Text

Lr - Diablo Canyon Pull Box
	ML102710742
Person / Time
Site:	Diablo Canyon
Issue date:	07/14/2010
From:	; Pacific Gas & Electric Co
To:	; NRC Region 4
References
	Download: ML102710742 (40)
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1 DiabloCanyonNPEm Resource From:

Davis, Rigel I [RND9@pge.com]

Sent:

Wednesday, July 14, 2010 4:12 PM To:

greg.pick@nrc.gov

Subject:

Diablo Canyon Pull box Attachments:

OE white paper Electrical XI E3 Boxes.doc; Pull Box Layout.PDF Greg, Attached is the Operating Experience Whitepaper for the DCPP pullboxes, and also the pullbox layouts.

Thank you, Rye Davis PG&E License Renewal (623) 393-5225 rnd9@pge.com

<<OE white paper Electrical XI E3 Boxes.doc>> <<Pull Box Layout.PDF>>

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7/14/2010 4:12:54 PM From:

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exchange18.Utility.pge.com Files Size Date & Time MESSAGE 275 7/14/2010 4:12:54 PM OE white paper Electrical XI E3 Boxes.doc 645184 Pull Box Layout.PDF 1091515 Options Priority:

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Diablo Canyon Power Plant Operating Experience White Paper XI.E3 Inaccessible Medium Voltage Cables Not Subject to 10 CFR 50.49 Environmental Qualification Requirements Pull Boxes Subject to Water Intrusion and Collection January 30 2010

Diablo Canyon Power Plant Inaccessible Medium Voltage Cables Not Subject to 10 CFR 50.49 Requirements 1

1.0 Background

Most electrical cables in nuclear power plants are located in dry environments. However, some cables may be exposed to condensation and wetting in inaccessible locations, such as conduits, cable trenches, cable troughs, duct banks, underground vaults or direct buried installations. When an energized medium-voltage cable (2 kV to 35 kV) is exposed to wet conditions for which it is not designed, water treeing or a decrease in the dielectric strength of the conductor insulation can occur. This can potentially lead to electrical failure.

NUREG-1801 XI.E3, Medium Voltage Cable Aging Management, recommends periodic actions be taken to prevent cables from being exposed to significant moisture, such as inspecting for water collection in cable pull boxes, and draining water, as needed. The above actions are not sufficient to assure that water is not trapped elsewhere in the raceways. For example, if duct bank conduit has low points in the routing, there could be potential for long-term submergence at these low points. In addition, concrete raceways may crack due to soil settling over a long period of time and pull box covers may not be watertight. Additionally, in certain areas, the water table is high in seasonal cycles and therefore, the raceways may get refilled soon after purging.

The purpose of the white paper is to describe the Diablo Canyon Power Plant (DCPP) monitoring and preventive maintenance programs that manage the collection of water in pull boxes that contain cables within the scope of XI.E3.

2.0 Scope The program applies to inaccessible medium voltage cables within the scope of the license renewal that may be exposed to significant moisture simultaneous with significant voltage.

Table 1 provides the complete list of inaccessible medium voltage cables not subject to 10 CFR 50.49 EQ requirements within the scope of the XI.E3 aging management program.

Table 1 In Scope Cables Cable ID Unit From To F08H00A 1

BJA219 ASP1 F10H00 1

SHF10 SPF F12H00 1

SHF12 CCWP1 G06H00A 1

BJA216 ASP2 G10H00 1

SHG10 SPG G12H00 1

SHG12 CCWP2 H10H00 1

SHH10 SPH H12H00 1

SHH12 CCWP3 TUV200A1 2

SVU23 THU22 TUV200A2 2

SVU23 THU22 TUV200A3 2

SVU23 THU22

Diablo Canyon Power Plant Inaccessible Medium Voltage Cables Not Subject to 10 CFR 50.49 Requirements 2

Table 1 In Scope Cables Cable ID Unit From To TUV200B1 2

SVU23 THU22 TUV200B2 2

SVU23 THU22 TUV200B3 2

SVU23 THU22 TUV200C1 2

SVU23 THU22 TUV200C2 2

SVU23 THU22 TUV200C3 2

SVU23 THU22 F08H00A 2

BJA218 ASP1 F10H00 2

SHF10 THF10 F12H00 2

SHF12 CCWP1 G06H00A 2

BJA226 ASP2 G10H00 2

SHG10 THG10 G12H00 2

SHG12 CCWP2 H10H00 2

SHH10 THH10 H12H00 2

SHH12 CCWP3 3.0 Cable Operating Experience PG&E letter DCL-07-053 describes cable failures experienced at DCPP related to inaccessible medium voltage cables. DCPP has experienced degraded insulation in 3 inaccessible medium voltage cables not subject to 10 CFR 50.49 EQ requirements. Although the cables did not fail in service the degradation required removing the affected loads from service to expedite repairs. The medium voltage cables were Okonite black ethylene propylene rubber (EPR) with tinned copper tape shield and Neoprene jacket purchased in 1972 from Okonite.

This list identifies each of the, in scope, inaccessible medium voltage cables that experienced in service degradation included in this program:

Date of Event Circuit Number Service to Voltage October 29, 1989 G06H00 ASW 2-2 4 kV October 31, 1992 G06H00 ASW 1-2 4 kV August 18, 2002 H12H00 CCW 2-3 4 kV As discussed in DCL-07-053, definitive evidence of the causes of the failures of the cables to ASW 2-2 and ASW 1-2 was not found but DCPP suspects that water may have been a contributing factor to the degradation of the cable. The degradation of the CCW2-3 cable was attributed to discrete contaminant particles within the insulation material. Additionally 7 other cables failed to meet the acceptance criteria when tested. As a result of this determination, all original safety-related medium voltage cables have been replaced. (Corrective actions for Non Conformance Report (NCR) N0002150) Replacement cable is modern red EPR with tinned copper tape shield and Hypalon jacket.

