ML20069A475
| ML20069A475 | |
| Person / Time | |
|---|---|
| Site: | Quad Cities  |
| Issue date: | 09/30/1980 |
| From: | Debby Hackett EG&G, INC. |
| To: | NRC |
| Shared Package | |
| ML20069A478 | List: |
| References | |
| 1183-4172, NUDOCS 8010070327 | |
| Download: ML20069A475 (21) | |
Text
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1183-4172 SEPTEMBER 1980
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"ENERGYMEASUREMENTS GROUP
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3 TECHNICAL EVALUATION OF THE ELECTRICAL,
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INSTRUMENTATION, AND CONTROL DESIGN ASPECTS OF THE
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OVERRIDE OF CONTAINMENT PURGE VALVE ISOLATION AND OTHER ENGINEERED SAFETY FEATURE SIGNALS
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FOR THE QUAD CITIES NUCLEAR POWER STATION, UNITS 1 AND 2 E
(Dockets 50-254 and 50-265)
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1 DISCLAIMER This report was prepared as an account of work sponsored by the United
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States Government.
Neither the United States nor the United States Department of Energy, nor any of their empl oyees, makes any warranty, express or implied, or assumes any legal liability, or responsibility for the accuracy, completeness or usefulness of any information, apparatus, 1
product or process disclosed, or represents that its use would not infringe i
on privately owned rights.
Reference herein co any specific commercial product, process, or service by trade name, mark, manuf acturer, or other-1 wise, does not necessarily constitute or imply its endorsement, recommend-ation, or favoring by the United States Government or any agency thereof.
The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.
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September 1980 3
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TECHNICAL EVALUATION OF THE ELECTRICAL, INSTRUMENTATION, AND CONTROL DESIGN ASPECTS OF THE h
OVERRIDE OF CONTAINMENT PURGE VALVE ISOLATION AND OTHER INGINEERED SAFETY FEATURE SIGNALS FOR THE
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QUAD CITIES NUCLEAR POWER STATION, UNITS 1 AND 2 (Dockets 50 254 and 50 265)
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O. B. Hackett/B. Kountainis Approved for Publication b
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Department Manager This document is UNCLASSIFIED l
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' Nicnolas E. B(odericx Department Manager ll Work Performed for Lawrence Livermore NationalLaboratory under U.S. Department of Energy Contract No. DE-ACOS 76 NVQ 1183.
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ABSTRACT I
This report documents the technical evaluation of the electrical, instrumentation, and control design aspects of the override of containment purge valve isolation and other engineered safety feature signals for the Quad Cities Nuclear Power Station, Units 1 and 2.
The review criteria are based on IEEE Std-279-1971 requirements for the safety signals to all purge l
and ventilation isolation valves.
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N FOREWORD This report is supplied as part of
- t. e Selected El ec trical,
I n s trumen ta ti on, and Control Systems Issues (SEICSI) Program being i
l conducted for the U.S. Nuclear Regulatory Commi ssion, Of fice of Nuclear Reactor Regulation, Division of Operating Reactor;, by Lawrence Livermore National Laboratory, Field Test Systems Division of tne Electronics
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Engineering Department.
The U.S. Nuclear Regulatory Commission funded the work under an authorization entitled " Electrical, Instrumentation a':d Control System Support," B&R 20 19 04 031, FIN A-0231.
I The work was performed by EG&G, Inc., Energy Measurements Group, l
San Ramon Operations, for Lawrence Livermore National Laboratory under U.S.
Department of Energy contract number DE-AC08-76NV01183.
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TABLE OF CONTENTS Q
Page G
1.
INTRODUCTION.
1 2.
EVALUATION OF QUAD CITIES NUCLEAR POWER STATION, lh UNITS 1 AND 2 3
2.1 Review Criteria.
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2.2 Containment Ventilation Isolation Circuits
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dM Design Description.
4 2.3 Containment Ventilation Isolation System Design Evaluation.
6 2.4 Other Engineered Safety Feature System Circuits.
8 El 3.
CON auS10NS.
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REFERENCES.
