ML20059C925
| ML20059C925 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 08/21/1993 |
| From: | Rueger G PACIFIC GAS & ELECTRIC CO. |
| To: | |
| References | |
| OLA-2-I-MFP-111, NUDOCS 9401060212 | |
| Download: ML20059C925 (7) | |
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March 5, 1992 93
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o ci i PG&E Letter No. DCL-92-055 U.S. Nuclear Regulatory Commission ATTN:
Document Control Desk Washington, D.C.
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Re:
Docket No. 50-323, OL-DPR-82 Diablo Canyon Unit 2 Licensee Event Report 2-91-012-00 Failure to Meet Technical Specification 4.5.2 When Visual Inspections Were Not Performed Due to a Programmatic Deficiency Gentlemen:
Pursuant to 10 CFR 50.73(a)(2)(i)(B), PG&E is submitting the enclosed Licensee Event Report (LER) concerning failure to meet Techni :1 Specification 4.5.2.
Visual inspections were not performed oue to a programmatic deficiency caused by a lack of a comprehensive program for control of material after containment integrity was established.
This event has in no way affected the health and safety of the public.
Sincerely,
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Gregory M. Rueger cc:
Ann P. Hodgdon John B. Martin Philip J. Morrill Harry Rood Nu:L ncumcay ccmseN ard J. Wong
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i LICENSEE EVENT REPORT (LER) 185986 1 BLO CANYON UNIT 2 l
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a On October 12, 1991, at 2340 PST with Unit 2 in Mode 4 (Hot Shutdown) at D percent following the Unit 2 fourth refueling outage (2R4), containment integrity was po.er, established.
fror October 16, 1991 to February 4, 1992, numerous investigations were conducted to identTfy the cause of debris left in containment.
These investigations consisted of a QC surveillance, an Engineering evaluation, personnel interviews, a review of containrent entry records, and several meetings of the Technical Review Group (TRG).
During these investigations, four individuals stated that they had not completed an STP M-456, " Containment inspection When Containment Integrity is Established," data sheet.
Based on the results of these investigations, on February 4, 1992, the TRG conservatively determined that Technical Specification 4.5.2.c had not been met.
The root cause of this event was determined to be lack of a comprehensive program for control of materials af ter establishment of containment integrity.
To prevent recurrence, a procedure will be developed to establish a comprehensive program for control of material after containment integrity has been established.
Appropriate personnel will be trained on this procedure.
ICllS/E5K
LICENSEE EVENT REPORT (LER) TEXT CONTINUATION 185966
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Plant Conditions Unit 2 was in Mode 4 (Hot Shutdown) at 0 percent power following the Unit 2 fourth refueling outage (2R4).
11.
Description of Event A.
Summary:
After numerous investigations, on February 4, 1992, a Technical Review Group (TRG) determined that the visual inspection required by Technical Specification (TS) 4.5.2.c was not performed during Modes 1 through 4.
TS 4.5.2.c specifies that a visual inspection be performed following each containment entry to verify that no loose debris (rags, trash, clothing, etc.) is present that could be transported to the containment sump and cause restriction of the RHR (BP)(P) pump suction flow during LOCA conditions.
This visual inspection was not always performed during Mode 4.
During these investigations, four individuals who made containment entries stated that they had not completed an STP M-45B data sheet in compliance with the surveillance requirements necessary to meet TS 4.5.2.c.
B.
Background:
Technical Specificetion (TS) 4.5.2.c requires that each emergency core cooling system (ECCS) subsystem (BE)(BP)(BQ) be demonstrated operable by a visual inspection of containment (1) prior to establishing containment integrity for all cccessible areas, and (2) at the completion of each containment entry after containment integrity is established for all affected areas. These inspections are intended to verify that no loose debris is present that could be transported to the containment sump during a loss-of-coolant accident (LOCA) condition.
Such debris could potentially restrict tne RHR pump suction flow.
Surveillance Test Procedure (STP) H-45A, " Containment Inspection Prior to Establishing Containment Integrity," verifies that no loose debris exists in containment and satisfies the requirements of TS 4.5.2.c.(1).
STP M-45B, " Containment inspection When Containment Integrity is Established," requires that an inspection verification data sheet be completed to verify that no loose debris remains in containment after containment integrity has been established.
This inspection satisfies the requirements of TS 4.5.2.c.(2).
10llS/85K
LICENSEE EVENT REPORT (LER) TEXT CONTINUATION 18598G<
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Event
Description:
On October 12, 1991, at 2340 PST, with Unit 2 in Mode 4 (Hot Shutdown), STP M-45A was performed and containment integrity was established.
After entry into Mode 4, Radiation Protection expressed concerns to Outage Mar:agement and Quali" Control (QC) about material left unattended in containment.