Diablo Canyon Power Plant Inaccessible Medium Voltage Cables Not Subject to 10 CFR 50.49 Requirements 3

4.0 Preventive Programs As a result of the observed medium voltage cable degradation attributed at least in part to the presence of water, DCPP established outdoor electrical pull box water inspections in which pull boxes are pumped out to a maximum depth of 4 inches if water is found, drains are cleaned, and sump pumps and alarms are inspected. The inspection frequency is performed based on actual plant experience with water accumulation. In addition to water inspection of the electrical pull boxes, DCPP established a duct bank conduits inspection for the presence of water trapped behind conduit seals at the entrance of the building or due to being present in dips in the conduit where water does not drain as designed. Any conduit found with water is drained and monitored to verify that water does not return. The following is a summary of these programs.

4.1 Pull boxes in-scope Table 3 provides a listing of the pull boxes within the scope of AMP XI.E3.

4.2 Pull Box inspections 4.2.1 Indoor Pull Boxes During the cable replacement program the conduits were dried, cleaned, and inspected. Operating experience demonstrates that indoor pull boxes, in the auxiliary building and turbine buildings, are not subject to water intrusion. Electrical indoor pull boxes are not periodically inspected; however, some of the outdoor conduits entering these boxes were included in the conduit inspection population. Some conduits have been inspected for water collection, where cables do not obstruct access to the conduits.

Electrical pull boxes BPG01-BPG06 are located in the auxiliary building (Area GW) and are not subject to water intrusion and accumulation. These pull boxes are designed with a drain in case water gets inside the pull boxes. Refer to drawing 57597 for Unit 1 and drawing 500732 for Unit 2.

Electrical pull boxes BPO1-BPO11are located in the turbine building and are not subject to water intrusion and accumulation. These pull boxes are above floor level and are not structurally capable of retaining large accumulations of water. Additionally holes penetrate the fire barriers that separate the pull boxes from the room and each other.

Drains have a downward slope that allows water to flow to a trench that collects the water from pull boxes and drains to a sump pit. Refer to drawing 438331 for Unit 1 and drawing 500606 for Unit 2.

4.2.2 Outdoor Pull Boxes As a result of plant operating experience, with medium voltage cable degradation, DCPP created several programs to mitigate submergence of safety-related cables. All Pull boxes containing safety related medium voltage cable, located outdoors, are inspected for standing water. This includes all in scope medium voltage outdoor pull boxes. If more than 4 inches of water is found

Diablo Canyon Power Plant Inaccessible Medium Voltage Cables Not Subject to 10 CFR 50.49 Requirements 4

in any pull box, it is pumped out to a maximum depth of 4 inches. The water pump is not capable of removing water from the pull box if it is less than 4 inches deep.

Pull boxes BPO13 to BPO20, located outside the Turbine Building, have been designed with a drain that prevents standing water in the pull box. Drained water flows through a conduit to a sump pump in a man hole adjacent to BPO13. Some instances of water accumulation have been documented. A high water level alarm on Unit 1 was reported on 11/11/1997. A visual inspection verified the high water level. The pull box sump was pumped out as a result of the alarm. On 10/17/2002 BPO13 for Unit 1 was discovered to have about 2 of standing water. The alarm failed to signal which led to the discovery of improper switch settings. As a result the actuation level for the alarm was reset. On 01/29/2003 both Unit 1 and Unit 2 BPO13 pull boxes contained water. Cables, not in the scope of license renewal, in both boxes were found submerged. Inspection indicated that the float for the alarm in Unit 1 was set significantly higher than it should be, resulting in no alarm until the cables were submerged. Action was taken to reset the levels on the alarm to the appropriate settings. A Unit 1 Sump Pump high level alarm on 11/11/2003 led to the discovery of 3 of water in the sump. The discharge line was blocked and the pump failed. As a result the discharge line was cleared and Manhole Sump Pump 1 was replaced. As of the last documented incident no alarms or pump failures have occurred, and the regularly scheduled maintenance is performed.

These pull boxes are regularly scheduled for inspection by RT 47369 (now maintenance plan 12800). During the dry season the system engineer can waive the inspection requirements. The sump pumps are inspected by RT 44855 (MP 12291) and RT 544858 (MP 18436) once per year refer to Table 6 and 7. Refer to drawing 438168 for Unit 1 and drawing 443001 for Unit 2.

The remainder of the pull boxes, between the Turbine Building and Intake Structure including those within the scope of the XI.E3 program, are grouped in sets of pull boxes, for each unit. Every set of pull boxes is interconnected with a drainage gutter that collects water in a sump. The inspection program inspects, and if necessary pumps, the box with the inspection port. The cover for one box in each set of these boxes is provided with an access hole and cover for the purpose of inspection and pumping per the recurring task.

RT 47369 (MP 12800) schedules inspection of these boxes every 2 months. The inspections can be deferred by the system engineer during the dry season and are conducted during the rainy season for indications of water intrusion. Pull boxes at the Intake Structure, BPZ40 to BPZ44, are designed with a drain to remove water. These pull boxes are inspected by RT 47399 (MP 12814) and RT 547399 (MP 18790) every other refueling outage. The drains are routed to the Intake sump. Refer to drawing 500817 for Unit 1 and drawing 500692 for Unit 2.

PGE Letter DCL-07-053 describes DCPP water intrusion inspections that are performed periodically to minimize or eliminate wet conditions.

4.3 Results of medium voltage pull box water inspections The inspection and dewatering program at DCPP has been effective in keeping the pull boxes dry.

Diablo Canyon Power Plant Inaccessible Medium Voltage Cables Not Subject to 10 CFR 50.49 Requirements 5

Table 2 lists all medium voltage pull box inspections scheduled from January 2000 thru January 2010. It identifies the inspections where water depth exceeded the maximum allowable for any pull box in the inspection. All in scope pull boxes are part of each inspection.

Table 3 provides the results of water inspections for all pull boxes within the scope of XI.E3. The table lists the work orders and where water collection was found in pull boxes in the scope of the XI.E3 aging management program. The period covers the time frame from January 2000 to January 2010.

4.4 One time inspection of duct bank conduits for presence of water NCR 2188 corrective actions require the inspection of underground conduits, containing Raychem XLPE cables, suspected of containing water. The inspection looks for the presence of water and removes any water that is found. The conduit seals will also be removed, if possible, to dry out any water that may be located in dips in the conduits. If the seal cannot be removed a vent path is provided, if possible. Any conduits found to contain water will be monitored to verify the water does not return.

