ML20067D535
| ML20067D535 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 02/07/1991 |
| From: | Wallace E TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 91-01, 91-1, R-910207, R0-910207, NUDOCS 9102130123 | |
| Download: ML20067D535 (6) | |
Text
- - _ - - - - - - -.,
e l
d TertheBSee Vahey Authonry.1101 Matket $tteet Chattauga Tennnsee 3702 FEB 071991 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C.
20555 Gentlement In the Matter of
)
Docket Nos. 50-327 Tennessee Valley Authority
)
50-328 SEQUOYAH NUCLEAR PLANT (SQN) UNITS 1 AND 2 - DOCKET NOS. 50-327 AND 50-328 - FACILITY OPERAT?NG LICENSES DPR-77 AND DPR SPECIAL i
REPORT 91 10 CFR 50, /sPPENDIX R, IN ACCORDANCE WITH LICENSE CONDITION 2 H The enclosed special report provides details regarding two conditions that were identified as consisting of noncompliance with 10 CFR 50 Appendix R requirements. The first condition involved routing of conduits with 1-hour-rated fire wrap in areas without the appropriate fire detection and automatic suppression system.
This condition was initially. reported by telephone notification at 1610 Eastern standard time (EST) on January 25, 1991, and confirmed by fat. simile on the same day in accordance with License Conditions 2.C.13.c and 2.4 of the Unit 2 i
Facility Operating License.
1 The second condition was identified as a result of the investigation of the first condition and involves conduits routed in an area with the appropriate fire detection and automatic seppression system, but without the 1-hour-rated fire wrap. This condition was initially reported by telephone notification at 1440 EST on January 31, 1991, and confirmed by g
facsimile on the same day in accordance with License Conditions 2.0.13.a and 2.4 of the Unit 2 Facility Operating License. These conditions are
' applicable to Units 1 and 2 as detailed in the enclosed report. This
' follow-up report is being submitted in accordance with Unit 2 License Condition 2.H.
I 9102130123 910207 PDR ADOCK 05000327
[
l i a2u PDR I
1
- s i
'.~
' 2 U.S. Nuclear Regulatory Commission _
f{g $7 jggj If you have any questions concerning this submittal, please telephone
' M. A. Cooper at (615) 843-8422.
- Very truly yours,
- TENNESSEEVALLEIAUTHORITY flls+
E. G. Wallace, Manager Nuclear Licensing!and i
' Regulatory Affairs-
- Enclosure-
'ce (Enclosure) -
l
~Ms. S.;C.LBlack. Deputy _ Director
~
Project Directorate 11-4 U.S. Nuclear Regulatory Commission-One White Flint. North
- 11555 Rockville Pike
.Rockville. Maryland 20852:
t Mr.:J. N. Donohew, Project Manager U.S. Nuclear Regulatory, Commission One White Flint, North 1
11555 Rockville Pike
~Rockville, Maryland 20852s
.NRC Resident Inspector s
Sequoyah Nuclear Plant 26001Igou Ferry Road-
. Soddy; Daisy, Tennessee -37379 lMr.B.'A[ Wilson,: Project' Chief.
U.S.' Nuclear Regulatory l Commission 4M Region II 101 Marietta Street, NW, Suite 2900
~ Atlanta," Georgia : 30323 6
9 i
l s
s k
I
+e A
e4-9,-
4'-+-,-
+e.,,o m..n.,
-c
-d..ri p%,,_ww
,c t -, r-w.,.
r--
g m w irerw -
-y wy gywr y. c..
g,.-
m.m.3i,w y-ggey,*-
s-g,...ye.e,%++y-ygyc*y--
r-
,e-4,,
y, w-y +,1 M.w4-
o ENCLOSURE 14-DAY FOLLOW-UP REPORT SPECIAL REPORT 91-01 DESCRIPTION OF CONDITION Condition 1 on January 24,1991, at 1850 Eastern standard time (EST) with Units 1 and 2 operating in Mode 1 at 100 percent power, Operations was notified that during a postmodification walkdown inspection to verify conduit routing dimensions, it was discovered that several Unit 1 and Unit 2 conduits wrapped with 1-hour fire wrap had been routed in areas that lacked fire suppression and detection.
