ML20062J980
| ML20062J980 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 08/18/1993 |
| From: | AFFILIATION NOT ASSIGNED |
| To: | |
| References | |
| OLA-2-I-MFP-051, OLA-2-I-MFP-51, NUDOCS 9311190395 | |
| Download: ML20062J980 (9) | |
Text
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NCR DCO-93-h$-3 tine 7, MO Rev. 00 1993 NCR DCO-93-EM-NO30 COVERS NOT INSTALLED INSIDE HOT SHUTDOWN PANEL g,.,
MANAGEMENT
SUMMARY
- Q%"
Covers not installed the hot shutdown panel for both Unit 1 and Unit 2.
There are two 16 inch by 18 inch covers that should complete the enclosure that surrounds the switches linside the hot shutdown panel.
The covers were observed to be laying in the bottom of the back of the hot shutdown panel.
The mounting screws that should have been installed were no where to be found.
New screws were procured and the covers were re-installed inside the hot shutdown panel.
This write-up, dated June 7, 1993, includes minutes from the TRG s
meeting held on June 1, 1993.
The TRG concurred that this event should be addressed under NCR DC1-93-EM-N019, " Unit 1 4kV RHF Hinged Panel".
Both NCR's address the failure to return the panel to its original configuration following work related activities within the panel.
It was agreed that a single NCR would best address a programmatic solution to the problem.
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.NCR DCO-93-EM-NO30 Rev. 00 1
June'7, 1993 NCR DCO-93.-EM-N030 COVERS NOT INSTALLED INSIDE HOT SHUTDOWN;. PANEL I.
Plant Conditiong i
Units 1 and 2 have been in various Modes'and-at various i
power levels with the conditions described below.
l II.
Descriotion of-Event
-A.
Summary:
~
~ ~
Covers not installed the hot. shutdown panel:for both Unit 1 and Unit 2-.
There are two 16sinch'by 18 inch
~
covers that should complete 1the enclosure.that-r surrounds-the switches inside the hot shutdown panel.
The covers were observed to lx3 laying n1the bottom of~
.the back.of the hot shutdown' panel.
The. mounting.
screws that should have been installed were no where to i
be found.
The' covers were found to be laying in the bottom back of the panel.
B.
Background:
l Refer to NCR'DC1-93-EM-N019.
C.
Event
Description:
i l
Refer to NCR DC1-93-EM-N019.
D.
Inoperable Structures, Components, or Sysdems that" Contributed to the Event':
l
.m
~~-
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l B
None..
l E.
Dates and Approximate Times for Major Occurrences:-
]
l Refer to NCR DC1-93-EM-N019.
F.
Other Systems or Secondary Functions Affected:
None.
o I
G.
Method of Discovery:
5 l
Refer to NCR DC1-93-EM-N019.
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NCR DCO-93-EM-N030 Fav. 00 June 7,'1993 t
H.
Operator Actions:
t None.
+
l I.
Safety System Responses:
None.
III. Cause of the Event j
A.
Immediate Cause:
l Refer to NCR DC1-93-EM-N019.
B.
Determination of Cause:
I j
Refer to NCR DC1-93-EM-N019.
C.
Root Cause:
i l
Refer to NCR DC1-93-EM-N019.
D.
Contributory Cause:
l Refer to NCR DC1-93-EM-N019.
l IV.
Analysis of the Event A.
Safety Analysis:
The plant design basis for post-fire safe shutdown does not require that a fire in the hot-shutdown p_ael. allow j
control of components (with control capability form the l
HSD panel) from the control. room.
The. requirements of l
10CFR50, Appendix R, require that' fire damage'be l
limited so that one train of components necessary to achieve and maintain hot shutdown be-free from fire damage.
The ability ~to safely shutdown following a worse case fire in the. hot shutdown panel fire' area.
l (fire area 5-A-4 for U1"and 5-B-4 for U2] has been evaluated as part of DCPP's compliance'with. Appendix R.
No credit has ever been taken for any barriers internal:
to the hot shutdown panel.
The Appendix-R post-fire' safe shutdown methodology assumesethat all circuitry within the fire area (not just circuitry inside the HSD) has been damaged by. fire. :Nofinternal separation within the panel has been taken credit for to ensure post-fire safe shutdown capability.