After inspection of the conduits is complete, one more inspection will be scheduled for conduits where water was found to verify that water has not returned to these conduits. If water is found in conduits, DCPP will conduct subsequent inspections to establish whether water intrusion is a recurrent problem. Table 4 shows the results of conduit inspections for inaccessible medium voltage cables not subject to 10 CFR 50.49 EQ requirements.

5.0 Conclusion DCPP established a Safety Related medium voltage cable replacement program to ensure operability of the cable at the plant per NCR N0002150.

DCPP has several programs currently in place to minimize safety-related cable submergence.

The plant performs pull box inspections and dewatering preventive maintenance for 4kV and 12kV underground electrical circuits located between the Turbine Building and the Intake Structure.

In the past DCPP experienced several water accumulation issues relating to the Sump Pumps.

Appropriate action was taken to resolve these issues. As of 11/11/2003 no alarms or pump failures have occurred. The functionality and condition of sump pumps are verified annually.

The existing maintenance and inspection activities have been effective in limiting the exposure of in scope medium voltage cables to significant moisture. No water accumulation has been noted since spring of 2005, and no cables have been submerged, in pull boxes, for at least the last 10 years.

Experience has shown that the inspection programs established by DCPP have been effective in ensuring that medium voltage cables are not exposed to significant moisture. The operability of

Diablo Canyon Power Plant Inaccessible Medium Voltage Cables Not Subject to 10 CFR 50.49 Requirements 6

in scope medium voltage cables will not be adversely affected by long term exposure to water collecting in associated pull boxes.

6. Open Items 6.1. Intake work plans change to 24 months or each cycle.

6.2. System Engineer will add a note to the RT 47369(Work Plan 12800) which will create a notification if water level found in the pull boxes is greater than 4 inches.

6.3. Determine completion date for conduit inspection.

6.4. Restore requirement to write notification if pumping is required - document cables / conduits covered (Y/N).

7 Reference 8.1 The following listing of drawing shows the construction configuration of pull boxes: drawings 437890, 438114, 438115, 438116, and 500820 (Unit 1) and drawings 443002, 500616, 438113 and 500820 (Unit 2). Unit 1 contains 3 sets of pull boxes between the Discharge Structure and the Intake Structure. The first set, located at coordinate D2 drawing 522196, consist of pull boxes BPO21, BPO39, BPO29 and BPO23. The second and third sets of pull boxes are located at coordinate C3. Pull boxes BPO22, BPO38, BPO35 and BPO34 are part of the second set of pull boxes and the third set consist of pull boxes BPO45, BPO44, BPO43 and BPO42. Unit 2 contains 2 sets of pull boxes, between the Discharge and Intake Structure, located at C4 (drawing 522196). The first set groups pull boxes BPO35, BPO34, BPO33 and BPO32. The second set contains pull boxes BPO45, BPO44, BPO43 and BPO42.

Diablo Canyon Power Plant Inaccessible Medium Voltage Cables Not Subject to 10 CFR 50.49 Requirements 1

Table 2 Scheduled Pull boxes Inspections Date W/O number Water found

1.

2/18/00 R0203085 X

2.

5/24/00 R0205679 X

3.

07/12/00 R0208635 X

4.

9/6/00 R0209950 X

5.

2/2/01 R0211299 X

6.

4/13/01 R0217363 X

7.

6/26/01 R0219539 X

8.

8/23/01 R0223149

9.

10/24/01 R0224833 10 1/11/02 R0226821 X

11 4/26/02 R0228766 X

12 6/28/02 R0234755 13 8/27/02 R0236993 14 11/4/02 R0237255 15 1/14/03 R0239570 X

16 3/10/03 R0241180 X

17 5/13/03 R0244457 18 7/9/03 R0246571 19 9/2/03 R0248466 20 10/30/03 R0251555 21 1/27/04 R0252516 22 3/20/04 R0255453 X

23 7/16/04 R0257215 24 9/7/04 R0262838 25 10/25/04 R0264451 X

26 12/17/04 R0266340 X

27 2/10/05 R0269608 X

28 4/5/05 R0271478 X

29 6/7/05 R0273110 30 10/21/05 R0274662 31 12/15/05 R0278757 32 1/12/06 R0282500 33 3/24/06 R0283292 34 6/2/06 R0285639 35 7/27/06 R0289865

Diablo Canyon Power Plant Inaccessible Medium Voltage Cables Not Subject to 10 CFR 50.49 Requirements 2

36 9/26/06 R0291715 37 1/18/07 R0295322 38 3/22/07 R0298946 39 5/18/07 R0299225 40 7/12/07 R0401442 41 10/29/07 R0304519 42 12/26/07 R0308033 43 2/27/08 R0310592 44 4/21/08 R0312775 45 6/11/08 R0315984 46 7/29/08 R0318599 47 10/20/08 R0319908 48 9/28/08 50067928 64022497 49 3/24/09 50067929 64022498 50 6/2/09 50067930 64022499 51 7/20/09 50067932 64022500 52 9/28/09 50067933 64022502 53 11/9/09 50094526 64029736 54 1/4/10 50197704 64032054

2009 Results not yet available from RMS. Per planner no water was required to be pumped in 2009. This is expected due to extended dry period.

Diablo Canyon Power Plant Inaccessible Medium Voltage Cables Not Subject to 10 CFR 50.49 Requirements 1

Table 3 Inspection Results for In-Scope Pull Boxes only Unit Pull Box RT/Work Order Date Water Found No Water Comments 1

BP013 R0203085 R0205679 R0208635 R0209950 R0211299 R0217363 R0219539 R0223149 R0224833 R0226821 R0228766 R0234755 R0236993 R0237255 R0239570 R0241180 R0244457 R0246571 R0248466 R0251555 R0252516 R0255453 R0257215 R0262838 R0264451 R0266340 R0269608 R0271478 R0273110 R0274662 R0278757 R0282500 R0283292 R0285639 R0289865 R0291715 R0295322 2/18/00 5/24/00 7/12/00 9/6/00 2/02/01 4/13/01 6/26/01 8/23/01 10/24/01 1/11/02 4/26/02 6/28/02 8/27/02 11/4/02 1/14/03 3/10/03 5/13/03 7/9/03 9/2/03 10/30/03 1/27/04 3/20/04 7/16/04 9/7/04 10/25/04 12/17/04 2/10/05 4/5/05 6/7/05 10/21/05 12/15/05 1/12/06 3/24/06 6/2/06 7/27/06 9/26/06 1/18/07 X

