ML17192A933
| ML17192A933 | |
| Person / Time | |
|---|---|
| Site: | Dresden, Quad Cities  |
| Issue date: | 08/12/1980 |
| From: | Crutchfield D Office of Nuclear Reactor Regulation |
| To: | Peoples D COMMONWEALTH EDISON CO. |
| Shared Package | |
| ML17192A934 | List: |
| References | |
| TASK-06-04, TASK-6-4, TASK-RR NUDOCS 8009020456 | |
| Download: ML17192A933 (25) | |
Text
e*
.*~'"-*.......
. ~~IBUTION:.
c,.AroCK et S ( 5).
RTedesco JHeltemes
- PPolk ACRS ( 16 }_,,',..,,,,
AUGUST
,Docket Nos.
50-10.~------2=37:;-,-~
50-249, 50-254
& 50-265 Mr. o. Louis Peoples' *
- O i rector of Nuclear l1cens1 ng Co111nonwea 1th Edi son Corrpany Post Office Box 767 Chicago, 1111no1s 60690
Dear Mr. Peoples:
1 2 1980 "NRCPD1t(5)
Local PDR (5)
TERA (5)
NS.IC NRR Reading ORB #5 Reading ORB #2 Reading DEisenhut JOlshinski RPurple TNovak Tlppol ito RBevan SNorris DCrutchfield PO'Connor HSmith Gray File (5)
Xtra Cy (6)
DELO.
DIE (3)
- By letter dated February 23*. 1980, you were requested to provide
- information regarding primary coolant system pressure isolation valves.
The objective of this 10 CFR 50.54(f) letter was to 1dent1fy those plants which have either or both of the valve configurations found 1n WASH-1400
- (Event V) to be s1gn1f1cant risk contributors to an 1ntersystem LOCA which results 1n *a core melt accident~
We have confirmed that the two spec1f1c Event V valve conf1gurat1ons do not exist at your f ac11it 1es.
This is based upon the e~a luat ion of your.
response to our February letter as well as the review of previously docketed 1nforri~tion (Enclosure).
Based on this. -0ur activities regarding these valve.configurations have been finalized for your facilities.
In addition to these Event V valve configurations, we are continuing
- our efforts to review other configurations located at high pressure/
-1ow pressure system boundaries for their potential risk contribution *
. to an intersystem LOCA which may result 1n a core melt accident.
Therefore, further activity regarding the broader topic of intersystem LOCA's may be expected in the future *.. * ::
Your time and effort 1n clos1ng out the Event V portion *of the inter-system LOCA concern are appreciated.
Sincerely,
. prig;**'j1;'! by.
t} ~
ii!~cde't:~hie~. *. *. *
.. *.. ::~.. *::***-
- ~,
Operating Reactors Branch 115 v s1on of L 1cens1ng
....,- ~*
OFFICE~ *. OL :.ORB. #.5/ P.M. D ; O.RB.. #2/P.M.. DL: ORB. #.2/P.~ DL; PO 1 Connor: rj RBevan*
PPo 1 k rutch fie 1 d * * **,.~: * --'.... ::.:::.; * *...
- *- *~....,. " -.
SURNAME
.. 8 *
- r1* 7ao* * * * * **t l.i'i!Bo**** *.o.1i( 1arr * * * * *i "ljifaa* * * * * * * ** * *** ** ** *.,. * * * * * * * * **- * * * * * * * * *
- DATE~.......... \\.....-...,.... *.;.. : *.* '.......,...... **:..................................*....., *.....,...................
NRC'FORM 318 (9*7GJ NRCM 0240
"*'"***,*.~-.. -. -*,.,,.. *
- u.s. GOV,ERNMENT PRINTING OFFICE: 19l9'289*369.
-~.
UNITED ST ATES NUCLEAR REGULATORY COMMISSION W~SHIN.GTON, D. C. 20555 Mr. o. Louis Peo~les.
Director of Nuclear Licensing Conmonwea 1th Edi son Conpany.*
Post Office Box 767.*
Chi._cago, I 11 i noi s 60690
~.'. '.
Dear Mr. Peoples:
August 12, 1980 By letter dated February 23, 1980~ you were ~eqliested to provide inforlllcltion regarding primary coolant system pressure isolation valves~
The objective. of this 10 CFR 50.54(f) letter was to identify those plants which have either or both of the valve configurations found in WASH-1400 (Event V) to be significant risk contributors to ah int~rsystem LOCA which results 1.n a core melt. accident.*
We have confirmed *that -th~ two specific tvenf V valve configurations do not exist at ypur faciiities> This is based upon.the evaluation of your response to our February letter as ~elf as *the*review of previot,Jsiy docketed informat'ion (EnclOsure). 'Based Ori this, our activities regarding these valve configurations have been finalized for your fatilities.
