ML20217C413
| ML20217C413 | |
| Person / Time | |
|---|---|
| Issue date: | 09/26/1997 |
| From: | Rossi C NRC OFFICE FOR ANALYSIS & EVALUATION OF OPERATIONAL DATA (AEOD) |
| To: | Gillespie F, Holahan G, Laines G NRC (Affiliation Not Assigned) |
| Shared Package | |
| ML20217C417 | List: |
| References | |
| NUDOCS 9710010385 | |
| Download: ML20217C413 (4) | |
Text
_
hgP "849 e
9i t
UNITED STATES j
,j NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20666-0001
's, p'
September 26, 1997 MEMORANDUM TO:
Frank P. Gillespie, Director, DISP:NRR Gary M. Holahan, Director, DSSA:NRR Gus C. Laines, Acting Director, DE:NRR Jack W. Roe, Acting Director, DRPM:NRR R. Lee Spessard, Director, DRCH:NRR Lawrence C. Shao, Director, DET:RES M. Wayne Hodges, Director, DST:RES Joseph A. Murphy, Acting Director, DRA:RES James T. Wiggins, Director, DRS:RGN l
'ohns P. Jaudon, Director, DRS:RGN il John A. Grobe, Acting Director, DRS:RGN ill Arthur T. Howell, Director,.DRS:RGN IV FROM:
Charles E. Rossi, Safety Programs Division Office for Analysis and Evaluation of Operational Data
SUBJECT:
REVIEW OF UNDETECTED FAILURES OF SAFETY SYSTEMS Attached for your information and use is an engineering evaluation,
- Review of Undetected Failures of Safety Systems." The purpose of the evaluation was to analyze a sample of data on such failures. A set of 33 events involving such failures were identifiad by a search of the Accident Sequence Precursor (ASP) database for the time period 1991 through 1993. The failures were analyzed and evaluated with respect to their discovery methods, failure rate, failure cabses, corrective and preventive actions by the licensees, and regulatory actions.
The failures existed in systems important to safety and,in some cases, remained undiscovered for a long time,4 failures for a period of 1 to 10 years and another 4 for more than 10 years and up to 18 years. Although information is not definitive, an additional four events may have gone undiscovered since initial startup while two others existed since a plant modification.
More than 75 percent of the failures were discovered via testing or analysis and ovaluation of operational problems. The causes of failures in about 70 percent of the events were component failure, design deficiency, or inadequate testing or maintenance procedures. The C.$10' f(b6kh 0"w )
CONTACTS: Sada V. Pullani, AEOD/SPDIRAB, (301) 415-6843 Earl J. Brown, AEODISPD/RAB, (301) 415 7572
( \\
fh$ Nlll
,,1eo,o s e,2e rxn b
PDR ORQ NEXD
i f
(
Multiple Addressees more frequent corrective or preventive actions taken by the licensees were design change (plant modification), additional training or guidance for plant personnel, new or changes in operating procedures, and changes in maintenance procedures. Although the licensees' actions appeared appropriate for the specific events, it is not clear the effods would generically apply to other plants.
Although testing was identifi' a most frequently as the discovery method of the undetected ta. ore, our review indicated the failure was often peripherally related to the test. For example, in approximately 60 percent of the events, the failure detected or related deficiency revealed was not within the anticipated or defined purpose of the prescribed test. This appears to illustrate a need for improved definition of post work actions (tests, procedures, etc.) to confirm or assure component or system operability, in a similar context, the short duration (less than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />) events involved programmatic deficiencies and were discovered through fortuitous circumstances.
The Event Assessments and Generic Communications Branch and Inspection Program Branch of NRR, and Reliability and Risk Assessment Branch of AEOD provided review comments on a draft of this report. Their comments were resolved and their suggestions for improvement were incorporated to the extent feasible and consistent with the scope of the report.
Attachment:
As stated cc w/att.:
V. K Chexal, EPRI Pat Lewis, INPO Debble W. Queener, NOAC Distributicn w/att.:
PUBLIC AChaffee, NRR i Pas C enter >
RWessman, NRR RAB R/F MMayfield, RES SPD R/F REmrit, RES TTMartin RSavio, ACRS FCongol TOMartin, OEDO KRaglin AThadani, DEDE DHickman JMitchell, OEDO PBaranowsky RZimmerman, NRR BSheron, NRR C:\\NGN\\WPWIN\\WPDOCS\\MEMOUNFL.SVP
- See previous concurrence:
.e,y or ein eacwn.nt.inee.n e box: c copy weout en.ctc nv.ncan v copy.m.nacten.nvasow.