X X

Diablo Canyon Power Plant Inaccessible Medium Voltage Cables Not Subject to 10 CFR 50.49 Requirements 2

Unit Pull Box RT/Work Order Date Water Found No Water Comments R0298946 R0299225 R0401442 R0304519 R0308033 R0310592 R0312775 R0315984 R0318599 R0319908 50067928 64022497 50067929 64022498 50067930 64022499 50067932 64022500 50067933 64022502 50094526 64029736 50197704 64032054 3/22/07 5/18/07 7/12/07 10/29/07 12/26/07 2/27/08 4/21/08 6/11/08 7/29/08 10/20/08 9/28/08 3/24/09 6/2/09 7/20/09 9/28/09 11/9/09 1/4/10 X

X X

1 BP016 R0203085 R0205679 R0208635 R0209950 R0211299 R0217363 R0219539 R0223149 R0224833 R0226821 R0228766 R0234755 R0236993 R0237255 R0239570 R0241180 2/18/00 5/24/00 7/12/00 9/6/00 2/02/01 4/13/01 6/26/01 8/23/01 10/24/01 1/11/02 4/26/02 6/28/02 8/27/02 11/4/02 1/14/03 3/10/03 X

X X

X

Diablo Canyon Power Plant Inaccessible Medium Voltage Cables Not Subject to 10 CFR 50.49 Requirements 3

Unit Pull Box RT/Work Order Date Water Found No Water Comments R0244457 R0246571 R0248466 R0251555 R0252516 R0255453 R0257215 R0262838 R0264451 R0266340 R0269608 R0271478 R0273110 R0274662 R0278757 R0282500 R0283292 R0285639 R0289865 R0291715 R0295322 R0298946 R0299225 R0401442 R0304519 R0308033 R0310592 R0312775 R0315984 R0318599 R0319908 50067928 64022497 50067929 64022498 50067930 64022499 50067932 64022500 50067933 64022502 5/13/03 7/9/03 9/2/03 10/30/03 1/27/04 3/20/04 7/16/04 9/7/04 10/25/04 12/17/04 2/10/05 4/5/05 6/7/05 10/21/05 12/15/05 1/12/06 3/24/06 6/2/06 7/27/06 9/26/06 1/18/07 3/22/07 5/18/07 7/12/07 10/29/07 12/26/07 2/27/08 4/21/08 6/11/08 7/29/08 10/20/08 9/28/08 3/24/09 6/2/09 7/20/09 9/28/09 X

X X

X

Diablo Canyon Power Plant Inaccessible Medium Voltage Cables Not Subject to 10 CFR 50.49 Requirements 4

Unit Pull Box RT/Work Order Date Water Found No Water Comments 50094526 64029736 50197704 64032054 11/9/09 1/4/10 X

X 1

BP019 R0203085 R0205679 R0208635 R0209950 R0211299 R0217363 R0219539 R0223149 R0224833 R0226821 R0228766 R0234755 R0236993 R0237255 R0239570 R0241180 R0244457 R0246571 R0248466 R0251555 R0252516 R0255453 R0257215 R0262838 R0264451 R0266340 R0269608 R0271478 R0273110 R0274662 R0278757 R0282500 R0283292 R0285639 R0289865 R0291715 R0295322 2/18/00 5/24/00 7/12/00 9/6/00 2/02/01 4/13/01 6/26/01 8/23/01 10/24/01 1/11/02 4/26/02 6/28/02 8/27/02 11/4/02 1/14/03 3/10/03 5/13/03 7/9/03 9/2/03 10/30/03 1/27/04 3/20/04 7/16/04 9/7/04 10/25/04 12/17/04 2/10/05 4/5/05 6/7/05 10/21/05 12/15/05 1/12/06 3/24/06 6/2/06 7/27/06 9/26/06 1/18/07 X

X X

Diablo Canyon Power Plant Inaccessible Medium Voltage Cables Not Subject to 10 CFR 50.49 Requirements 5

Unit Pull Box RT/Work Order Date Water Found No Water Comments R0298946 R0299225 R0401442 R0304519 R0308033 R0310592 R0312775 R0315984 R0318599 R0319908 50067928 64022497 50067929 64022498 50067930 64022499 50067932 64022500 50067933 64022502 50094526 64029736 50197704 64032054 3/22/07 5/18/07 7/12/07 10/29/07 12/26/07 2/27/08 4/21/08 6/11/08 7/29/08 10/20/08 9/28/08 3/24/09 6/2/09 7/20/09 9/28/09 11/9/09 1/4/10 X

X X

1 BP025 R0203085 R0205679 R0208635 R0209950 R0211299 R0217363 R0219539 R0223149 R0224833 R0226821 R0228766 R0234755 R0236993 R0237255 R0239570 R0241180 R0244457 2/18/00 5/24/00 7/12/00 9/6/00 2/02/01 4/13/01 6/26/01 8/23/01 10/24/01 1/11/02 4/26/02 6/28/02 8/27/02 11/4/02 1/14/03 3/10/03 5/13/03 X

X X

(1)

(2)

>12" (3)

>12" (4)

Diablo Canyon Power Plant Inaccessible Medium Voltage Cables Not Subject to 10 CFR 50.49 Requirements 6

Unit Pull Box RT/Work Order Date Water Found No Water Comments R0246571 R0248466 R0251555 R0252516 R0255453 R0257215 R0262838 R0264451 R0266340 R0269608 R0271478 R0273110 R0274662 R0278757 R0282500 R0283292 R0285639 R0289865 R0291715 R0295322 R0298946 R0299225 R0401442 R0304519 R0308033 R0310592 R0312775 R0315984 R0318599 R0319908 50067928 64022497 50067929 64022498 50067930 64022499 50067932 64022500 50067933 64022502 50094526 64029736 7/9/03 9/2/03 10/30/03 1/27/04 3/20/04 7/16/04 9/7/04 10/25/04 12/17/04 2/10/05 4/5/05 6/7/05 10/21/05 12/15/05 1/12/06 3/24/06 6/2/06 7/27/06 9/26/06 1/18/07 3/22/07 5/18/07 7/12/07 10/29/07 12/26/07 2/27/08 4/21/08 6/11/08 7/29/08 10/20/08 9/28/08 3/24/09 6/2/09 7/20/09 9/28/09 11/9/09 X

