ML18152B087
| ML18152B087 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 08/15/1988 |
| From: | Cruden D VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| 87-707C, NUDOCS 8808240183 | |
| Download: ML18152B087 (9) | |
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VIRGINIA ELECTRIC AND POWER COMPANY RICHMOND, VIRGINIA 23261 August 15, 1988 D.S.CRUDEN VICE PRESIDENT-NUCLEAR United States Nuclear Regulatory Commission Attention:
Document Control Desk Washington, D.C. 20555 Gentlemen:
VIRGINIA ELECTRIC AND POWER COMPANY SURRY POWER STATION UNITS 1 AND 2 Serial No.
NO/ETS:vlh Docket Nos.
License Nos.
CONTAINMENT PENETRATION EVALUATION SUPPLEMENTAL INFORMATION 87-707C 50-280 50-281 DPR-37 DPR-37 In a letter dated February 29, 1988 (Serial Number 87-707A), we submitted an evaluation that justified specific penetrations are normally operating and water filled under accident conditions. Therefore, these penetrations are not required to be vented and drained during Type A testing.
The evaluation consisted of a single failure analysis for the systems associated with the specific penetrations to demonstrate that water is supplied to the penetration under any credible single failure.
In subsequent phone calls, your staff requested additional information to complete the review of this matter. provides the additional technical information which includes a discussion of valve type, position and orientation and the water supply for each system.
As discussed in a telephone call on July 20, 1988, with Mr.
Frank Jape we intend to request an exemption from 10CFR50 Appendix J schedular requirements for Unit 2.
To resolve the technical issues addressed in NRC IR 86-36 we request you focus the attention of your review on penetration No. 46, RCS loop fill valve.
In recognition of the fact that a 30 day supply of water cannot be assured to maintain a water filled penetration, containment penetrations (56B, 560, 63, 64, 97b) should be deleted from our previous submittal dated February 29, 1988.
To help expedite your review of this issue, we will meet with your staff at their earliest convenience to discuss any additional concerns, e.g., system operations, operator actions, and applicable station procedures/drawings.
fl/JO I I l l
If.you have any questions, please call.
\\ V~~truly yours,
'JL~ ~'-'7------------
Attachment cc: U.S. Nuclear Regulatory Commission Region II 101 Marietta Street, N.W.
Suite 2900 Atlanta, Georgia 30323 Mr. W.E. Holland NRC Senior Resident Inspector Surry Power Station Mr. Chandu P. Patel NRC Surry Project Manager Project Directorate II-2 Division of Reactor Projects-I/II
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ATTACHMENT 1 ADDITIONAL INFORMATION FOR CONTAINMENT PENETRATIONS
I.. SAFETY INJECTION Provide information to show that for each credible single failure, water is supplied to each penetration.
COMPONENT
- 1.
Pump (injection phase)
- a.
Safety injection (charging)
- b.
Low-head safety injection
- 2.
Automatically operated valves (open on safety injection signal)
(injection phase)
- a.
Isolation valves at discharge of high head safety injection pumps (cold-leg injection)
- b.
Low-head safety injection pump discharge isolation valves (cold-leg injection)
- c.
Refueling water storage tank to charging pump return valves
- 3.
Valves automatically closed on safety injection signal
- a.
Charging line injection
- b.
Volume control tank discharge MALFUNCTION Fails to start Fails to start Fails to open Fa i1 s to open Fails to open Fails to close Fails to close COMMENTS Three provided.
Evaluation based on operation of one.
Two provided.
Evaluation based on operation of one.
One of two parallel valves is required to open.
One line from each pump leading to common discharge header.
Isolation valve in this line locked open Two in parallel; one out of two is assumed to open.
Two valves in series are provided wherever closure is required.
Two valves in series are provided wherever closure is required.
e SAFETY INJECTION (Cont 1d)
- 4.
Valves operated for recirculation
- a.
Containment Sump
- b.
Safety injection charging pump suction valve from low-head safety injection pump discharge
- c.
Isolation valve at suction header of low-head safety injection pump from refueling water storage tank
- d.
Isolation valves suction to high-head safety injection pumps
- e.