This basis'has 93NCRWP\\93EMNO30.KWR Page 3 _of 9
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I NCR DCO-93-EM-N030-kev.100' l'
fJune 7, 1993l t
been documented in Appendix 9.5A of the;FSAR-(pp. 9.5A-
)
97 and 9.5A-503).
t The ability to safely; shutdown following a fire in'thei hot shutdown panel fire' areas was enhanced'to provide a level of safety greater.than that which was approved by.
l the NRC in SSERS 23 and 31.
Circuit changes were i
implemented during'1R5/2R5 to ensure control of:ESF pumps (ASW, CCW, AFW, and CCPs) from the hot. shutdown panel following a worst case. control room / cable-spreading-room fire.
The circuit changes also' ensured that a fire-in the hot shutdown panel would not' adversely affect control of these pumps.from the 6
control room (under the original-~ design, approximately.
one-half of the pump controls ~could have~been-damaged i
by a fire'in the HSD panel)..The affected circuits at the hot shutdown panel are-normally de-energizei and-i therefore do not have a high. energy source that4could cause flashover from one component-to another-during a i
short-circuit condition.
B.
Reportability:
1 1.
Reviewed under QAP-15.B'and determined'to bes.
non-conforming in accordance with Section-2.1.2.
J Refer to NCR DCl-93-EM-N019.
~
2.
Reviewed under 10 CFR'50.72 and'10-CFR.50.73 per NUREG 1022 and determined to be not' reportable in accordance with1the guidance'provided in NUREG 1022 and associated supplements.
.n n.
Based on the safety. analysis'as described above, j
and the fact that an interal hot' shutdown panel:
fire would not affect 1the controls of the'.
components associated with the missing. covers, there is no basis per NUREG'1022 to report-this condition.
In addition; the_DCPP design' basis-does not consider concurrent fires at the hot shutdown panel and the control room / cable.
spreading room, nor does'the' design basis require consideration of a fire concurrent with aLLOCA.
j 3.
Reviewed under 10 CFR Part 21 andl determined ~that i
this problem will not require-a 10 CFR-21 report, since (a) it is being evaluated under 10 CFR 50.72/73, and (b):it does not involve defects in vendor-supplied services / spare parts in stock..
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NCR DCO-93-EM-NO30'Rev.'00-June 7, 1993 1
4.
This problem will not be reported via an INPO Nuclear Network entry.
l 5.
Reviewed under 10 CFR 50.9 and determined to'be not reportable since-this event does not have a significant implication for public health and safety or common defense and security.
6.
Reviewed under the' criteria of AP C-29 requiring the issue and approval of an OE and determined that an OE is not required.
l V.
Corrective Actions b
A.
Immediate Corrective Actions:
t l
l The internal hot shutdown panels were re-installed.
(
B.
Investigative Actions:
1.
For affected components.(i.e. located under the subject covers), determine the location of the associated mutually redundant component.
Identify the consequences of failure of;the mutually l
redundant components'on equipment operation _(i.e.
normal ops, safe shutdown, etc.).-
l RESPONSIBILITY: Van.Luven, P.
RETURN DEPARTMENT: NES Electrical Engineering Tracking JU1:
A0307850, AE #02 2.
Determine whether the mutually redundant components and associated circuits identified in AE #02 above meet the 5" separation-criteria with the covers missing.
l RESPONSIBILITY: Foat, S.
RETURN DEPARTMENT: Electrical Maintenance Tracking AR:
A0307850, AE #03 3.
Determine work history in the Unit 1 hot-shutdown panel ~since the start of 1R5.
l l
RESPONSIBILITY: Foat, S.
RETURN DEPARTMENT: Electrical Maintenance Tracking AR:
A0307850, AE #04 93NCRWP\\93EMNO30.KWR Page 5 'of 9
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.NCR.DCO-93-EM-NO30 Rev..00
' June 7, 1993 4.
Determine work. history in the Unit'2 hot shutd'wn.:
)
o panel'since the start of 2RS.
)
')
l RESPONSIBILITY: Foat, S.
RETURN
-DEPARTMENT: Electrical Maintenance' Tracking AR:
A0307850, AE #05.
5.