X X

X

Diablo Canyon Power Plant Inaccessible Medium Voltage Cables Not Subject to 10 CFR 50.49 Requirements 7

Unit Pull Box RT/Work Order Date Water Found No Water Comments 50197704 64032054 1/4/10 X

1 BP029C R0203085 R0205679 R0208635 R0209950 R0211299 R0217363 R0219539 R0223149 R0224833 R0226821 R0228766 R0234755 R0236993 R0237255 R0239570 R0241180 R0244457 R0246571 R0248466 R0251555 R0252516 R0255453 R0257215 R0262838 R0264451 R0266340 R0269608 R0271478 R0273110 R0274662 R0278757 R0282500 R0283292 R0285639 R0289865 R0291715 R0295322 R0298946 R0299225 2/18/00 5/24/00 7/12/00 9/6/00 2/02/01 4/13/01 6/26/01 8/23/01 10/24/01 1/11/02 4/26/02 6/28/02 8/27/02 11/4/02 1/14/03 3/10/03 5/13/03 7/9/03 9/2/03 10/30/03 1/27/04 3/20/04 7/16/04 9/7/04 10/25/04 12/17/04 2/10/05 4/5/05 6/7/05 10/21/05 12/15/05 1/12/06 3/24/06 6/2/06 7/27/06 9/26/06 1/18/07 3/22/07 5/18/07 X

X X

Diablo Canyon Power Plant Inaccessible Medium Voltage Cables Not Subject to 10 CFR 50.49 Requirements 8

Unit Pull Box RT/Work Order Date Water Found No Water Comments R0401442 R0304519 R0308033 R0310592 R0312775 R0315984 R0318599 R0319908 50067928 64022497 50067929 64022498 50067930 64022499 50067932 64022500 50067933 64022502 50094526 64029736 50197704 64032054 7/12/07 10/29/07 12/26/07 2/27/08 4/21/08 6/11/08 7/29/08 10/20/08 9/28/08 3/24/09 6/2/09 7/20/09 9/28/09 11/9/09 1/4/10 X

X X

1 BPO35C BP038B R0203085 R0205679 R0208635 R0209950 R0211299 R0217363 R0219539 R0223149 R0224833 R0226821 R0228766 R0234755 R0236993 R0237255 R0239570 R0241180 R0244457 R0246571 R0248466 2/18/00 5/24/00 7/12/00 9/6/00 2/02/01 4/13/01 6/26/01 8/23/01 10/24/01 1/11/02 4/26/02 6/28/02 8/27/02 11/4/02 1/14/03 3/10/03 5/13/03 7/9/03 9/2/03 X

X X

(1)

Diablo Canyon Power Plant Inaccessible Medium Voltage Cables Not Subject to 10 CFR 50.49 Requirements 9

Unit Pull Box RT/Work Order Date Water Found No Water Comments R0251555 R0252516 R0255453 R0257215 R0262838 R0264451 R0266340 R0269608 R0271478 R0273110 R0274662 R0278757 R0282500 R0283292 R0285639 R0289865 R0291715 R0295322 R0298946 R0299225 R0401442 R0304519 R0308033 R0310592 R0312775 R0315984 R0318599 R0319908 50067928 64022497 50067929 64022498 50067930 64022499 50067932 64022500 50067933 64022502 50094526 64029736 50197704 64032054 10/30/03 1/27/04 3/20/04 7/16/04 9/7/04 10/25/04 12/17/04 2/10/05 4/5/05 6/7/05 10/21/05 12/15/05 1/12/06 3/24/06 6/2/06 7/27/06 9/26/06 1/18/07 3/22/07 5/18/07 7/12/07 10/29/07 12/26/07 2/27/08 4/21/08 6/11/08 7/29/08 10/20/08 9/28/08 3/24/09 6/2/09 7/20/09 9/28/09 11/9/09 1/4/10 X

X X

Diablo Canyon Power Plant Inaccessible Medium Voltage Cables Not Subject to 10 CFR 50.49 Requirements 10 Unit Pull Box RT/Work Order Date Water Found No Water Comments 1

BPO39B R0203085 R0205679 R0208635 R0209950 R0211299 R0217363 R0219539 R0223149 R0224833 R0226821 R0228766 R0234755 R0236993 R0237255 R0239570 R0241180 R0244457 R0246571 R0248466 R0251555 R0252516 R0255453 R0257215 R0262838 R0264451 R0266340 R0269608 R0271478 R0273110 R0274662 R0278757 R0282500 R0283292 R0285639 R0289865 R0291715 R0295322 R0298946 R0299225 R0401442 R0304519 R0308033 2/18/00 5/24/00 7/12/00 9/6/00 2/02/01 4/13/01 6/26/01 8/23/01 10/24/01 1/11/02 4/26/02 6/28/02 8/27/02 11/4/02 1/14/03 3/10/03 5/13/03 7/9/03 9/2/03 10/30/03 1/27/04 3/20/04 7/16/04 9/7/04 10/25/04 12/17/04 2/10/05 4/5/05 6/7/05 10/21/05 12/15/05 1/12/06 3/24/06 6/2/06 7/27/06 9/26/06 1/18/07 3/22/07 5/18/07 7/12/07 10/29/07 12/26/07 X

X X

X

Diablo Canyon Power Plant Inaccessible Medium Voltage Cables Not Subject to 10 CFR 50.49 Requirements 11 Unit Pull Box RT/Work Order Date Water Found No Water Comments R0310592 R0312775 R0315984 R0318599 R0319908 50067928 64022497 50067929 64022498 50067930 64022499 50067932 64022500 50067933 64022502 50094526 64029736 50197704 64032054 2/27/08 4/21/08 6/11/08 7/29/08 10/20/08 9/28/08 3/24/09 6/2/09 7/20/09 9/28/09 11/9/09 1/4/10 X

