ML19259A639
| ML19259A639 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 12/21/1978 |
| From: | Ziemann D Office of Nuclear Reactor Regulation |
| To: | Groce R YANKEE ATOMIC ELECTRIC CO. |
| References | |
| TASK-05-11.A, TASK-5-11.A, TASK-RR NUDOCS 7901080360 | |
| Download: ML19259A639 (7) | |
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4, UNITED STATES 4
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'S NUCLEAR REGULATORY COMMISslON
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.j WASHINGTON, D. C. 20555
,8, December 21, 1 978 4s..*
Docket No. 50-29 Mr. Robert H. Groce Licensing Engineer Yankee Atomic Electric Company 20 Turnpike Road Westboro, Massachusetts 01581
Dear Mr. Groce:
RE: VERIFICATION OF PLANT INFORMATION ON SEP TOPIC V-ll.A,
" REQUIREMENTS FOR ISOLATION OF HIGH AND LOW PRESSURE SYSTEMS" Our initial review of SEP Safety Topic V-ll.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 wate" or component cooling through a heat exchanger) were not considt A.
Systems designed to operate at high pressure were also not included (i.e., BWR isolation condenser) except for the high pressure RHR system on several BWRs, which were included for completeness.
For PWRs the seat 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 inadverte'.cly overpressurize the water rrkeup tank.
For BWRs the reactor versel head spray cooling system vn included because the potential for overpressurizing the condensate storig tank, if not properly vented, may exis'..
730108o % e
Mr. Robert H. Groce December 21, 1 978 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 nomally 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 pemit periodic testing of the check valves for leak tightness and the testing is perfomed at least annually.
The isolation requirements for the RHR system as stated in Branch Technical Position BTP-RSB 5-1 are listed below:
(1) The following shall be provided in the suction side of the RHR system te isolate it from the RCS.
(a) Isolation shall be provided by at least two power-operated valves in series. The valve pos :fons 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 nomally 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 function, the power-operated valve is to be opened upon receipt of a safety injection signal once the reactor coolant pressure has decreased,
Mr. Robert H. Groce December 21, 1978 (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 outsiae containment.
The table indicates (1) if the systems 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 tt'se 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, CDC 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.
Mr. Robert H. Groce December 21, 1 978 To meet SEP schedule requirene*;, 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, ti yn.,,'u /%
LEA % '*
Dennis L. Ziema', 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:
" Isolation of Low Pressure Systems from Reactor Coolant System".
Enclosure:
As stated cc w/ enclosure:
See next page
fir. Robert H. Groce
- 5 December 21, 1 978 CC Mr. Lawrence E. Minnick, President Yankee Atomic Electric Company 20 Turnpike Road Westboro, Massachusetts 01581 Greefield Community College 1 College Drive Greenfield, Massachusetts 01301 1
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PLANT: Yankee Rowe Evaluatto.. of Isolaticn of Low Irassure Systras From Reactor Coolant System Meets Redundancy Testable Locat un of Method of Direct Interfaces *4 Isolatio9 of Type Between HP/LP Check Valve Pressure Method of 3
Criteria Isolation Valv i, Valves Interface Orientation Reduction isolation Remarks 6
Water Cleanup System Inlet Demineralizer make-up water system DWG & description does not specifically iden-Lify HP/LP interface Discharge Seal Injection System,5 1
0 tow Pressure Yes (see 3 check No At least one outside NA NA Accumulator and low pressure Injection remarks) and one inside injection system share common y
Accamiulators contilnment line. Three check valves (although Fig. 6.3-1 only shows two) one recently Installed (1977) per project manager Sampling System No information provided in FSAR AHA System Suction Side Yes 2M0 No inside containment NA NA Administrative.
Fig. 5.5-1 $1ngle drop line SC-Mov both valves key 552 & 554 locked closed J
common key all 4 valves (suction and discharge)
(No auto closure Discharge Side Yes 2M0 No Inside containment NA NA or open permissive SC-MOV interlock) 551 & 553 4
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a NOTE:
- 1. PWRs only
- 2. BWRs on1y
- 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 eva1uated
- 5. Inadvertent overpressurization of maneup tank due to reactor coolant pump seal leak off
- 6. Reactor water cleanup system for BWRs and CVCS or Letdown System for PWR5
- 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 sar.pling system in GDC 55
- 8. NA - Not Applicable 9
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