary containment boundary and are listed below:
(1) One locked closed isolation valve--inside and one locked closed isolation valve outside containment; or (2) One automatic isolation valve inside and one locked closed isolation valve outside containment; or (3)
One locked closed isolation valve inside and one automatic isolation valve outside containment; or (4) One automatic isolation valve inside and one automatic isolation valve outside containment.
The table indicates (1) if the systerms meet the isolation requirements identified; the types of valves~used, (2) if the capability for leak testing individual valves exists, (3) the high pressure low pressure interfaces, (4) method of pressure reduction in closed loop systems and (5) how the systems are isolated (by procedures or automatically).
Check valve orientation was included because there has been some recent concern that vertically mounted check.valves are not as effective as those mounted horizontally.
There was, however, no data in the FSARs on check valve orientation.
For isolation of the systems identified to meet current criteria, they must satisfy conditions in the appropriate SRPs GDC 55 and Section XI of the ASME Code. These documents establish the combinations of accept able valves, the testing interval, and the individual valve leak testing requirements.
OFFICE...
SURNAME.
DATE.
NRC FORM 318 (9-76) NRCM 0240
- U. S. GOVERNMENT PRINTING OFFICEt 1976 -
626-624
'Mr. James H. Drake
- 4 DEC 2 1 1978 To meet SEP schedule requirements, we need your verification of the correctness of the data presented in the enclosed table and all additional information you may have pertaining to Safety Topic V-11.A by January 29, 1979.
Sincerely, Dennis L. Ziemann, Chief Operating Reactors Branch #2 Division of Operating Reactors
Reference:
Memo: E. G. Case to R. F. Fraley, Executive Director ACRS, dated July 11, 1977.
Subject:
"Isolatibn of Low Pressure Systems from Reactor Coolant System".
Enclosure:
As stated cc w/enclosure:
See next page DISTRIBUTION NRC PDR Local PDR ORB #2 Reading NRR Reading VStello DGEisenhut OELD OI&E (3)
DLZiemann ABurger HSmith BGrimes TERA JRBuchanan ACRS (16)
DKDavis FFIcrE.
DOR:ORB #2 DOR:ORB #2 SURNAME-.ABurger:ah DLZiemann O ATER 2(96/
12/
78 0240 U. S GOVERNMENT 1
O I,9.2.
NRC FORM 318 (9-76) NRCM 0240
- u. s. GOVERNMENT PRINTING OFFICEs 1976 -
626.624
Mr. James H. Drake 5 -
December 21, 1978 cc Charles R. Kocher, Assistant General Counsel Southern California Edison Company Post Office Box 800 Rosemead, California 91770 David R. Pigott Samuel B. Casey Chickerihg & Gregory Three Embarcadero Center Twenty-Third Floor San Francisco, California 94111 David W. Gilman Robert G. Lacy San Diego Gas & Electric Company P. 0. Box 1831 San Diego, California 92112 Mission Viejo Branch Library 24851 Chrisanta Drive Mission Viejo, California 92676 U. S. Nuclear Regulatory Commission ATTN: Robert J. Pate Post Office Box 4167 San Clemente, California 92672
PLANT:
San Onofre Evaluation of Isolation of Low Pressure Systems From Reactor Coolant System I34 Meets Redundancy Testable Location of Method of Direct Interfaces Isolatiog of Type Between HP/LP Check Valve Pressure Method of Criteria Isolation Valves Valves Interface Orientation Reduction Isolation Remarks Water Cleanup System6 8
Inlet Yes IMO & 1 Inside containment NA Orifice OWG 568767 manual Discharge Yes IMO & 1 No Inside containment NA check (CV 304 & 5)
Seal Injection System ECCS Low Pressure No low pressure injection Injection system Accumulators1 No accumulators Sampling System Yes IMO & 1 No Inside contaiment?
NA Throttling 3 sampling systems -pressur manual valve izer liquid & steam space and reactor loop RHR System Suction Side Yes 2MO No Inside containment NA NA High pressure Single drop line interlock on inboard valves other valves administratively locked out Discharge Side Yes 2MD No Inside containment NA NA
NOTE:
- 1. PWRs only
- 2. BWRs only
- 3. Only direct interfaces considered--service water and component cooling water systems not evaluated
- 4. High pressure systems (i.e., control rod drive hydraulic, isolation condenser, standby liquid control, high pressure injection, & RCIC) connected to reactor coolant pressure boundary not evaluated
- 5. Inadvertent overpressurization of makeup tank due to reactor coolant pump seal leak off
- 6. Reactor water cleanup system for BWRs and CVCS or Letdown System for PWRS
- 7. Isolation requirements for ECCS specified in SRP 6.3 (Section III), for RHR system in BTP RSB 5-1 attached to SRP 5.4.7 and for water cleanup and sampling system in GDC 55
- 8. NA -
Not Applicable