X X

X 1

BP043C BP044B R0203085 R0205679 R0208635 R0209950 R0211299 R0217363 R0219539 R0223149 R0224833 R0226821 R0228766 R0234755 R0236993 R0237255 R0239570 R0241180 R0244457 R0246571 R0248466 R0251555 R0252516 R0255453 2/18/00 5/24/00 7/12/00 9/6/00 2/02/01 4/13/01 6/26/01 8/23/01 10/24/01 1/11/02 4/26/02 6/28/02 8/27/02 11/4/02 1/14/03 3/10/03 5/13/03 7/9/03 9/2/03 10/30/03 1/27/04 3/20/04 X

X X

X (1)

Diablo Canyon Power Plant Inaccessible Medium Voltage Cables Not Subject to 10 CFR 50.49 Requirements 12 Unit Pull Box RT/Work Order Date Water Found No Water Comments R0257215 R0262838 R0264451 R0266340 R0269608 R0271478 R0273110 R0274662 R0278757 R0282500 R0283292 R0285639 R0289865 R0291715 R0295322 R0298946 R0299225 R0401442 R0304519 R0308033 R0310592 R0312775 R0315984 R0318599 R0319908 50067928 64022497 50067929 64022498 50067930 64022499 50067932 64022500 50067933 64022502 50094526 64029736 50197704 64032054 7/16/04 9/7/04 10/25/04 12/17/04 2/10/05 4/5/05 6/7/05 10/21/05 12/15/05 1/12/06 3/24/06 6/2/06 7/27/06 9/26/06 1/18/07 3/22/07 5/18/07 7/12/07 10/29/07 12/26/07 2/27/08 4/21/08 6/11/08 7/29/08 10/20/08 9/28/08 3/24/09 6/2/09 7/20/09 9/28/09 11/9/09 1/4/10 X

X X

X 1

BPZ42 R0272915 R0280284 11/18/05 05/04/07 X

X

Diablo Canyon Power Plant Inaccessible Medium Voltage Cables Not Subject to 10 CFR 50.49 Requirements 13 Unit Pull Box RT/Work Order Date Water Found No Water Comments 1

BPZ43 R0272915 R0280284 11/18/05 05/04/07 X

X 2

BP013 R0203085 R0205679 R0208635 R0209950 R0211299 R0217363 R0219539 R0223149 R0224833 R0226821 R0228766 R0234755 R0236993 R0237255 R0239570 R0241180 R0244457 R0246571 R0248466 R0251555 R0252516 R0255453 R0257215 R0262838 R0264451 R0266340 R0269608 R0271478 R0273110 R0274662 R0278757 R0282500 R0283292 R0285639 R0289865 R0291715 R0295322 R0298946 R0299225 R0401442 2/18/00 5/24/00 7/12/00 9/6/00 2/02/01 4/13/01 6/26/01 8/23/01 10/24/01 1/11/02 4/26/02 6/28/02 8/27/02 11/4/02 1/14/03 3/10/03 5/13/03 7/9/03 9/2/03 10/30/03 1/27/04 3/20/04 7/16/04 9/7/04 10/25/04 12/17/04 2/10/05 4/5/05 6/7/05 10/21/05 12/15/05 1/12/06 3/24/06 6/2/06 7/27/06 9/26/06 1/18/07 3/22/07 5/18/07 7/12/07 X

X X

X (1)

(2)

Diablo Canyon Power Plant Inaccessible Medium Voltage Cables Not Subject to 10 CFR 50.49 Requirements 14 Unit Pull Box RT/Work Order Date Water Found No Water Comments R0304519 R0308033 R0310592 R0312775 R0315984 R0318599 R0319908 50067928 64022497 50067929 64022498 50067930 64022499 50067932 64022500 50067933 64022502 50094526 64029736 50197704 64032054 10/29/07 12/26/07 2/27/08 4/21/08 6/11/08 7/29/08 10/20/08 9/28/08 3/24/09 6/2/09 7/20/09 9/28/09 11/9/09 1/4/10 X

X X

X 2

BP016 R0203085 R0205679 R0208635 R0209950 R0211299 R0217363 R0219539 R0223149 R0224833 R0226821 R0228766 R0234755 R0236993 R0237255 R0239570 R0241180 R0244457 R0246571 R0248466 R0251555 2/18/00 5/24/00 7/12/00 9/6/00 2/02/01 4/13/01 6/26/01 8/23/01 10/24/01 1/11/02 4/26/02 6/28/02 8/27/02 11/4/02 1/14/03 3/10/03 5/13/03 7/9/03 9/2/03 10/30/03 X

X X

X

Diablo Canyon Power Plant Inaccessible Medium Voltage Cables Not Subject to 10 CFR 50.49 Requirements 15 Unit Pull Box RT/Work Order Date Water Found No Water Comments R0252516 R0255453 R0257215 R0262838 R0264451 R0266340 R0269608 R0271478 R0273110 R0274662 R0278757 R0282500 R0283292 R0285639 R0289865 R0291715 R0295322 R0298946 R0299225 R0401442 R0304519 R0308033 R0310592 R0312775 R0315984 R0318599 R0319908 50067928 64022497 50067929 64022498 50067930 64022499 50067932 64022500 50067933 64022502 50094526 64029736 50197704 64032054 1/27/04 3/20/04 7/16/04 9/7/04 10/25/04 12/17/04 2/10/05 4/5/05 6/7/05 10/21/05 12/15/05 1/12/06 3/24/06 6/2/06 7/27/06 9/26/06 1/18/07 3/22/07 5/18/07 7/12/07 10/29/07 12/26/07 2/27/08 4/21/08 6/11/08 7/29/08 10/20/08 9/28/08 3/24/09 6/2/09 7/20/09 9/28/09 11/9/09 1/4/10 X

X X

X

Diablo Canyon Power Plant Inaccessible Medium Voltage Cables Not Subject to 10 CFR 50.49 Requirements 16 Unit Pull Box RT/Work Order Date Water Found No Water Comments 2