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l TECHNICAL EVALUATION OF THE ELECTRICAL, l
INSTRUMENTATION, AND CONTROL DESIGN ASPECTS OF THE OVERRIDE OF CONTAINMENT PURGE VALVE ISOLATION AND OTHER ENGINEERED SAFETY FEATURE SIGNALS FOR THE QUAD CITIES NUCLEAR POWER STATION, UNITS 1 AND 2 (Dockets 50-254 and 50-265) 1
- 0. B. Hackett/B. Kountanis EG&G, Inc., Energy Measurements Group, San Ramon Operations l
1.
INTRODUCTION l
I Several instances have been reported where automatic closure of the containment ventilation / purge valves would not have occurred because the safety actuation signals were either manually overridden or blocked l
during normal pl ant operations.
These events resulted from procedural inadequacies, design deficiencies, and lack of proper management controls.
These events also brougnt inte question the mecnanical operability of the containment isolation valves themselves.
These events were determined by the U.S. Nuclear Regulatory Commission (NRC) to be an Abnormal Occurrence I
(#78-5) and were, accordingly, reported to the U.S. Congress.
As a follow-up on tnis Abnormal Occurrence, tne NRC staff is reviewing the electrical override aspects and the mechanical operability aspects of containnent purging for all operating power rectors.
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November 29, 1978, the NRC issued a letter entitled " Containment Purging During Normal Plant Operation" [Ref.13 to all boiling water reactor (BWR) and pressurized water reactor (PWR) licensees.
In a letter [Ref. 23 dated January 2, 1979, Commonweal th Edison, the licensee for the Quad Ci ties E PP
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Nuclear Power Station, Units 1 and 2, replied to tne HRC generic letter.
The evaluation of other engineered safety feature (ESF) systems Eas suo-mitted in response to IE bulletin 79-08 [Ref. 3].
Additional information (see References] was subsequently received and evaluated.
This document addresses only the electrical, instrumentatio'n, and-control (El&C) design aspects of.the containment ventilation isolation (CVI) and other ESFs.
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F. VALUATION OF QUAD CITIES NUCLEAR POWER STATION, UNITS 1 AND 2 l
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2.1 REVIEW CRITERIA The primary intent of this evaluation is to determine that the following NRC staff criteria are met for the safety signal, to all ESF l
equipment:
3 (1) Criterion no.1 - In keeping with the requirements l
of General Design Criteria 55 and 56, the over-
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- of one type of safety actuation signal (e.g., radiation) should not cause the blocking of pressure) for those valves that have no function besides containment isolation.
2 (2) Criterion no. 2 Sufficient physical features (e.g.,
keylock switches) are to be provided to facilitate adequate administrative controls.
(3) Criterion no. 3-A system-level annunciation of the overridden status should be provided for every I
safety system impacted and when any ovarride is active.
(See R.G. 1.47).
Incidental to this review, the following additional NRC design criteria were used in the evaluation:
(1) Criterion no. 4 - Diverse signals should be pro-vided to initiate isol ation of the containment g
ventilation system. Specifically, containment hign 4
radiation, safety injection actuation, and cortain-ment high pressure (where containment high pre sure is not a portion of safety injection actuation) should automatically initiate CVI.
5 "Ine following definition is given for clarity of use in this evaluation:
Override:
The signal is still present, and it is blocked in order to perform a function contrary to the signal. E wem e,-
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- l (2) Criterion no. 5 - The instrumentation and control systems provided to initiate tne E5F should De designed and qualified as safety-grade equipment.
(3) Criterion no. 6 - The overriding or resetting" of the ESF actuation signal should not cause any valve or damper to change position.
i Criterion 6 in this review applies primarily to other related ESF systems because implementation of this criterion for containment isolation have been reviewed.by the Lessons Learned Task Force, based on tne recom-mendations in NUREG-0578 Section 2.1.4 (Ref. 4].
Automatic val've reposi-tioning upon reset may be acceptable when containment i solation is not involved; consideration will be given on a case-by-case basis.
Accept-ability would be dependent upon system function, design intent and suitaole operating procedures.
CONTAINMENT VENTILATION ISOLATION CIRCUITS DESIGN DESCRIPTION 2.2 Quad Cities Nuclear Power Station, Units 5 and 2, has ESF trains for each unit which can cause isolation of the containment ventilation The containment ventilation system is labeled Primary Containment sy stem.