In addition to these E.vent V *valve configuration.s, we are cont.inui:ng ou.t: efforts to review other cohf i gurat i ans located at _high pressure/,*
low pressure system boundaries for their :potential risk contribution to an i ntersysteni LOCA which may result i'n 'a core melt acti dent*.
Therefore~ further activity regarding the.broader topic.of. i ntersystem LOCA 1 s may be expected in, ttie future.*
Your time.and effort in closing.out the Event V portion of the. inter-system LOCA concern are appreciated.
Enclosure and c.cs:
See next page Sincerely,
/')
- '/ 1
- .i.---
. /J //:
- /' 1./ d. C.*C-17;-
~ *I,*;:,a l_..,~..
. '. Jjv'DeMis Iii~. Crutchfield, Chief J
Dp~rating React6rs Branch. #5 Diviii6n 6f Lic~nsing
. I.
... ~
Mr. o. Louis Peoples
Enclosure:
Franklin Research Center Technical Evaluation Report, "Primary Coolant System Pressure Isolation Valves,"
dated July 21~ 1980.
cc w/encl osure:
See next page
"". 2 -
August 12, 1980
. *~..
Mr. D. Louis People~ cc
- w/ enclosure:
Isham, Lincoln & Beale Counselors at Law One First National Plaza, 42nd Floor Chicago, Illinois 60603 Mr. B. B.
Stephenso~
Plant Superintendent*
Dresden Nuclear Power Station Rural Route #1 Morris, Illinois 60450 Natural Resources Defense Counci 1 917 15th Street, N. w.
Washington, D. c.
20005
- u. s. Nuclear Regulatory Co11111ission Resident Inspectors Office Dresden Station RR #1 Morris, Illinois 60450 Susan N. Sekuler Assistant Attorney General Environmental Control Division 188 w. Randolph Street Suite 2315 Chicago, Illinois 60601 Morris Public Library 604 Liberty Street Morris, Illinois 60451 Chairman Board of Supervisors of Grundy County
- Grundy County Courthouse' Morris, Illinois 60450 August 12, 1980 Department of Public Health ATTN:
Chief, Division of Nu cl ear Safety 535 West Jefferson Springfield, Illinois 62761 Director, Technical Assessment Divisi~n Office of Radiation Programs (AW-459)
U. s. En vi ronmenta 1 Protection Agency Crystal.Mall #2 Arlington, Virginia 20460
- u. s. Environmental Protection Agency Federal Activities Branch Region V Office ATTN:
EIS COORDINATOR 230 South Dearborn Street Chicago, Illinois 60604 Resident Inspector Dresden Nuclear Power Station c/o U. S. NRC Rura 1 Route #1 Morris, Illinois 60450
TECHNICAL EVALUATION REPORT PRIMARY COOLANT SYSTEM PRESSURE ISOLATION VALVES COMMONWEALTH EDISON COMPANY DRESDEN UNIT 1 NRCDOCKETNO.50-010 NRCTACNO.
12913 NRG CONTRACT NO. NRC-03-79-118 Prepared by Franklin Research Center
. The Parkway at Twentieth Street Philadelphia, PA 19103 Prepared for Nuclear Regulatory Commission Washington, D.C. 20555 FRC PROJECT C5257 FRC TASK 21~6 Author:
P. N. Noell/T. c. Stilwell FRC Group Leader: P. N. Noell Lead NRC Engin(=Jer:
P. J. ?ollr.
July 21, 1980 This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, or any of their employees, makes any warranty, expressed or implied, or assumes any legal liability or responsibility for any third party's use. or the results of such use, of any information, apparatus, product or process disclosed in this report, or rep;esents that its use by such third party would not infringe privately owned rights.
-e~nklin Research Center A Division of The Franklin Institute The Ber,jarr:in FrimkJ,n F'11:k1*.. a7. Phi la. Pa. 191 OJ (215) 448* I OOC
1.0 INTRODUCTION
The NRC staff has determined that certain isolation valve configurations in systems connecting the high-pressure Primary Coolant System (PCS) to lower-pressure systems extending outside containment are potentially significant contributors to an intersystem loss-of-coolant accident (LOCA).
Such configu-rations have been found to represent a significant factor in the risk computed for core melt accidents.