BP019 R0203085 R0205679 R0208635 R0209950 R0211299 R0217363 R0219539 R0223149 R0224833 R0226821 R0228766 R0234755 R0236993 R0237255 R0239570 R0241180 R0244457 R0246571 R0248466 R0251555 R0252516 R0255453 R0257215 R0262838 R0264451 R0266340 R0269608 R0271478 R0273110 R0274662 R0278757 R0282500 R0283292 R0285639 R0289865 R0291715 R0295322 R0298946 R0299225 R0401442 R0304519 R0308033 2/18/00 5/24/00 7/12/00 9/6/00 2/02/01 4/13/01 6/26/01 8/23/01 10/24/01 1/11/02 4/26/02 6/28/02 8/27/02 11/4/02 1/14/03 3/10/03 5/13/03 7/9/03 9/2/03 10/30/03 1/27/04 3/20/04 7/16/04 9/7/04 10/25/04 12/17/04 2/10/05 4/5/05 6/7/05 10/21/05 12/15/05 1/12/06 3/24/06 6/2/06 7/27/06 9/26/06 1/18/07 3/22/07 5/18/07 7/12/07 10/29/07 12/26/07 X

X X

X

>12" 5"

Diablo Canyon Power Plant Inaccessible Medium Voltage Cables Not Subject to 10 CFR 50.49 Requirements 17 Unit Pull Box RT/Work Order Date Water Found No Water Comments R0310592 R0312775 R0315984 R0318599 R0319908 50067928 64022497 50067929 64022498 50067930 64022499 50067932 64022500 50067933 64022502 50094526 64029736 50197704 64032054 2/27/08 4/21/08 6/11/08 7/29/08 10/20/08 9/28/08 3/24/09 6/2/09 7/20/09 9/28/09 11/9/09 1/4/10 X

X X

X 2

BP025 R0203085 R0205679 R0208635 R0209950 R0211299 R0217363 R0219539 R0223149 R0224833 R0226821 R0228766 R0234755 R0236993 R0237255 R0239570 R0241180 R0244457 R0246571 R0248466 R0251555 R0252516 R0255453 2/18/00 5/24/00 7/12/00 9/6/00 2/02/01 4/13/01 6/26/01 8/23/01 10/24/01 1/11/02 4/26/02 6/28/02 8/27/02 11/4/02 1/14/03 3/10/03 5/13/03 7/9/03 9/2/03 10/30/03 1/27/04 3/20/04 X

X X

X (1)

(1)

(2)

>12" (3)

Diablo Canyon Power Plant Inaccessible Medium Voltage Cables Not Subject to 10 CFR 50.49 Requirements 18 Unit Pull Box RT/Work Order Date Water Found No Water Comments R0257215 R0262838 R0264451 R0266340 R0269608 R0271478 R0273110 R0274662 R0278757 R0282500 R0283292 R0285639 R0289865 R0291715 R0295322 R0298946 R0299225 R0401442 R0304519 R0308033 R0310592 R0312775 R0315984 R0318599 R0319908 50067928 64022497 50067929 64022498 50067930 64022499 50067932 64022500 50067933 64022502 50094526 64029736 50197704 64032054 7/16/04 9/7/04 10/25/04 12/17/04 2/10/05 4/5/05 6/7/05 10/21/05 12/15/05 1/12/06 3/24/06 6/2/06 7/27/06 9/26/06 1/18/07 3/22/07 5/18/07 7/12/07 10/29/07 12/26/07 2/27/08 4/21/08 6/11/08 7/29/08 10/20/08 9/28/08 3/24/09 6/2/09 7/20/09 9/28/09 11/9/09 1/4/10 X

X X

X 2

BP033 BP033A R0203085 R0205679 2/18/00 5/24/00 X

X (1)

Diablo Canyon Power Plant Inaccessible Medium Voltage Cables Not Subject to 10 CFR 50.49 Requirements 19 Unit Pull Box RT/Work Order Date Water Found No Water Comments R0208635 R0209950 R0211299 R0217363 R0219539 R0223149 R0224833 R0226821 R0228766 R0234755 R0236993 R0237255 R0239570 R0241180 R0244457 R0246571 R0248466 R0251555 R0252516 R0255453 R0257215 R0262838 R0264451 R0266340 R0269608 R0271478 R0273110 R0274662 R0278757 R0282500 R0283292 R0285639 R0289865 R0291715 R0295322 R0298946 R0299225 R0401442 R0304519 R0308033 R0310592 R0312775 7/12/00 9/6/00 2/02/01 4/13/01 6/26/01 8/23/01 10/24/01 1/11/02 4/26/02 6/28/02 8/27/02 11/4/02 1/14/03 3/10/03 5/13/03 7/9/03 9/2/03 10/30/03 1/27/04 3/20/04 7/16/04 9/7/04 10/25/04 12/17/04 2/10/05 4/5/05 6/7/05 10/21/05 12/15/05 1/12/06 3/24/06 6/2/06 7/27/06 9/26/06 1/18/07 3/22/07 5/18/07 7/12/07 10/29/07 12/26/07 2/27/08 4/21/08 X

X X

X

Diablo Canyon Power Plant Inaccessible Medium Voltage Cables Not Subject to 10 CFR 50.49 Requirements 20 Unit Pull Box RT/Work Order Date Water Found No Water Comments R0315984 R0318599 R0319908 50067928 64022497 50067929 64022498 50067930 64022499 50067932 64022500 50067933 64022502 50094526 64029736 50197704 64032054 6/11/08 7/29/08 10/20/08 9/28/08 3/24/09 6/2/09 7/20/09 9/28/09 11/9/09 1/4/10 X

X X

X 2

BP043B BP043C R0203085 R0205679 R0208635 R0209950 R0211299 R0217363 R0219539 R0223149 R0224833 R0226821 R0228766 R0234755 R0236993 R0237255 R0239570 R0241180 R0244457 R0246571 R0248466 R0251555 R0252516 R0255453 R0257215 R0262838 2/18/00 5/24/00 7/12/00 9/6/00 2/02/01 4/13/01 6/26/01 8/23/01 10/24/01 1/11/02 4/26/02 6/28/02 8/27/02 11/4/02 1/14/03 3/10/03 5/13/03 7/9/03 9/2/03 10/30/03 1/27/04 3/20/04 7/16/04 9/7/04 X

X X

X (1)