This walkdown was being performed in'accordance with Sequoyah Engineering Procedure (SQEP) 67, " Interim Procedure to Control Appendix R Drawings Until a New Drawing Series is Issued," following implementation of Cycle 4 refueling outage Appendix R modifications to support accurate plotting of_the conduits on.the Appendix R sketch (ARSK) drawings. These conduits contained control circuits to the refueling water storage tank (RWST) and volume-control = tank (VCT) outlet valves; the _ outage modifications had been implemented to resolve previously identified Appendix R Interaction 120.
-Further investigation identified four additional conduits associated with the Unit 2 centrifugal charging pumps that had a 1-hour: fire wrap, but were routed in an area that did not contain fire suppression and detection. These conduits were'previously identified as Interaction 86 (in the 1984 timeframe). Rerouting and wrapping of the conduits had been completed in 1986.
Table 1 Conduits wrapped in a 1-hour-rated fire barrier, but routed in areas without adequate fire detection and an automatic fire suppression system:
Unit Interaction Conduit Cable Cable Used For 1
120 1V4003A IV4001A Control for 1-LCV-62-135 RWST outlet valve 2-120 2V4006B 2V2774A Control for 2-LCV-62-133 VCT outlet valve 2
-120-2V4012A 2V2764A' Control for 2-LCV-62-132 VCT outlet valve.
2 120 2V4012A.
2V2071A Control for 2-LCV-62-135 RWST outlet' valve 2
86 2PL3003A_
2PL3003A Control for centrifugal chang'ng pump (CCP) 1A-A room cooler 2
86 2PL3008A 2PP552A Control for CCP 2A-A 2
86 2PP550A 2PP550A Supply for CCP 2A-A
)
'2 86 2PL3001A 2PL3001A Supply for CCP 2A-A room cooler i
l
, U' nit I and 2 conduit locations are in the auxiliary building Elevation 690, j
valve gallery mezzanine. For Unit 1, the colunn lines are A3 to A4 and T to U.
For Unit 2, the column lines are A12 to A13 and T to U.
As a result of the above-identified deficiencies, Condition Adverse to Quality Report (CAQR) SQP910029 was written.
Immediate actions taken included ensuring that the areas were being covered by the hourly, roving fire watch patrols and conducting a walkdown, which determined that no significant 17vels of combustibles existed in the areas that would challenge the 1-huur-rated fire barriers.
In addition, the following controls were placed on any further design packages involving Appendix R conduits:
1.
The proposed conduit route shall be walked down before the design issuance to verify there is no potential to route through an area that lacks suppression and detection.
If potential exists, appropriate warnings and directions shall be placed on the design change authorization.
2.- The postmodification walkdowns will now be done as soon as the conduit is supported and before cable pulling activities.
3.
Other engineering disciplines will coordinate with the Sequoyah Mechanical Engineering by use of a quality information release to assure that the conduit will not enter an area that lacks suppression and detection.
Condition 2 On January 30, 1991, at 1540 EST with Unit 1 and 2 at 100 percent power, as part of'the incident investigation initiated as a result of Condition 1, evaluation and walkdown of other areas in the auxiliary building determined that several conduits were routed in areas containing adequate fire detection and suppression but were not vrapped in a 1-hour-rated fire barrier.- Tnere conduits contain power supply circuits to Units 1 and 2 source range neutron monitor noin control room (MCR) panels. These _ conduits are provided in Table 2.
Table _2 Conduits' routed in an area with adequate fire detection and automatic suppression system, but not wrapped in 1-hour-rated fire barrier material:
Unit 1
' Conduit Cable Function
.1 MC12891I IPV1311I Vital alternating-current (ac) supply to MCR Panel 1-M-13 (oource range neutron monitor) 1 MC1289II -IPV1331I Vital ac supply to MCR-Panel 1-M-13 (source range neutron monitor) 1 MC2546II IPV1311I Vital ac supply to MCR Panel 1-M-'13 (source-range neutron monitor) 1 MC2546II IPV133II Vital ac supply to MCR Panel 1-M-13 (source range neutron monitor) 2 MC130911 2PV13111 Vitel ac supply to MCR Panel 2-M-13 (source range neutron monitor) 2 MC1309II 2PV133II Vital ac supply to MCR Panel 2-M-13 (source range neutron monitor)
a V, ;,,
'i
_3 The; Units 1 and 2 conduits are located on Elevation 714 of the auxiliary 4
building defined by Columns A4 to A8 and Q to R.
The affected areas are being l
E covered by the hourly, roving fire watch. patrols.