The sequence of events leading to the core melt is initiated by the failure of two in-series check valves to function as a pres-sure isolation barrier between the high-pressure PCS and a lower-pressure system extending beyond containment.
This causes an overpressurization and rupture of the low-pressure system, which results in a LOCA that bypasses con-tainment.
The NRC has determined that the probability of failure of these check valves as a pressure isolation barrier can be significantly reduced, if the pressure at each valve is continuously monitored, or if each valve is periodi-cally inspected by leakage testing, ultrasonic examination, or radiographic inspection.
NRC has. established a program to provide increased *assurance that such multiple isolation b*rriers are in place in all operating Light Water Reactor plants designated DOR Generic Implementation Activity B-45.
In a generic letter of February 23, 1980, the NRC requested all licensees to identify the following valve configurations which may exist in any of their plant systems cormnunicating with the PCS: 1) two check valves in series or 2) two check valves in series with a motor-operated valve (MOV).
For plants in which valve co~figurations of concern were found to exist, licensees were further requested to indicate: 1) whether, to ensure integrity, continuous surveillance or periodic testing was currently being conducted, 2) whether any valves of concern were known to lack integrity, and 3) wheth~r plant proce-dures should be revised or plant modifications be made to increase reliability.
Franklin Research Center (FRC) was requested by the NRC to.provide tech-nical assistance to NRC's B-45 activity by reviewing each licensee's s~mittal against criteria provided by the NRC and verifying the licensee's reported findings from plant system drawings.
This report documents FRC's technical review.
2.0 CRITERIA 2.1 Identification Criteria For a piping system to have a valve configuration of concern, the follow-ing five items must be fulfilled:
- 1)
'nae high-pressure system must be connected to the Primary Coolant System;
- 2) there must be a high-pressure/low-pressure interface present in the line; 3). this same piping must eventually lead* outside containment;
- 4) the line must have one of the valve configurations shown in Figure l; and
- 5) the pipe line must have a diameter greater than 1-inch *.
H P......----t---"1*~ l P Figure 1.
Valve Configurations Designated by NRC to b~ Included in This Technical Evaluation
-'}-
..... ~ *,
3.0 TECHNICAL EVALUATION
FRC has reviewed the response [Ref. 2] of the Commonwealth Edison Company (CWE) to NRC's generic letter [Ref. l] concerning the issue of PCS pressure isolation valve configurations for Dresden Plant Unit 1.
The licensee stated that none of their piping systems have any of the valve configurations of concern, as descr~ed by the identification criteria.
FRC independently checked the plant Piping and Instrumentation Diagrams (P&IDs) [Ref. 3] for piping systems that might have these valve configura-tions.
In this review of the licensee's response against the P&IDs and the identification criteria, FRC found no valve configurations of concern, thus verifying CWE's findings.
4.0 CONCLUSION
S In CWE's Dresden Plant Unit 1, all piping systems larger than 1-inch diameter that are interconnected to the PCS are free of the valve configura-tions of concern.
Therefore, no futher modifications to this plant's Techni-cal Specifications are necessary on this account.
- 5. 0 REFERENCES
[l].
Generic NRC letter, dated 2/23/80, from Mr. D *. G. Eisenhut, Department of Operating Reactors (DOR), to Mr. W. F. Naughton, Commonwealth Edison Company (CWE).
[2].
Commonwealth Edison Company's response to the generic NRC letter, dated 3/14/80, from Mr. W. F. Naughton (CWE) to Mr. D. G. Eisenhut (DOR).
[3].
List.of examined P&IDs:
Bechtel Drawing:
104R210 104R212 (Rev. 6)
(Rev. 6)
Sargent & Lundy Drawing:
M-594 M-595 General Electric Drawing:
7368E83 7368E84 (Rev. 10)
(Rev. 13)
TECHNICAL EVALUATION REPORT PRIMARY COOLANT SYSTEM PRESSURE ISOLATION VALVES COMMONWEALTH EDISON COMPANY DRESDEN UNIT 2 NRC DOCKET NO. 50-237 NRCTACNO.
12914 NRC CONTRACT NO. NRC-03-79-118 Prepared by Franklin Research Center The Parkway at Twentieth Street Philadelphia, PA 19103 Prepared for
- Nuclear Regulatory Commission Washington, D.C. 20555 FRC PROJECT C5257 FRC TASK 24 7 Author:
P. N. Noell/T. C. Stilwell FRC Group Leader: P. N. Noell Lead NRG Engineer: P. J. i.'olk July 21, 1980 This report was prepared as an account of work sponsored by an agency of the United States Government Neither the Unitea States Government nor any agency thereof, or any of their employees.
makes any wa~ranty, expressed or implied, or assumes any legal liability or responsibility for any third party's use, or the results of such use, of any information, apparatus, product or process disclosed in this report, or represents that its use by such third party would not infringe privateiy owned rights.
