ML20002A756
| ML20002A756 | |
| Person / Time | |
|---|---|
| Site: | Quad Cities  |
| Issue date: | 10/27/1980 |
| From: | Kountanis B EG&G, INC. |
| To: | |
| Shared Package | |
| ML20002A754 | List: |
| References | |
| NUDOCS 8011210474 | |
| Download: ML20002A756 (10) | |
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I-TECHNICAL EVALUATION OF THE ELECTRICAL, INSTRUMENTATION, AND CONTROL DESIGN ASPECTS OF THE ESF RESET CONTROLS FOR THE QUAD CITIES STATION, UNITS 1 AND 2 (Docket 50-254 and 50-265) by
- B. Kountanis
- EGAG, Inc., Energy Maaurements Group, San Ramon Operations 801223047f.
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- TABLE OF CONTENTS Page e
1 1.
BACKGROUND.
2.
INTRODUCTION.
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4, 3.
REVIEW CRITERIA 3
4.
. REVIEW GUIDELINES.
4 5.
EVALUATION 5
S.
SUMMARY
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- REFERENCES.
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1.
BACKGROUND f
9 A potential problem regarding the resetting of engineered safety feature actuation signals (ESFAS) has been discovered at several operating i
nuclear power plants. Specifically, it was found that upon reset of an ESF signal certain safety-related equipment moves out of the emergency mode and returns to the non-safety mode.
During a review of system operation at North Anna Nuclear Power Plant, Unit 1, which occurred following a unit trip and subsequent safety injection on November 6,1979, it es discovered that certain equipment important to safety, such as the control room habitability system dampers, returned to non-safety mode after the ESF signal was reset.
Further in-vestigation by both Virginia Electric and Power Company (VEPCO), the licensee for North Anna, and Stone and Webster Engineering Corporation, the plant's architect-engineer, revealed that other safety-related equipment also returned to non-safety mode after the ESF signal was reset.
This return to non-safety mode caused the safety-related equipment to operate less conservatively than assumed in the safety analysis.
This deficiency may be common to Stone and Webster implementa-tions of Westinghouse designs, as the same potential problem was found at both Peaver Valley and Surry nuclear plants and it is also related to probl> ss at Millstone, Unit 3, and Jamesport, Units 1 and 2, that were repork:d in Issue 4 of NUREG-0138.
All four of these plants are Stone and Webster / Westinghouse plants.
The NRC reviewed selected areas of ESFAS reset action on PWR facilities.
In some cases, this review was limited to an examination of logic diagrams and procedures.
It has been determined that logic diagrams may not adequately reflect as-built conditions; therefore, the review of drawings must be done at the schematic / elementary diagram level.
There have been several comunications to licensees from the NRC on ESF reset actions.
Some of these communications have been in the form of generic letters on containment venting and purging during normal opera-tions which were issued in November 1973 and October 1979; others were in Inspection and Enforcement Bulletins 79-05, -05A, -05B, -06A, -05B, and -08 which addressed the events at TMI-2 and in NUREG-0578, TMI-2 Lessons Learned Task Force Status Report and Short-Term Recommendations.
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1 2.
INTRODUCTION On March 13, 1980, the USNRC Office of Inspection and Enforcement i
(!&E), issued I&E Bulletin 80-06, entitled " Engineered Safety Feature (ESF) i Reset Controls " to all PWR and BWR facilities with operating licenses.
ISE Bulletin 80-06 requested that the following actions be taken by the
-licensees:
(1)
Review the drawings for all systems serving safety-related functior.s at the schematic / elementary diagram I
level to determine whether or rot upon the reset of an l
ESFAS, all associated safety-related equipment remains in its emergency mode.
(2)
Verify that the actual installed instrumentation and controls at the facili ty are consistent with the schematics reviewed in Item 1 above by conducting a test to demonstrate that all equipment remains in its emergency mode upon removal of tne actuating signal and/or manual resetting of the various isolating or' actuation signals.
Provide a schedule for the per-formance of the testing in your response to this bulletin.
(3)
If any safety-related equipment does not remain in its emergency mode upon reset of an ESF signal at your facility, describe proposed system modification, design change, or-other corrective action. planned to resolve the problem.
(4)
Report in writing within 90 days the results of your review, include a list of all devices which respond as discussed in Item 3 above, actions taken or planned to assure adequate equipment control, and a schedule for implementation of corrective action.
This document addresses only the electrical, instrumentation and control (EI&C) design aspects of the ESF reset controls.
This documert covers the licensee s response to I&E Bulletin 80-06 and the licensee's proposed system modification, design change, and other corrective action planned to resolve the problem.
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3.
REVIEW CRITERIA The following criteria were used to evaluate the licensee's response (s):
(1)
ISE Bulletin 80-06, " Engineered Safety Feature (ESF)
Reset Controls."
(2)
The NRC staff position requires that unless an. alter-native is justified by the licensee and accepted by the NRC staff, upon the reset of ESF signals (such as a safety. injection actuation signal), all affected equipment shall remain in its emergency mode.