Determine'reportability of potentially inadequate mutually redundant circuit separation'in the hui shutdown panel.
l RESPONSIBILITY: Sisk, D.
RETURN DEPARTMENT:. Regulatory Compliance l
Tracking AR:
A0307850, AE'#06 l
6.
For e fire in the hot shutdown panel, verify'that-1 no circuits, in the main control. room,< associated with the components listed in AE 02'of this AR are affected.
Refer t'o AE 06 for associated reportability determination.
1 RESPONSIBILITY: Basu / Hentschel'.
RETURN DEPAR'IMENT: NES - Electrical Engineering Tracking AR:
A0307850, AE #07 i
C.
Corrective Action's to' Prevent. Recurrence:
l Refer to NCR DC1-93-EM-N019.
D.
Prudent Actions (not requiredfor NCR closure) l Refer'to NCR DC1-93-EM'-N019.
~"
~
i VI.
Additional Information A.
Failed Components:
None.
B.
Previous Similar Events:
l Refer to NCR DC1-93-EM-N019.
{
C.
Operating Experience Review:
l Refer to NCR DC1-93-EM-N019.
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NCR DCO-93-EM-N030 Rev. 00 June 7, 1993 D.
Trend Code:
l Refer to NCR DC1-93-EM-N019.
E.
Corrective Action Tracking:
1.
The tracking action request is A0307850.
2.
Are the correc'.'ve actions outage related?
l Refer to NCR DC1-93-EM-N019.
f F.
Footnotes and Special Comments:
l None G.
References:
1.
Initiating AR's:
Unit 1 A0307171 A0307172 Unit 2 l
2.
NCR DC1-93-EM-N019.
H.
TRG Meeting Minutes:
l On May 25, 1993, the TRG convened and considered the following:
Investigative actions were assigned to determine
~
whether any mutually redundant circuits were affected, whether separation criteria.was not met, to determine-work history within the hot shutdown panels; and to make a reportability recommendation.
During the latest refueling outage for both Unit 1 and Unit 2, modifications were made within the hot shutdown panel to prevent a fire in the control room or cable i
spreading room from affecting circuits in the hot shutdown panel.
The modification results in independent control circuit fuses for the hot shutdown panel associated circuits and the control room associated circuits.
The circuits in the hot shutdown panel are normally de-energized.
The TRG will reconvene on June 1, 1993, to discuss results of the investigative actions and to make a reportability determination.
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1 NCR DCO-93-EM-NO30 Rev. 00-June 17,z1993' On June 1, 1993, the TRG convened and considered the following:
l A work order search was performed, and.no positive q
evidence'could'be found to determine when the panel covers-were last removed. - Most likely the panels were removed during the 1R5/2R5 Appendix R modifications.
j
?
The following issues need to'be addressed:
1.
How is' panel ownership obtained.
The~ person removing the panel cover may'not be the-t person that. completes the job'and' returns'the i
equipment to its original configuration.
2.
Should work planners walk down all equipment and list every step required to.perf;rm the j
work.
~
l
'l l
Systematic walkdowns of the back of.the hot shutdown i
panels are not required for power ascension.
i Potential for controlling internal covers similar to l
the plant jumper log (i.e. document'all' covers' removed, similar to lif ted leads) was discussed.
This would i
required training of all craft. personnel to implement.
The TRG discussed reportability.
Based on the fact I
l that these circuits are normally de-energized, that the
{
i Appendix R modification recently made'to' preclude a short at the control room / cable spreading room trom af f ecting hot shutdown panel cirruits...(andevice versa),
<=
and the fact that a' fire does not need to be considered concurrent with a design basis accident; the-TRG concurred that the event was not reportable.
3 Investigative Action No. 6 was assigned to NES.to t
confirm these conclusions.
s Assuming resolution of reportability as discussed-above, the TRG concurred that this' event-should~be 1
addressed under NCR DC1-93-EM-N019,." Unit 1 4kV RHF Hinged Panel".
Both NCR's address the' failure to-return the panel to its original configuration following work related activities within the panel, and t
both NCR's have the same TRG Chairman. - It was agreed that a single NCR would best address a programmatic solution to the problem.
j 1
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'NCR DCO-93-EM-N030 Rev. 00 June 7, 1993 I.
Remarks:
None.
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