""'((f'i:{fr;nklin Research Center A Division of The FrankJin Institute The ~njamin Franklin Parkway. Phil11.. Pa I 9103 (215) 448* I 000
1.0 INTRODUCTION
'nle NRC staff has determined that certain isolation valve configurations in systems connecting the high-pressure Primary Coolant System (PCS) to lower-pressure systems extending outside containment are potentially significant contributors to an intersystem loss-of-coolant accident (LOCA).
Such configu-rations have been found to represent a significant factor in the risk computed for core melt accidents.
The sequence of events leading to the core melt is initiated by the failure of* two in-series check valves to function as a pres-sure isolation barrier between the high-pressure PCS and a lower-pressure system extending beyond containment.
This causes an overpressurization and rupture of the low-pressure system, which results in a LOCA that bypasses con-tainment.
The NRC has determined that the probability of failure of these check valves as a pressure isolation barrier can be significantly reduced, if the pressure at each valve is continuously monitered, or if each valve is periodi-cally inspected by leakage testing,, ultrasonic examination, or radiographic inspection.
NRC has established a proiram te provide increased assurance that such multiple isolation barriers are in place.in all operating Light Water Reactor plants designated DOR Generic Implementation Activity B-45.
In a generic letter of February 23, 1'80, the NRC requested all licensees to identify the following valve configurations which may exist in any of theit*
plant systems conununicating with the PCS: 1) two check valves in series or 2) two check valves in series with a motor-operated valve (MOV).
For plants in which valve configurations of concern were found to exist, licensees were further requested to indicate: 1) whether, to ensure integrity, continuous surveillance or periodic testing was currently being conducted, 2) whether any valves of concern were known to lack integrity, and 3) whether plant proce-dures should be revised*or plant modifications be made to increase reliability.
Franklin Research Center (FRC) was requested by the NRC to provide tech-nical assistance to NRC's B-45 activ1ty by reviewing each licensee's submittal against criteria provided by the NRC and verifying the licensee's reported findings from plant system drawings.
This report documents FRC's technical review.
2.O CRITERIA 2.1 Identification Criteria For a piping system to have a valve configuration of concern. the follow-ing five items must be fulfilled:
- 1)
The high-pressure system must be connected to the Primary Coolant System;
- 2) there must be a high-pressure/low-pressure interface present in
.the line;
- 3) this same piping must eventually lead outside containment;
- 4) the line ml.ist have one of the valve configurations shown in Figure l; and
- 5) the pipe line must have a diameter greater than 1-inch.
I
~
~
~
v1 I
HP4 I
., LP Figure l.
Valve Configurations Designated by NRC to be Included in This Technical Evaluation
'I*'
3.0 TECHNICAL EVALUATION
FRC has reviewed the response [Ref. 2] of the Counnonwealth Edison Company (CWE) to NRC's generic letter [Ref *. l] concerning the issue of PCS pressure.
isolation valve configurations for Dresden Station Unit 2.
The licensee stated that none of their piping ~ystems have any of the valve c~nfigurations of concern., as described by the identification criteria.
FRCindependently checked the plant Piping and.Instrumentation Diagrams (P&IDs) [ReL 3] for piping systems that might have 'these valve configura-tions.
In this review of the licensee's response against the P&IDs and the identification ~riteria, FRC found no valve configuiation~ of concern, thus verifying CWE's findings.
4.0 CONCLUSION
S In CWE's Dresden Station Unit 2, all piping systems larger than 1-inch diameter that are interconnected to the P:CS are free of the valve configura-tions of concern.
Therefore, no futher modifications* to this plant's Techni-
- cal Specifications are necessary on this account *
- 5. 0 REFERENCEf;
[l].
Generic NRC letter, dated. ~/23/80, from Mr. D. G. Eisenhut, Department.
of Operating Reactors (DOR), to Mr *. *w. F. Naughton,. Commonwealth Edison (CWE).
[2].
Commonwealth Edison's re~ponse to the* generic,NRC letter, dated 3/14/80, from Mr. W.
F~. Naughton (CWE) to Mr. D. G. Eisenhut* (DOR) *
. [3].
List of examined P&IDs:
- Sargent &.Lundy Drawing:
M-11 (Rev. C). Sh. 2 M-26.
