ML20128P560
| ML20128P560 | |
| Person / Time | |
|---|---|
| Issue date: | 02/22/1993 |
| From: | Novak T NRC OFFICE FOR ANALYSIS & EVALUATION OF OPERATIONAL DATA (AEOD) |
| To: | Grimes B Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20128P564 | List: |
| References | |
| NUDOCS 9302250007 | |
| Download: ML20128P560 (3) | |
Text
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<[ f%,, UNITED STATES F 4[ _g. NUCLEAR REGULATORY COMMISSION r, ;-. WASHINGTON, D, C,20555 :
[ FEB 2 21993 MEMORANDUM FOR: -Brian K. Grimes, Director-Division of Operating Reactor Support Office of Nuclear Reactor Regulation FROM: Thomas M. Novak, Director Division of Safety Programs Office for Analysis and Evaluation of Operational Data
SUBJECT:
HUMAN FACTORS ASPECTS OF BOILING WATER REACTOR REACTIVITYc MANAGEMENT EVENTS DURING POWER OPERATIONS Enclosed for your consideration is a report on the human factors aspects of 17 boiling water reactor (BWR) reactivity management events that occurred during-power operations. The report may contain useful insights related toLcertain NRR activities.such as operator licensing and human factors reviews. : This report documents the review of operational events from mid-1988 to present-that involved reactivity events leading to BWR reactor' trips from Modes 1 and 2.
Events were ' identified by searching databases, including licensee event reports (LERs) coded in the Sequence Coding and Search ~ System, and LERs-contained in the Nuclear Documents System. Events with equipment malfunctions', such as a turbine control valve or main steam isolation valve closure, that led to a reactor trip without time for operator response prior to .the trip were' not included in this report. Manual scrams were not included.
In the report, n.any corrective actions taken by. licensees were identified. .
.These corrective actions were. presented as " lessons learn _ed" that may be useful for other licensees to consider _in order to improve performance in this crea.
The-following findings and associated conclusions were developed:
- From 1988 to.1989 there.was a perceptible drop in the number of BWR reactivity. events. From 1989 to_present there was no-discernible trend. No plant was. identified as an outlier.
. The events were of icw safety _ significance. The reactor automatic-
-protective equipment functioned to shut-down the reactor in'all Cases. -
- Over half of the reactivity events occurred during startup, and about 30 percent occurred during plant shutdowns. Only _18 percent
[ ( L occurred during. steady state operation at high power. 3 O< "
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- Every event had human factors aspects, while less than ha # of the event s involved equipment failure.
The human performance weaknesses were in: (1) procedures, (2) operator knowledge, (3) command, control and communications, (4) human-machine interface, and- (5) impromptu operator actions.
The equipment failures involved feedwater or condensate system valves (3),
pressure regulators (2), turbine stop valve and bypass valve position indication, and a safety relief va Ive.
The physical causes of reactivity insertion events were: (1) pressure transients, (2) cold feedwater injection, (3) plant cooldown, (4) recirculation flow increase, and (S) control rod withdrawal .
If you have any questions, please do not hesitate to contact me at 492-4484 or John Kauffman of my staff at 492-4436. We shall be happy to meet with you or your staff to discuss thi s matter.
Orichl Signod by.
Thomas M. Novak, Director Division of Safety Programs Office for Analysis and Evaluation of Operational Data
Enclosure:
As stated Distribution:
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The human performance weaknesses were'in: (1) procedures,2(2);? ope /[ tor 4
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knowledge, (3)- command, control- and communications, (4) human-machine '
interface, and (5)-impromptu operator actions.
The equipment failures involved feedwater or condensate'sys m valves (3),
pressure regulators (2), turbine stop valve and bypass : val e position '
indication, and a safety relief valve. -l The physical causes of reactivity insertion events w re:, (1) pressure .
- transients, (2) cold feedwater injection, (3) plant ~ ooldown, (4)-
- recirculation flow increase, and (5) control rod thdrawal.- -
a If you have any questions, please do not hesitj e to contact me at 492-4484 or John Kauffman of my staff at 492-4436. -We s dll be-happy to_ meet with you or'-
your staff to discuss this matter. ,
homas'M. Novak, Director ,
Division of Safety programs Officeifor Analysis and Evaluation-of Operational Data
Enclosure:
As stated Distribution:
PDR / KBrockman Central: File '
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-JRosenthal . MTaylor,- EDO--
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