This material consisted of tools, plastic tool bags, clothing, and other similar items.
Each time this material was identified, it was removed from containment.
These concerns led QC to perform a surveillance of the containment integrity.
From October 16 to October 21, 1991, QC performed a surveillance of the containment inspection activities associated with STP M-458.
OC personnel found numerous instances of material left unattended or abandoned in containment.
On December 16, 1991, PG&E Design Engineering completed an evaluation on the potential ef fects of the material (small plastic bag, wipealls, tool bag, water jug, and tool bin) found in containment between October 16 and October 21, 1991.
This evaluation determined that only the material left in the sump level of containment could have been transported to the containment sump screen, but had no potential to get into the sump and restrict its flow during a LOCA.
On December 17, 1991, the TRG reconvened to review the QC surveillance results and discussed the work control process in containment and the operability of the containment recirculation sump during a design basis accident.
Additional investigations by the TRG were conducted.
From October 16, 1991 to February 4, 1992. numerous investigations were conducted.
These investigations consisted of a QC surveillance, an Engineering evaluation, personnel interviews, a review of containment entry records, and several meetings of the Te:hnical Review Group (TRG).
The investigations found that four individuals indicated that they had not completed an STP H-45B data sheet.
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on the results of these investigations, on February 4, 1992, the TRG conservatively determined that TS 4.5.2.c had not been met.
D.
Inoperable Structures, Components, or Systems that Contributed to the Event:
None.
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E.
Dates and Approximate Times for Major Occurrences:
1.
October 12, 1991, at 2340 PST:
Event date.
STP M-45B was not performed after containment integrity had been established i
in preparation to enter Mode 4.
2.
February 4, 1992:
Discovery date.
TRG determined that the numerous occurrences of material left unattended in containment constituted a violation of TS 4.5.2.c.
F.
Other Systems or Secondary Functions Affected:
None.
G.
Method of Discovery:
QC personnel identified this problem as a result of investigations performed after Radiation Protection personnel expressed concerns about tools, materials, and loose debris left abandoned in containment, Personnel interviewed as part of the investigations stated that they did not always complete an STP M-45B data sheet af ter containment integrity was established.
H.
Operators Actions:
None.
I.
Safety System Responses:
None.
111.
Cause of the Event STP M-45B specifies that the Shift foreman is responsible for identifying / assigning an individual for conducting STP M-45B surveillance during Modes 1 through 4.
STP M-45B provides an inspection verification data sheet which is required to be completed to verify that no material is left after work has been completed. This procedure was inadequate to control the high level of activity in containment during a heat-up and mode change from a refueling outage.
Investigations determined that there was not a consistent method for initiating the performance of STP M-45B during an outage after containment integrity is established or for controlling material at a work site while work is in progress, 10llS/85K
LICENSEE EVENT REPORT (LER) TEXT CONTINUATION 185966 IA !LIIT hAN[ (3)
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Immediate Cause:
Haterial was found abandoned or unattended after containment integrity was established, contrary to the requirements of STP M-458.
B.
Root Cause:
The root cause of this event has been determined to be lack of a comprehensive program for control of material af ter containment integrity is established.
C.
Contributory Cause:
Lack of awareness by some individuals of STP M-45B procedural requirements and its applicability contributed to the cause of this event.
IV. Analysis of the Event PG&E Design Engineering conducted an evaluation of the potential effects of the material left in containment between October 16 and October 21, 1991.
The evaluation concluded that only the material left on the Unit 2 containment recirculation sump level (small plastic bag, wipealls, tool bag, water jug, and tool bin) were postulated to migrate to the sump under LOCA cnnditions.
PG&E Design Engineering determined that even if the material left in containment migrated to the sump, there was enough available free area to support the RHR system flow requirements during a LOCA.
Because the RHR pumps could draw adequate reactor coolant from the containment recirculation sump with the material postulated to be partially blocking the sump screen, the ECCS would be operable.
It was determined that the material left in containment would not have passeo through the 3/16-inch mesh screen installed over the sump grating assemblies.
In conclusion, PG&E Design Engineering determined that the material left in containment would not have prevented the containment recirculation sump from fulfilling its safety-related function during a design basis accident.
Therefore, the health and safety of the public were not affected by this event.
t V.
Corrective Actions A.
Immediate Corrective Action-Containment was inspected and all material was removed.
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B.
Corrective Action to Prevent Recurrence:
A new procedure is being developed to establish a comprehensive
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program for control of material after containment integrity has been established. Appropriate personnel will be trained on this procedure.
VI. Additional Inf.gemation A.
Failed Components:
None.
B.
Previous LERs on Similar Problems:
None.
1 1
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