(Rev. AA)*. Sh. 1 of 2
'M":-io (Rev. Y)
Sh. 2 of 2 M-27 (Rev. EE)
M-28 (Rev. V)
M-29 (Rev. MM).
M-30 (Rev. BB)
-3.-:.
M-32 (Rev. V)
M-33 (Rev. W)
M-48 M-51 (Rev. FF)
).......
TECHNICAL EVALUATION REPORT PRIMARY COOLANT SYSTEM PRESSURE ISOLATION VALVES COMMONWEALTH EDISON COMPANY DRESDEN UNIT 3 NRC DOCKET NO. 50-249 NRC TAC NO.
12897 NRC CONTRACT NO. NRC-03-79-118 Prepared by Franklin Research Center
. The Parkway at Twentieth Street Philadelphia, PA 19103 Prepared for Nuclear Regulatory Commission Washington, D.C. 20555 FAG PROJECT C5257 FRC TASK 231 Author:
P. N. Noell/T. C. Stilwell FRCGroupLeader: P. N. Noell Lead NRC Engineer: P. J. Polk July 21, 19.80 This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, or any ot their employees.
makes any warranty, expressed or implied. or assumes any legal liability or respon~ibility for any third party's use. or the results of such use, of any information, apparatus, product or process disclosed in this report, or represents that its use by such third party would notinfringe privately owned rights.
~nklin Research Center A Division of The Franklin Institute The Bt-njemin Franklin Parkway. Philll.. Pe. 19103 (21~1448 1000
-~,
i..
I,.
1.0 INTRODUCTION
The NRC staff has determined that certain isolation valve configurations in systems connecting the high-pressure Primary Coolant System (PCS) to lower-pressure systems extending outside containment are potentially significant contributors to an intersystem loss-of-coolant accident (LOCA).
Such configu-rations have been found to represent a significant factor in the risk computed for core melt accidents.
The sequence of events leading to the core melt is initiated by the failure of two in-series check valves to function as a pres-sure isolation barrier between the high-pressure PCS and a lower-pressure system extending beyond containment.
llais causes an overpressurization and rupture of the low-pressure system, whii;:h results in a LOCA that bypasses con-tainment.
The NRC has determined that the probability of failure of these check valves as a pressure isolation barrier can be significantly reduced, if the pressure at each valve is continuously monitored, or if each valve is periodi-cally inspected by leakage testing, ultrasonic examination, or radiographic inspection.
NRC has established a program to provide increased assurance that such multiple isolation barriers are in place in all operating Light Water Reactor plants designated DOR Generic Implementation Activity B-45.
In a generic letter of February 23, 1980, the NRC requested all licensees to identify the following valve configurations which may exist in any of their plant systems conununicating with the PCS: 1) two check valves in series or 2) two check valves in series with a motor-operated valve (MOV).
For plants 1n which valve configurations of concern were found to exist, licensees were further requested to indicate: 1) whether; to ensure integrity, continuous surveillance or periodic testing was currently being conducted, 2) whether any valves of concern*were known to lack integrity, and 3) whether plant proce-dures should be revised or plant modifications be made to increase reliability.
Franklin Research Center (FRC) was requested by the NRC to provide tech-nical assistance to NRC's B-45 activity by reviewing each licensee's submittal against criteria provided by the NRC and verifying the licensee's reported findings from plant system drawings.
llais report documents FRC's technical review.
i~
2.0 CRITERIA 2.1 Identification Criteria For a piping system to have a valve configuration of concern, the follow-ing five items must be fulfilled:
- 1)
The high-pressure system must be connected to the Primary Coolant System;
- 2) there must be a high-pressure/low-pressure interface present in the line;
- 3) this same piping must eventually lead outside containment;
- 4) the line must have one of the valve configurations shown in Figure i; and
- 5) the pipe line must have a diameter greater than 1-inch.
pc s 4-------1 I
H P..
- 1----~---t.-~ LP Figure l.
Valve Configurations De~ignated by NRC to hr Included in This Technical Evaluation
-'}-
I
-~*
- i.
i.
I..
- 3.~ TECHNICAL EVALUATION FRC has reviewed the response [Ref. 2] of the Commonwealth Edison Company (CWE) to NRC's generic letter [Ref. l] concerning the issue of PCS pressure isolation valve configurations for Dresden Station Unit 3.
'!be licensee stated that none of their piping systems have any of the valve configurations of concern, as described by the identification criteria.
FRC independently checked the plant Piping and Instrumentation Diagrams (P&IDs) [Ref. 3] for piping systems that might have these valve configura-tions.