If there is multiple reset sequencing, none of the reset actions shall cause the affected equipment to deviate from its emergency mode.
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REVIEW GUIDELINES The following guidelines were used in this review:
(1)
Review and tabulate the licensee's response to I&E Bulletin 80-06 and other related documentation.
l (2)
Deternine if the licensee's response or other related t
documentation addresses all of the items requested in I&E Bulletin 80-06.
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(3)
If additional documentation requested is not received I
within four months (from the date of the letter to the NRC technical contact), discontinue the review and f
submit a report stating that there is insufficient infonna tion.
(4)
Review all submitted documentation to determine if the ESF Reset Controls satisfy the requirements of the review criteria.
If it is found that the submitted documentation is inadequate, clari fy those problem areas in a telephone conference call (or meeting).with the licensee.
If the additional documentation re-quested ddring the conference call (or meeting) is not received within two weeks (from date of contact),
discontinue the review and submi t a report which treats the questionable area t.s a non-compliance item.
(5)
Conduct a review of any licensee-proposed system modification, design change or other corrective action planned to resolve any problem areas to determine if the proposal satisfies the review criteria.
(6)
If the licensee does NOT propose any corrective action for the non-compliance areas, cite their justifica-tions or bases as a part of the report.
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EVALUATION l
The licensee for Quad Cities Station, Units 1 and 2, Commonwealth l
Edison, has stated in their response to I&E Bulletin 80-06 that no equip-ment diverts from its emergency mode when the actuation signals are reset.
i However, there are manual resets at the system level for valves and equip-ment which may return the equipment to its normal operating status.
The ESF systems that were considered by the licensee in this review are as follows:
(1)
Reactor protection system initiation (2)
Primary containment isolation (3)
ECCS and diesel generator initiation (4)
Reactor building vent isolation (5)
Off-gas system isolation (6)
Control room vent isolation.
The following systems have manual resets at the system level to reset valves and equipment:
(1) Off-gas trip reset - Re-opens off-gas isolation valves after high radiation trip signal has cleared.
Resets 15-minute timer on off-gas spike.
(2) RPS scram reset - Closes scram valves and re-energizes scram pilot solenoid valves after RPS trip signals have cleared.
(3) Control room vent isolation reset - Re-opens outside air and exhaust air dampers, provided that SBGT in-itiation, main steam high flow, smoke detector, and cold outside air signals have cleared.
(4) Reactor building vent isolation reset Opens vent isolation dampers after isolation signals have clear-ed.
(5) Groups I, II, and III PCI resets - Permissive to re-open isolation valves, provided that the valves in the group are first placed in the closed position and all isolation signals are cleared for that group.
(6) Auto-blowdown timer reset - If auto-blowdown initia-tion :ignals have cleared, can re-close ielief valves.
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.(7) Auto-blowdown drywell pressure reset - Resets drywell pressure relays for auto-blowdown after drywell high pressure condition has cleared.
Allows relief valves to re-close if low-low reactor water level condition has reset.
(8) HPCI and RCIC isolation resets - Permissive to re-open Group IV or Group V isolation valves, provided tnat isolation signals have cleared.
-(9) HPCI drain valves reset - Re-opens HPCI drains to condenser and closes drains to drain pot, provided that initiation signals have cleared.
(10) RHR logic resets - Permissive to re-open RHR valves W-after LPCI initiation signals have cleared.
Al so,
permissive to reprsition LPCI and recirculation valves after LPCI loop-select initiation signals have clear-ed.
(11) Group II, M0-1001-29 valve reset Permissive for MO-1001-29A/B to auto-open after Group II isolation while shutdown cooling is in progress.
The above information indicates that when the systems described are manually reset, some type of action may result wi thout a second deliberate act taking place.
Furthermore, the licensee has not provided a proposed system modification, design change, or other corrective action to resolve the problem.
Therefore, the licensee has not compliad with the requirements of Action Item 3 of I&E Bulletin 80-06.
Because a description of actions taken or planned to assure adequate equipment control and a schedule for their implementation have not been included with the submittal, we have determined that the licensee is partially non-compliant with Action Item 4 of I&E Bulletin 80-06.
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SUMMARY
The licensee, Commonwealth Edison, has reviewed the drawings to determine if any safety-related equipment deviates from emergency mode upon reset of an ESF actuation signal, and has verified that the equipment operates as shown on the schematics.
The licensee is, therefore, in com-pliance with Action Items 1 and 2 of I&E Bulletin 80-06.
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The licensee has identified 11 systems which have equipment that i
may deviate from emergency mode upon manual reset at the system level for i
valves and equipment.
They have not provided a description of actions i
taken or planned to assure adequate equipment control, nor a schedule for their implementation.
It is, therefore, concluded that the licensee has not complied with the requirements of Action Item 3 and portions of Action Item 4 of I&E Bulletin 80-06.
A subsequent letter or supplemental technical evaluation will be generated following the I&E-regional inspector / licensee response to this
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REFERENCES i
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Comonwealth Edison letter (D.L.
Peoples) to NRC (J.G. Keppler),
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" Response to I&E Bulletin 80-06," dated June 10, 1980.
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