OFFICE RAB
[E RAB lE RAB lE RAB lE C:RAB lE D:SPD lR NAME SPultani:mmk EBrown Rueyd GLanik JRosenthal CRospr~s a DATE 09/11/97' 09/11/97' 09/-/97 09/12/97*
09/12/97' T A(97 ~ '
OFFICIAL RECORD COPY
I i
i Multip 9 Addressees more frequent corrective or preventive action? taken by the licensees were desi changes (plant modification), additional training or guidance for plant personnel, new or ange in operating procedure, and change in maintenance procedure. Although the li nsees' actions appeared appropriate for the specific events, it is not clear the efforts woul enerically apply to other plants.
Although testing was identified most frequently as the discovery mt th of the undetected failure, our review indicated the failure was often peripherally related o the test. For example, in approximately 60 percent of the events, the failure detected or r ated deficiency revealed was not within the anticipated or defined purpose of the prescrib test. This appears to illustrate a need for improved definition of post work actions (te s, procedures, etc.) to confirm or assure component or system operability, in a similar cont st, the snort duration (less than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />) events involved programmatic deficiencies and w e discovered through fortuitous circumstances.
The Event Assessments and Generic Communication Branch and Inspection Program Branch of NRR, and Reliability and Risk Assessment Bran of AEOD provided review comments on a draft of this report. Their comments were resolve and their suggestions for improvement were incorporated to the extent feasible and consiste with the scope of the report.
Aitachment: As stated cc w/att.:
V. K. Chexal, EPRI Pat Lewis, INPO Debble W. Queener, NOAC Distribution w/att.:
PUBLIC AChaffee, NRR File Center RWessman, NRR RAB R/F MMayfield, RES SPD R/F REmrit, RES TTMartin RSavio, ACRS FCongel TOMartin, OEDO KRaglin AThadani, DEDE DHickman JMitchell, OEDO PBaranow y RZimmerman, NRR BSheron, NRR H:\\
\\PULLANI\\MEMOUNFL.SVP
- Se previous concurrence:
(o e em a men nt. inou. in m. w c cm.=nn nv.neg
. e mem FOFFICE RAB l
RAB l
RAB l
RA T//[l /)'C:RAB %
D:SPD l
NAME SPullani:mmk EBrown RLloyd Gjd@ '
JRosenthal CAossi DATE o9/11/97' 09/11/97' 09/ /97 69//M7 09f/97
/ /97 OFFICIAL RECORD copy
t i
l Multiple Addressees more frequent corrective or preventive actions taken by the licensees were design change (plant modification), additional training or guidance for plant personnel, new or change in operating procedure, and change in maintenance procedure. Although the licensees' a ns appeared appropriate for the specific events, it is not clear the efforts would genericall apply to other plants.
Although testing was identified most frequently as the discovery method of the detected failure, our review indicated the failure was often peripherally related to the t t, For example, in approximately 60 percent of the events, the failure detected or related d sciency revealed was not within the anticipated or defined purpose of the prescribed test. his appears to illustrate a need for improved definition of post work ac'!ona tests, pr ures, etc.) to confirm s
or assure component or system operability. In a sitah, context, th hort duration (less than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />) events involved programmatic deficiericles and were di vered through fortuitous circumstances.
The Event Assessments and Generic Communications Br ch and Inspection Program Branch of NRR, and Reliability and Risk Assessment Branch of OD provided review comments on a draft of this report. Their comments were resolved an elr suggestions for improvement were incorporated to the extent feasible and consistent wi the scope of the report.
Attachment:
As stated cc w/stt :
V. K. Chexal, EPRI Pat Lewis, INPO Debbie W. Queener, NOAC Distribution w/att.:
PUBLIC Chaffee, NRR File Center RWessman, NRR RAB R/F MMayfield, RES SPD R/F REmrit, RES TTMartin RSavio, ACRS FCongel TOMartin, OEDO KRaglin AThadani, DEDE DHickman JMitchell, OEDO PBaranow y RZimmerman, NRR BSheron, NRR C:\\N
\\WPWIN\\WPDOCS\\MEMOUNFL,SVP
,To e copy at #de document. Indk.aw in the box: 'C' = copy weeut attachmentenemure T = Copy with attachmenV6 OFFICE RAB lC RAB 6
RAB l
RAB C:RAB D:SPD
[
NAME SPultani:mmlL_ _ EBrownES RLloyd GLanik JRosenthal CRossi DATE 09/n/97,kCI. 09m/97 ~
09/ /97 o9/ /97 09/ /97
/ /97 f
OFFICIAL RECORD COPY
_ _ _.