In this review of the licensee's response against the P&IDs and the identification criteria, FRC found no valve configurations of concern, thus verifying CWE's findings.
4.0 CONCLUSION
S In CWE's Dresden Station Unit 3, all piping systems larger than 1-inch diameter that are interconnected to the PCS are free of the valve configura-tions of concern.
'lberefore, no futher modifications to this plant Is Techni-cal Specifications are necessary on this account.
5.0 REFERENCES
[l]. Generic NRC letter, dated 2/23/80, from Mr. D. G. Eisenhut, Department of Operating Reactors (DOR), to Mr. w. F. Naughton, Commonwealth Edison (CWE).
[2].
Commonwealth Edison's response to the generic NRC letter, dated 3/14/80, from Mr. W. F. Naughton (CWE) to Mr. D. G. Eisenhut (DOR).
[3].
List of examined P&IDs:
Sargent & Lundy Drawing:
M-357 (Rev. R)
Sh. 1 of 2 M-364 (Rev. M)
M-357 (Rev. R)
Sh. 2 of 2 M-372 (Rev. J)
M-358 (Rev. T)
M-374 (Rev. T)
M-359 (Rev. N)
- M-360 (Rev. Y)
M-361 (Rev. U)
M-363 (Rev. L)
i ! '.
I*.;
I,:
I:'
i.
- i.
i ' :-..
- '7:
TECHNICAL EVALUATION REPORT PRIMARY COOLANT SYSTEM PRESSURE ISOLATION VALVES COMMONWEALTH EDISON COMPANY QUAD CITIES UNIT 1 NAC DOCKET NO. 50-254 NACTAC NO.
12908 NAC CONTRACT NO. NRC-03-79-118 Prepared by Franklin Research Center The Parkway at Twentieth Street Philadelphia, PA 19103 Prepared for Nuclear Regulatory Commission Washington, D.C. 20555 FRC PROJECT C5257 FRCTASK 241 Author:
P. N. Noell/T. c. Stilwell FRC Group Leader: P. N. Noell Lead NRC Engineer:
P. J. Polk July 21, 1980 This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, or any of their employees, makes any warranty, expressed or implied, or assumes any legal liability or responsibility for any third party's use, or the results of such. use, of any information, apparatus, product or process disclosed in this report, or represents that its L'Se by such third party would not infringe privately owned rights.
~nklin Research Center A Division of The Franklin Institute The Benjamin Franklin Porkwny, Phila.. Pa. 19103 (215) 448-1000
I.
C'ft
[
i:
~:.. '.'
."..J*
1.0 INTRODUCTION
The NRC staff has determined that certain isolation valve configurations in systems connecting the high-pressure Primary Coolant System (PCS) to lower-pressure systems extending outside containment are potentially significant contributors to an intersystem loss-of-coolant accident (LOCA).
Such configu-rations have been found to represent a significant factor in the risk computed for core melt accidents.
The sequence of events leading to the core melt is initiated by the failure of two in-series check valves to function as a pres-sure isolation barrier between the high-pressure PCS and a lower-pressure system extending beyond containcient.
This causes an overpressurization and rupture of the low-pressure system, which results in' a LOCA that bypasses con-tainment.
The NRC has determined that the probability of failure of these check valves as a pressure isol~tion barrier can be significantly reduced, if the pressure at each valve is continuously monitored, or if each valve is periodi-cally inspected by leakage testing, ultrasonic examination, or radiographic inspection.
NRC has established a program to provide increased assurance that such multiple isolation barriers are in place in all operating Light Water Reactor plants designated DOR Generic Implementation Activity B-45.
In a generic letter of February 23, 1980, the NRC requested all licensees to identify the following valve configurations which may exist in any of their plant systems communicating with the PCS: 1) two check valves in series or 2) two check valves in series with a motor-operated valve'(MOV).
For plants in which valve configurations of concern were found to exist, licensees were further requested to indicate: 1) whether, to ensure integrity, continuous surveillance or periodic testing was currently being conducted, 2) whether any valves of concern were known to lack integrity, and 3) whether plant proce-dures should be revised or plant modifications be made to increase reliab ilit.y.
Franklin Research Center (FRC) was requested by the NRC to provide tech-nical assistance to NRC's B-45 activity by reviewing each licensee's submittal against criteria provided by the NRC and verifying the licensee's reported findings from plant system drawings.
This report documents FRC's technical review.