Diablo Canyon Power Plant Inaccessible Medium Voltage Cables Not Subject to 10 CFR 50.49 Requirements 21 Unit Pull Box RT/Work Order Date Water Found No Water Comments R0264451 R0266340 R0269608 R0271478 R0273110 R0274662 R0278757 R0282500 R0283292 R0285639 R0289865 R0291715 R0295322 R0298946 R0299225 R0401442 R0304519 R0308033 R0310592 R0312775 R0315984 R0318599 R0319908 50067928 64022497 50067929 64022498 50067930 64022499 50067932 64022500 50067933 64022502 50094526 64029736 50197704 64032054 10/25/04 12/17/04 2/10/05 4/5/05 6/7/05 10/21/05 12/15/05 1/12/06 3/24/06 6/2/06 7/27/06 9/26/06 1/18/07 3/22/07 5/18/07 7/12/07 10/29/07 12/26/07 2/27/08 4/21/08 6/11/08 7/29/08 10/20/08 9/28/08 3/24/09 6/2/09 7/20/09 9/28/09 11/9/09 1/4/10 X

X X

X 2

BPZ42 R0272918 64013654 05/08/06 10/28/09 X

X

Diablo Canyon Power Plant Inaccessible Medium Voltage Cables Not Subject to 10 CFR 50.49 Requirements 22 Unit Pull Box RT/Work Order Date Water Found No Water Comments 2

BPZ43 R0272918 64013654 05/08/06 10/28/09 X

X (1) Water detected and pumped. Volume/Depth not reported (2) R0211299 did not identify which boxes required pumping.

(3) BP025 greater than 12" water. Cables not submerged. Not Pumped out.

(4) BP025 greater than 12" water. Cables not submerged. No record of pumping.

Diablo Canyon Power Plant Inaccessible Medium Voltage Cables Not Subject to 10 CFR 50.49 Requirements 1

Table 4 Conduit Inspection Results UNIT 1 Medium Voltage conduits from Intake to Turbine Building ASW 11 Conduits Conduit Length From To AR Outage Dry/Wet Comments K1011 64' ASW11 BPZ42 A0674957 1R14 Dry Inspected the entire conduit from BPZ42 towards the motor K0989 375' BPO44B BPZ42 A0674957 1R14 Dry Inspected 96' from BPZ42 and 145' from BPO44B K0800 350' BPO38B BPO44B A0674957 1R14 Dry Inspected 104' from BPO44B and 297' from BPO38B K0776 600' BPO39B BPO38B A0674957 1R14 Dry Inspected 139' from BPO39B and 298' from BPO38B K0670 440' BPO19 BPO39B A0674957 1R14 Dry Inspected 114' from BPO39B and 89' from BPO19 ASW 12 Conduits Conduit Length From To AR Outage Dry/Wet Comments K1017 68' ASW12 BPZ43 A0674957 1R14 Dry Inspected 65' from BPZ43 towards the motor K0983 375' BPO43C BPZ43 A0674957 1R14 Dry Inspected 100' from BPZ43 and 190' from BPO43C K0808 350' BPO35C BPO43C A0674957 1R14 Dry Inspected 174' from BPO43C and 152' from BPO35C K0784 600' BPO29C BPO35C A0674957 1R14 Dry Inspected 161' from BPO35C and 95' from BPO29C K0702 440' BPO16 BPO29C A0674957 1R14 Wet Inspected 200' from BPO29C and found solid water from 15' to 70' and intermittent water from 100' to 200'. Most of the water was removed 0 to 100 (length of the hose). Minor liquid remains under the cables. Also inspected 210' from BPO16 and found solid water from 45' to 75' and intermittent water from 90' to 200'. Removed the water up to 113' from BPO16. A pocket of water remains in the conduit at about 175' from BPO16 that we could not get the hose to reach.

Diablo Canyon Power Plant Inaccessible Medium Voltage Cables Not Subject to 10 CFR 50.49 Requirements 2

Medium Voltage Conduits from Auxiliary to Turbine Building Bus F Conduit Circuit AR Length From To Outage Dry/Wet Comments K0548 F09H00 A0584492 300' BPG4 BPO7 1R14 dry K0549 F10H00 A0584493 300' BPG4 BPO7 1R14 dry K0553 F12H00 A0584495 300' BPG4 BPO7 1R14 dry Bus G Conduit Circuit Length From To Outage Dry/Wet Comments K0527 G07H00 A0580915 316' BPG5 BPO4 1R15 K0529 G10H00 A0580936 316' BPG5 BPO4 1R15 K0526 G12H00 A0580918 316' BPG5 BPO4 1R15 Bus H Conduit Circuit Length From To Outage Dry/Wet Comments K0503 H08H00 A0584499 350' BPG6 BPO1 1R13 wet K0503 had small sections of the conduit half full of water at distance 200 and 250.

K0502 H09H00 A0584500 350' BPG6 BPO1 1R13 dry K0505 H10H00 A0584505 350' BPG6 BPO1 1R13 wet K0505 had section half full of water at distance 130 K0504 H12H00 A0584509 350' BPG6 BPO1 1R13 wet K0504 had section full of water at distance 226 and 305

Diablo Canyon Power Plant Inaccessible Medium Voltage Cables Not Subject to 10 CFR 50.49 Requirements 3

Table 5. Intake Pull Box Inspections Unit 1 Work Order Pull Box Date Water Found Additional Comments R0272915 BPZ40 11/18/05 N

R0280284 BPZ40 05/04/07 N

Problems noted with concrete spalling and conductor rack degradation. Reference AR # 695170 and 695173.

R0272915 BPZ41 11/18/05 N

R0280284 BPZ41 05/04/07 N

Problems noted with concrete spalling and conductor rack degradation. Reference AR # 695170 and 695173.

R0272915 BPZ42 11/18/05 N

R0280284 BPZ42 05/04/07 N

Problems noted with concrete spalling and conductor rack degradation. Reference AR # 695170 and 695173.

R0272915 BPZ43 11/18/05 N

R0280284 BPZ43 05/04/07 N

Problems noted with concrete spalling and conductor rack degradation. Reference AR # 695170 and 695173.

R0272915 BPZ44 11/18/05 N

R0280284 BPZ44 05/04/07 N

Problems noted with concrete spalling and conductor rack degradation. Reference AR # 695170 and 695173.

Diablo Canyon Power Plant Inaccessible Medium Voltage Cables Not Subject to 10 CFR 50.49 Requirements 4

Unit 2 Work Order Pull Box Date Water Found Additional Comments R0272918 BPZ40 05/08/06 N