Isolation System (PCIS) on these units. One ESF train controls the inboard containment ventilation / purge isolation valves, and' the other train con-trols tne outboard isolation valves.
The initiating contacts for each train are described below:
(1) Automatic contacts (all one-out-of-two, taken twice logic)
(a) High dryweil p essure.
(b) Low reactor vater level.
- Tne following definition is given for clarity of use in tnis evaluation:
Reset: The signal has come and gone, and the circui t is being cleared to return it to the normal condition..
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(2) Manual Contacts None at system level. (Isolation may be accomplished by the individual PCIS-valve manual switches.)
NOTE: There is no radiation ini ti ated trip of the PCIS II valves.
High stack radiation will cause the reactor j
building ventilation ducts to trip snut to prevent the 4
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release from the stack.
The relays for each of the monitored plant conditions have con-Each train tacts in each of the two trains that control the PCIS valves.
is powered by a different electrical bus.
The PCIS circuits contain a reset switch, which functions as defined in this report.
The inboard torus and drywell vent valves are each bypassed with a 2-inch-diameter isolation v al ve.
These two 2-inch valves plus the 6-inch-diameter isolation valve to the standby gas treatment sys tem are utilized by the Atmospheric Control System ( ACS) to control the containment during postaccident operations.
These valves (e.g., 1601-61,-62 and -63 for Unit 1) have a designed electrical bypass capability.
Tne bypass h
circuit contains an interlock to prevent its operation if tne reactor is in the "run" modb.
The bypass switch is a keylock switch with the key con-trolled by the shift supervisor. The bypass condition is annunciated.
When a monitored plant condition calls for isolation, electric H
power is removed from the slave relays (e.g., 595-104A).
The slave relay contacts open to remove electric power from the solenoid valv'es, causing tne isolation valves to close.
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The PCIS-valve solenoid valves must remain energized in order for the isolation valve to be kept open.
The solenoid valve trio circuit contains a seal-in contact to maintain electric power to it as long 's a a
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'd PCIS signal is not present.
With a PCIS signal present, tne valves will not remain open and cannot be opened by their manual switch (with the exception of the three valves in the bypass circuit as described above).
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The PCIS signal cannot be cleared until the initiating condi-tion (s) is cleared.
When all initiating conditions are cleared, pressing the PCIS reset button will restore power to tne solenoid valve circuits.
I Pressing the FCIS reset button will also clear a bypass condition of tne The manual isolation valve postaccident operations system if one exists.
switches are pistol-grip handle, maintained-contact t"pe (GE type $6M SW).
Hence, once electric power is restored to the solenoid valve circuits, any isolation valve with its switch in the "open" positior will automatically reopen.
Incidental to this review, we have noted that the PCIS circuits To manually isolate do not contain a system-level manual isolation switch.
the PCIS valves. each of the individual manual switches must be turned to "close."
CONTAINMENT VENTILATION IS0LATION SYSTEM DESIGN EVALUATION 2.3 In response to this issue, on an interim basis, the 18-inch containment ventilation / purge isolation valves at Quad Cities Nuclear Power Station, Units 1 and 2 are mechanically stopped from opening more than 40 degrees.
l The PCIS actuation system has a reset switch but does not have an the ACS system has a postaccident Oypass override capability.
- However, Since the ACS capability for three valves as discussed in Section 2.2.
system is designed to control and/or mitigate the containment atmosphere following an accident, their evaluation has not been included since it is i
beyond the scope of criteria 1.
Therefore, we conclude that NRC staff that no deter-criterion no.1 is satisfied for the PCIS system, except mination has been made for the ACS system.
The ACS system bypass has a keylock swi tch whicn f acili tates acministrative control, as well as annunciation of the bypass condition We conclude control, and there is annunciation of the bypassed condition.
that NRC staff criteria nos. 2 and 3 are satisfied.
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The containment isolation automatic actuation signal is formed by the two conditions described in Section 2.2.
There is not an automatic PCIS actuation signal by high radiation.
We conclude tnat NRC staff cri-4
,terion no. 4 is not satisfied.
Judging from the information provided by the licensee, PCIS equipment at the Quad Cities Nuclear Power S ta ti on, Units 1 and 2, is designed and qualified as safety-grade equipment.