- 2. 0 CRI TE RIK 2.1 Identification Criteria For a piping system to have a valve configuration of concern, the follow-ing five items must be fulfilled:
- 1)
- The high-pressure* system must be connected to the Primary Coolant System;
- 2) there must be a high-pressure/low-pressure interface present in the line;
- 3) this same piping must eventually lead outside containment;
- 4) the line must have.one of the valve configurations shown in Figure l; and
- 5) the pipe line must have a diameter greater than 1-in.ch.
I 4
v1
~
~
v1
- ~
I 4
tA HP*
f
- LP Figure 1.
Valve Configura~ions Designated by NRC to be Included in Tilis Technical Evaluation
,~;..
t.; *.'
... ~ :.
3.0 :~ECHNICAL EVALUATION FRC has r~viewed *the res pons~ [Ref. 2) of. the Conunon*weal th E.dison Comp~ny PCS pressure*
(CWE) to NRC's generic ietter[Ref. I]. concerning the issue of
~
isolation va.lve configurations* for Quad.Cities Plant Unit 1.
The. licensee s tat~d i:hat ~one of their pi.ping systems hav~ any of the valve configurations 'of concern, ~s descr~b~d ;by the identification criteria.
FRC indep~ndently checked the 'pl~nt Piping and instrumentat'iori Diagrams J
(P&IDs) [Ref. 3) for pipi~g sysi~~s that ~ight have*these va~ve configura-tions.
In t~is review 6f the.Jicensee's res~ortse against the P&IDs and th~
ident:ific~tion criteria, FRC found no valve configurations o.f concern, thus verifying CWE's find:lngs *.
. 4 ~ 0 *. CONCLUSIONS In CWE's Quad Cities Plant Unit 1, all.piping systems larger than. 1-inch dia~eter that are inte~c~nriect~d'.to the PCS are free of the val~~ configura*
tions of concern *. The;ifore~ no. futhe*r modifi~ati~ns to this plant's Techni-cal Specifita~ion~ are necessary on this ac~ourit~
5.0 REFERENCES
Gen~ric *NRC *lett~r.. dated 2/23/80, fr6m Mr~* D. G. tisenhut, *Department of,Opereting'Re~ctorR (DOR), tb Mr. 'w.
)<'~ Nati'ghton,. Commonwealth Edison Coinpnny -C.CWE} *. *
[ 2J.. Co.mmoriweali:h. Edison Co~1>any i H ~espohE)~. to. the geueric NRC" i~t tet, d11ied
- 3/14/80; f~oiti Mi..w~ F. Naughton <cwt> to Mr. o~ G~ Eisenhut (DOR}.
[3]~
List of examined P&IQs:
- .*... *;~ -~*'.
Sargent & Lundy:
M-12. (Rev. F)
- M-15 M-35*
M-.36 M-37.
M-39
- (Rev *.
- H)*
(Rev. H)
(Rey. 'H).
(Rev. J)
(Rev. F)
M-40
( ~ev. H}
M-41 M-46 M-47.
'M-:-50 M;_459 M-:460 W-461*
(Rev. H}
.*(Rev~ 'H)
- (Rev. H) *
(Rev. H)
(Rev. E)
<R.ev. E> *..
(Rev.. A)
. ~-. *:.
. ~*-~..
TECHNICAL EVALUATION REPORT PRIMARY COOLANT SYSTEM PRESSURE ISOLATION VALVES COMMONWEALTH EDISON COMPANY QUAD CITIES UNIT 2 NAC DOCKET NO. 50-265 NRCTACNO.
12909 NACCONTAACT NO. NAC-03-79-118 Prepared by Franklin Research Center
. The Parkway at Twentieth Street Philadelphia, PA 19103 Prepared for Nuclear Regulatory Commission Washington, O.C. 20555 FRC PROJECT C5257 FRC TASK 242 Author:
P. N. Noell/T. c. Stilwell FRC Group Leader:
P. N. Noell
.Lead NRC Engineer: P. J. Polk July 21, 1980 This report was prepared as an account of work sponsored by an agency of.the United States Government. Neither the United States Government nor any agency thereof, or any of their employees, makes any warranty, expressed or implied, or assumes any legal liablllty or responsibility for any third party's use, or the results of such use, of -any information, apparatus, p*roduct or process disclosed In this report, or represents that its use by such third party would not infringe privately o~ned rights.
Qnklin Research Center.