1 CAUSE OF CONDITION-t Condition 1 i
.The apparer.t cause of this condition is a deficiency in the engineering evaluation process of.the modifications. The potential for inappropriate
- routing was not
- recognized by the' design personnel involved in the design changest.and accordingly,-inadequate guidance and requirements for routing were.provided in the design output documents.
Constructibility walkdowns did 1
not' identify-.the potential for routing conduits outside areas with detection j
- and suppression capability.- In' absence of additional requirements, y
Modifications personnel field routed the. subject conduits through-areas not containing adequate' detection and suppression. Additionally postmodification I
walkdowns were performed af ter the cables were returned to operation.
' Initial assessment of the overall Appendix R modification evaluation process-7 and procedures from both specific and overall perspectives. indicates that.
J
. weaknesses in these controls directly contributed to this condition.
The final. root'cause_ analysis:and incident investigation are still ongoing.
' Condition 2'
' The ' pparent _ cause of this condition is a personnel error in the writing of M
a gthe workplan (WP).- Contributing factors included lack of' detail regarding the
,u wrap material in the11nitial engineering change notice (ECN) and subsequent
- oversight"and poor communication-in the resolution of that-problem.
o iDuring the writing of the-WP to. implement the-ECN,' a number of notes on..
L drawings; required conduits to be wrapped with approved' material, but didinot.
specify'the type;ofl approved material to use.
The Modifications engineer L
~
. requested Nuclear Engineering to.specify the approved material.
Because of the size;of the.-Modification, work _ continued.on the writing of'WPs. The approved material to wrap.the conduits was' subsequently identifled verbally.by Nuclear Engineeringito.the Modifications engineer.' The no,tes requiring 1-hour Lfire wrap; were added toi the' WP ~except.one, which was missed.. Therefore,' the i
- application;was not'. implemented.
The missed drawing note identifies the 1 conduits listed in Table 2.-iAs a result of the lack of material definition '
the requirement:to wrap was not incorporated into the associated WP.
t OE
>ANAINSIS OF EVENT The conduits listed in Table _1 are wrapped in a 1-hour-rated fire barrier and g
-are located -in an area =that.does not have adequate detection and automatic; suppression as required in 10 CFR.50 Appendix-R.Section III.G.2.c.
The conduitsilisted in5 Table.2 are not wrapped in a 1-hour-rated fire barrier.and
,3 are loc'ated in:an area that does-have adequate detection and automatic
-~
4 isuppression as. required in 10 CFR 50, Appendix R, Section III.G.2.c.
This
<t
.special' report is being submitted as; required by Unit 2 License Condition 2.H.
j i
w.-
.. n.
~
~-
._.___._.__.,_..._.__._._-_,_.a
There are no plant systems or components considered inoperable or incapable of performing their design functions as a result of the condition described in this report. The affected areas.ere being covered by the hourly, roving fire watch patrols. This patrol provides assurance that a fire in this area would be identified so that appropriate response actions could be initiated.
Additionally, the subject areas have.very low in situ combustible loading.
The areas are also regulated by the Sequoyah transient fire load program, which ensures that the area is not arbitrarily used to store combustible material.
Based upon walkdowns of the affected areas, preliminary indications are that an unmitigated fire would not have sufficient duration to compromise the existing fire wrap during a worst-case fire.
i CORRECTIVE ACTION For immediate corrective action, it was verified thct the areas where deficiencies ware identified were being covered by the hourly, roving fire watch patrols.
An evaluation and walkdown of rooms and locations in the auxiliary buildin6 that are not provided with fire detectors and automatic fire suppression systems were performed.
No additional problems were identified.
As previously described, additional interim controls have been instituted for future design packages involving Appendix R conduits.
A detailed incident investigation is still ongoing to ensure identification of the contributing causes and necessary corrective actions to both address the specific conditions and prevent recurrence of similar Appendix R conditions.
Additionally, these conditions are being reviewed collectively with other past Appendix R deficiencies to determine if commonalities exist.
As a result of Condition 2, a field design change notice was initiated on February 6, 1991, to specify the required wrapping material and contract number..A WP has been written to wrap the conduits and will be performed once it is approved and the materials are obtained.
A supplement to this report will be provided by March 15, 1991, detailing the results of the investigation and schedule for corrective actions.
COMMITMENT l
1 TVA will provide a supplement to Special Report 91-01 by March 15, 1991, i