We conclude that NRC staff criterion no. 5 is satisfied.
When all initiating isolation conditions have been cleared, the PCIS actuation signal can be reset.
Upon resetting, any of the isolation valves with a manual swi tch in tne "open" position will automatically reopen.
In addition, any of the ACS valves with its manual switch in the "open" position will automatically reopen as soon as' the postaccident bypass circuit is switched to " bypass."
However, the licensee has com-pleted an interim modification so that the control switches for all of the valves must be in the closed position before the isolation signal can be reset [Ref. 53 The evaluation of this system has been done by the Lessons Learned Task Force as discussed in Section 2.1.
The PCIS circuits do not contain a system-level manual isolation switch 0, specified in the 1971 revision of IEEE Std-279.
The switch was not included in the design because the date of these units prececes the l
1971 revision.
However, the addition of a manual isolation switch would provide a quick and efficient means for the operator to isolate tne con-tainment in an emergency. The work involved would be to install the switch in the control panel and connect the associated wiring to the PCIS logic ci rcui ts.
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2.4 OTHER El4GINEERED SAFETY FEATURE SYSTEM CIRCUITS The licensee discussed its evaluation of otner ESF sys tems
( Atmospneric Control System, Core Spray, HPCI, and RHR) in response to IE bulletin 79-08 [Refs. 6 through 8]. Based on these subiaittals, we conclude that the NRC criteria are satisfied.
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CONCLUSIONS 3
The EI&C design aspects of containment purge valve isolation and other ESF signals for the Quad Cities Nuclear Power Station, Units 1 and 2, were evaluated using those design criteria stated in Section 2.1 of this report.
We conclude that the PCIS circuit design meets four of the six l
NRC staff criteria. One criterion not met is that under certain conditions the PCIS valves could automatically reopen.
However, the evaluation and acceptability of this design will be performed by the Lessons Learned Task Force in a separate review.
The other criterion not met is that the auto-matic containment isolation actuation signal does not include actuation by high radiation.
We recommend the installation of safety-grade radiation monitors to provide diverse isolation signals.
l We conci'd that the other ESF circuit designs discussed meet tne NRC staf f criteria.
The PCIS circuits do not contain a system-level manual isolation swi tch as specified in IEEE Std-279-1971.
We recommend that a manual I
system-level isolation switch be incorporated.
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REFERENCES 1
1.
NRC/ DOR letter (T.
Ippolito) to Comonweal th Edison, " Containment i
Purging During Normal Plant Operation," dated November 29, 1978.
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2.
Comonwealtn letter (C. Reed) to NRC (T. A. Ippolito), Dockets 50-254 and 50-265, (no title), dated January 2,1979.
j 3.
Comonwealth reply to IE Bulletin 79-08, (D.L. Peoples) to NRC (H.R.
Denton), (no titie), dated December 14, 1979.
4.
U.S. Nuclear Regulatory Comission, "TMI-2 Lessons Learned Task Force Status Report and Short-term Recomendations," NUREG-0578.
5.
Comonweal th letter (N.J. Kalivianakis) to NRC (E.G. Case), Dockets 50-254 and 50-265, (no title), dated January 2,1980.
6.
Comonweal th letter (R.F. Janecek) to NRC (T.A.
Ippolito), Dockets 50-254 and 50-265, (no title), dated February 28, 1980.
7.
Comonweal th letter (N.J. Kalivianakis) to NRC (E.G. Case), Dockets 50-254 and 50-265, (no title), dated April 14, 1980.
8.
Comonweal th letter (R.F. Janecek) to NRC (R.B. Bevan, Jr.), Dockets 50-254 and 50-265, (no title), dated July 29, 1980.
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P. O. Box 808 P. 0. Box 204 Livemore, California 94550 San Ramon, California 94583 M. H. Dittmore, L-97 (2 copies)
Author (2 copies)
C. E. Brown (4 copies) l B. G. Mayn
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LLNL/ Nevada NRC 2
Lawrence Livermore National Laboratory U. S. Nuclear Regulatory Commission P. O. Box 45 Washington, D.C.
20555 Mercury, Nevada 89023 i
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