Isolation valves on the low-head safety injection system minimum flow or a test line returning to the refueling water storage tank
- f. Suction and discharge valve on safety injection charging pump Fails to open Fails to open Fails to close*
Fails to close Fails to close Fails to close Two lines in parallel; one valve in either line is required to open.
One recirculation line from each low-head pump.
One motor-operated valve in each line, one of which must open.
Motor-operated valve and check valve in series.
Motor-operated valve required to close backed up by check valve.
Two motor-operated valves in parallel, backed up by check valve and admin-istratively controlled, normally open manual gate valve.
Two motor-operated valves in each minimum flow line in series with a check valve in each line.
All are normally open.
Failure of one to close does not prevent separate and redundant recir-culation paths.
e SAfETY INJECTION (Cont'd)
Demonstrate that water is available at greater than I.I Pa.
the discussion the source of the water for 30 days.
Include in NORMAL OPERATING NORMAL OPERATING COMPONENT FUNCTION ARRANGEMENT Refueling Storage Lined up to water storage tank for suction of high tank refueling head safety injection, lowhead safety injection, and containment spray pumps High head Charging to Take suction from safety in-the RCS volume control jection pumps tank and dis-charge to normal charging connections Low-head None Lined up to take safety in-suction from re-jection pumps fueling water storage tank and discharge to reactor coolant piping ACCIDENT FUNCTION Source of borated water for core and contain-ment cooling spray pumps Supply borated water to core Supply borated water to core ACCIDENT ARRANGEMENT Lined up to suction of high-head safety in-jection
- charging, low-head safety in-jection, and containment spray pumps Initially 1 i ned up to take suction from refueling water storage tank and discharge to hot and cold legs of reactor coolant piping; Lined up to take suction from the con-tainment sump during the recirc. phase if required.
In it i a 11 y 1 i ned up to suction from refueling water storage tank and dis-charge to reactor coolant piping; Lined up to take suction from the containment sump during the recirc. phase if required.
L_
SAFETY INJECTION (Cont'd)
As stated in the previous response dated February 29, 1988, Surry Unit 1 and Unit 2 are each designed with an accident mitigating system to ensure the containment will be cooled and depressurized to subatmospheric pressure in less than 60 minutes following the design-basis accident (ref. Surry 1 & 2 UFSAR 6.3.1).
After the first hour of the design basis accident, any penetration leakage is directed into containment while recirculation subsystems maintain a subatmospheric pressure condition.
The subject containment pipe penetrations are connected with inside pipe configurations installed with pipe loops where water is trapped to block any air in leakage through a faulted penetration.
A single-active-failure analysis is presented.
All credible active system failures are considered.
The analysis of the LOCA presented in our UFSAR is consistent with the single-failure analysis.
The analysis is based on the worst single failure (generally a pump failure) in the safety injection system.
The analysis shows that the failure of any single active component does not prevent fulfilling the design function; also, operator action is not required to correct the malfunction.
The source or quantity of water to the penetration is a concern when the penetration is supporting accident mitigation.
After the first hour open penetrations in Safety Injection and Recirculation Spray are a part of closed piping systems operating to recirculate the contents of the containment sump.
Water is available to the subject penetrations at greater than 1.1 Pa during the first sixty (60) minutes of a OBA because the systems are in service performing their accident mitigating design functions.
At sixty (60) minutes the containment structure is at subatmospheric pressure.
Depending upon the direction of the appropriate emergency response procedure, water can be made available to the penetrations during the subsequent 30 day period. A review of emergency procedures specific to the Large Break LOCA Design Basis Accident indicates that HHSI remains operating for the duration of the event.
e SAFETY INJECTION (Cont'd)
Describe the isolation valves at each penetration.
Include valve orientation, packing, and possible leakage path.