A Division of The Franklin Institute
- The Benje min Franklin P11rkw11y. Phil11.. P11 I 910.3 (2 I 5) 448-I 000
1.0 INTRODUCTION
The NRC staff has determined that cer.tain isolation valve configurations iri systems connecting the high-pressure Primary Coolant System (PCS) to lower-pressure systems*extending out~ide containment are potentially significant.
contributors to an intersystem ioss..;.of-coolant accident (LOCA).
Such configu-rations have been found to represent a sigriificant factor in the risk computed for core melt accidents.
The s~querice of events leading to the core melt is initiated by the failure of two. in-series check valves to function as a pres-sure isolation barrier between the high-pressure Pc°S and a lower-pressure system extending beyond containment.
This causes an overpressurization and rupture of the low-pressure *system, which results in a LOCA that bypasses con-tainment.
The NRC has determined that th.e. probability of failure of these check valves as a pressure isolation barrier can be signifi~antly reduced, if the pressure at each valve is continuousli moniiored, or if each valve is periodi-cally inspected by leakage testing, ultrasonic examination, or radiographic inspection.
NRC has established a program to provide increased assurance that
- such mul~iple isolation barriers are in place in all operating Light Water Reactor plants designated DOR Gen~ric Implementation Ac:tivity B-45.
In a generic letter of February 23, 1980,. the NRC requested all licensees*
to identify the following valve configurations which may ~xist in any. of their plant systems connnunicating with the PCS: 1) two check valves in series or 2) two check valves in series with a motor-operated valve *(MOV)~ For plants in which valve configurations of concern were ~ound to exist, licensees were further requested to indicate: 1) whether, t.o ensure integrity, continuous surveillance or periodic testing was currently being conducted, 2) whether any valves of concern were known to lack integrity,* and 3) whether plant proce-dures should be revised. or plant modifications be made to increase reliability.
Franklin Research Center (FRC) w~s requested by the NRC to provide tech-nical aBsistance to NRC's B-45 activity by reviewing each licensee's submittal
~Jainst criteria provided by the NRC and verifying the licensee's reported
- findings from plant system drawings.
This report documents FRC's technical
.review.
-1.-
'..... ~
2.0 CRITERIA 2.1 Identification Criteria For a piping system to have a valve configuration of concern, the follow-ing five items must be fulfilled:
- 1)
The high-pressure :system must be connected to the Primary Coolant System;
- 2) there must be a high-pressure/low-pressure interface present in the line;
- 3) this same piping must eventually lead outside containment;
- 4) the line must have one of the valve configurations shown in Figure l; and
- 5) the pipe line must have*a diameter greater than 1-inch.
PCS'""
1/1
~
I
~
~
I I
l-/1 v1
~*
v1 I
HP 44t-----+----1*~ LP Figure 1.
Valve Configurations Designated by NRC to be Included in Thl.s T¢chnical Evaluation
.,.~
- .*i
3.0 TECHNICAL EVALUATION
FRC has reviewed the response [Ref. 2) of the Commonwealth Edison Company (CWE) to NRC's generic letter [Ref. l] concerning the issue of PCS pressure isolation valve configurations,for Quad Cities Plant Unit 2.
The licensee stated that none of their piping systems have any of the valve configurations of concer~, as described by the identification criteria.
FRC independently checked the plant Piping and: Instrumentation Diagrams (P&IDs) [Ref. 3) for piping systems that might have these valve configura-tions.
In this review of the iicensee's response against the P&IDs and the identification criteria, FRC found no valve configurations of concern, thus verifying CWE's findings.
4.0 CONCLUSION
S In CWE's Quad Cities Plant Unit 2, all piping systems larger than 1-inch diameter that are interconnected to the PCS are free of the valve configura..,.
tions of concern.
Therefore, no futher modifications to this plant's Techni-cal Specifications are necessary on this account.
- 5. 0 REFERENCES
[l).
Generic NRC letter, dated 2/23/80, from Mr. D. G. Eisenhut, Department of Operating Reactors (DOR), to Mr. W. F. Naughton, of Commonwealth Edison Company (CWE).
[ 2]
- Commonwealth Edison Company's response to the generic NRC letter, dated 3/14/80, from Mr. W. F. Naughton (CWE) to Mr. D. G. Eisenhut (DOR).
(3).
List of examined P&IDs:
Sargent & Lundy:
M-12 (Rev. F)
M-83 (Rev. E)
M-62 (Rev. G)
M-87 (Rev. F)
M-76 (Rev. F)
M-88 (Rev. F)
M-77 (Rev. F)
M-89 (Rev. E)
M-79 (Rev. D)
M-460 (Rev. E)
M-81 (Rev. D)
M-462 M-82 (Rev. D)
M-463