PENETRATIONS VALVES TYPE 7
15 21 23 46 60 61 62 68,69 113 1{2)-SI-150 3/4 11 Rockwell Edwards (Globe)
MOV-1867C&D 3
11 Darling {Split wedge)
MOV-2867C&D 3
11 Darling {Split wedge) 1(2)-CH-309 3 11 Velan (Disc Check)
MOV-1289A 3
11 Darling {Split wedge)
MOV-2289A 3
11 Darling {Split wedge)
MOV-1842 MOV-2842 MOV-18698 MOV-28698 FCV-1160 FCV-2160 MOV-1890A MOV-2890C MOV-1890C MOV-2890C MOV-1890C MOV-28908 3
11 Darling {Split wedge) 3 11 Darling (Split wedge) 3 11 Darling (Split wedge) 3 11 Darling {Split wedge) 2 11 Copes Vulcan (Plug) 2 11 Copes Vulcan (Plug) 10 11 Darling (Split disc) 10 11 Darling (Split disc) 10 11 Darling (Split disc) 10 11 Darling (Split disc) 10 11 Darling (Split disc) 10 11 Darling (Split disc)
MOV-1860A&B 12 11 Aloyco (Split disc)
MOV-2860A&B 12 11 Aloyco (Split disc) l-SI-174 2-SI-174 MOV-1869A MOV-2869A 3/4 11 Velan (Globe) 3/4 11 Rockwell Edwards 3
11 Velan (Split disc) 3 11 Velan (Split disc)
- PACKING Exposed to Pa Exposed to Pa Exposed to Pa Not Exposed to Pa Exposed to Pa Exposed to Pa Exposed to Pa Exposed to Pa Exposed to Pa Exposed to Pa Exposed to Pa Exposed to Pa Exposed to Pa Exposed to Pa Exposed to Pa Exposed to Pa Exposed to Pa Exposed to Pa Exposed to Pa Exposed to Pa Not Exposed to Pa Not Exposed to Pa Exposed to Pa Exposed to Pa
- Packing could be exposed to the containment atmosphere at accident pressure if the lines were not water filled.
- However, as discussed above and in our previous response dated February 29, 1988 these penetrations are normally filled with water and the packing would not be exposed to containment atmosphere.
Note:
Type 11C 11 Testing will be performed for each penetration with all identified leaks noted and corrected prior to the 11 As Left" but no Type 11C 11 penalties will be added to the Type A results.
e II. OUTSIDE RECIRC SPRAY SYSTEM Provide information to show that for each credible single failure, water is supplied to each penetration.
To ensure that adequate NPSH for the outside recirculation spray pumps exists at their operating point during design-basis accident, the sump water at the pump suction inlet has added provisions for subcooling.
The subcooling is achieved by routing cold refueling water storage tank inventory at 45 F into the containment sump via two bleedlines, one from each containment spray pump discharge line inside the containment.
Each bleedline contains a restricting orifice to balance the flow with the remainder of the containment spray system.
A 12-in. line provides a cross connection between the two 12-in. lines from the reactor containment sump to the suction of the outside recirculation spray pumps.
Each of the two 12-in. lines from the sump has its suction opening located in one of the equal sections of the sump; these sections are formed by the screen assembly that surrounds the reactor containment sump.
The probability of screen clogging is remote.
However, if the first-stage or the second-stage screens of one of the suction points did become clogged so that no water could be supplied to a pump suction, the cross-connecting line would supply water to that pump from the other section of the sump through the other 12-in. suction line.
Demonstrate that water is available at greater.than 1.1 Pa.
Include in the discussion the source of the water for 30 days.
After the Recirc Spray is initiated, the system is allowed to run until containment pressure is subatmospheric.
As the time after the LOCA increases, the energy released to the containment decreases and the rate of increase in containment pressure significantly decreases.
After a period of time, one RS pump provides sufficient spray to maintain the containment subatmospheric.
Containment Sump water is available at greater than 1.1 Pa and is the source of water for this penetration for 30 days.
Describe the isolation valves at each penetration.
orientation, packing and possible leakage path.
PENETRATIONS 66,67 VALVES MOV-RS-155A&B MOV-RS-255A&B TYPE 12"-Tufline Plug 12" Tufline Plug Include valve
- PACKING Exposed to Pa Exposed to Pa
- Each valve is normally open but receives an open signal upon initiation of a CLS to ensure its open status. Packing could be exposed to the containment atmosphere at accident pressure if the lines were not water filled.
- However, as discussed above and in our previous response dated February 29, 1988 these penetrations are normally filled with water and the packing would not be exposed to containment atmosphere.
NOTE:
Type "C"
testing will be performed for each penetration with all identified leaks noted and corrected prior to the 11As Left" but no Type "C"
penalties will be added to the type A results.