ML063420628

E-MAIL: (PA) Fwd: Slides

ML063420628
Person / Time
Site:	Oyster Creek
Issue date:	10/24/2006
From:	O'Hara T NRC/RGN-I/DRS/PSB2
To:	Kaufman P NRC Region 1
References
%dam200701, TAC 8261
Download: ML063420628 (19)

Text

T0ithyoqH ara - Fwd: Slides .page 1 From: Timothy O'Hara To: Kaufman, Paul Date: 10/24/2006 8:13:36 AM

Subject:

Fwd: Slides FYI, Tim O'Hara

Timothy O'Hara- SSlides Page 1 From: <john.hufnagel @exeloncorp.com>

To: <tlol @nrc.gov>

Date: 10/23/2006 4:15:34 PM

Subject:

Slides

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Mail Envelope Properties (453E0370.2A5 : 23 : 27097)

Subject:

Fwd: Slides Creation Date 10/24/2006 8:13:36 AM From: Timothy O'Hara Created By: TLO I @nrc.gov Recipients Action Date & Time nrc.gov kpl po.KPDO Delivered 10/24/2006 8:13:36 AM PDK (Paul Kaufman) Opened 10/24/2006 8:15:21 AM Post Office Delivered Route kpl-po.KPDO 10/24/2006 8:13:36 AM nrc.gov Files Size Date & Time MESSAGE 325 10/24/2006 8:13:36 AM Mail Options Auto Delete: No Expiration Date: None Notify Recipients: Yes Priority: Standard ReplyRequested: No Return Notification: None Concealed

Subject:

No Security: Standard To Be Delivered: Immediate Status Tracking: All Information

Tm0othy OHara- Comm Doc - Drywell Inspections[10-23-06 alexippt Page 11 Oyster Creek IR21 Outage Communication Package Related to Drywell Shell Inspections October 23, 2006

<date> PRELIMINARY I

JTimoth ý'Hara Comm Doc'- Drywell ,IspIection-s1-23-06 aex.ppt pt Page2 1R21 Drywell Inspections

• Reactor Cavity Trough Drain Line

" Sand Bed Region Poly Bottles

• Sand Bed Drain Lines

" Epoxy Coating on External Surface of Drywell Sandbed in all 10 Bays

• Internal Drywell Shell in Sand Bed Region Above Floor Elevation

• Internal Drywell Shell in Upper Regions

• Seal at the junction between drywell shell and concrete floor in Sand Bed Region

" External Drywell Shell in Sand Bed Region

• Plate Thickness Transitions at Two Elevations

" Internal Drywell Shell in Trenches (Bays 5 and 17)

<date> PRELIMINARY 2

Timothy O'Ha-a - Comm Doc - Drywell Inspections 10-23-06 alex.ppt Page3 Inspection Status (To Date)

• The reactor cavity trough drain line is not clogged and is successfully removing a small amount of water entering the trough. Daily water leakage monitoring continues (as planned, strippable coating was applied to reactor cavity before flood-up).

• There has been no water observed in the Sand Bed Regions and no water coming down through the air gap.

" There has been no water leakage from the Sand Bed Regions confirmed by the absence of water in the poly bottles. Daily monitoring of the poly bottles continues.

• Two of the five Sand Bed drain lines were found to have some blockage and debris. These will be cleaned prior to restart.

" The visual inspection of the epoxy coating on the external shell surface in the Sand Bed regions has been completed.

• The seal at the junction of the drywell shell and the concrete floor in the Sand Bed region has been inspected.

<date> PRELIMINARY 3

Timothy OHara - Comm.... .Page4]

Inspection Status (To Date)

• The Ultrasonic Inspections of the Interior Surface of the Drywell in the Sand Bed regions have been completed.

• The Ultrasonic Inspections of the Interior Surface of the Drywell in the Upper regions are in progress.

• The Ultrasonic Inspections of the Exterior Surface of the Drywell in the Sand Bed regions are completed.

• The Ultrasonic Inspections of the plate thickness transitions at two locations are in progress.

• The Ultrasonic Inspections of the Interior Surface of the Drywell in the Trenches in Bays 5 & 17 have been completed.

<date> PRELIMINARY 4

Timothy O'Hara - Co-m-m Doc - Dryw!e Inspecttions 10-23-06a!expp . . ... . Page 5'.

Issues Identified

• Standing water was identified in the trench inside the Drywell at the Drywell floor level in Bay 5 when the foam fill was removed for planned inspections.

• Dampness was identified in the other trench in Bay 17; however, no standing water was present.

• The Drywell drain trough may be a contributor to water leakage into the trench in Bay 5.

<date> PRELIMINARY 5

'Hara - Comm Doc - Drywell lpspeýfior?ý alex.ppý ýge Page I Timothy QHara - Comm Doc Dryweli Inspections 10-23-06 alex.ppt Water in Bay 5 Trench Description of Findings and Actions to Resolve this Issue

<date> PRELIMINARY 6

Timiotýhy O'Hara --Comm Doc- Drywell Inspections- 10-23-06 alex.ppt Page 71I Issue Description

" When performing planned Non Destructive Examinations of the Drywell Shell from inside the Drywell, water was found in a trench area below the floor elevation.

" A similar condition was identified in the mid 1990s and documented in the corrective action process.

" The source of this water needs to be understood and addressed, and any impact on the drywell shell or concrete evaluated and addressed.

<date> PRELIMINARY 7

TimothyOHara - Comm Do: P_-rywel! !nspections 10-23-06 alex.ppt Page 8 Drywell Design and Layout

" The Drywell floor drain sump is located within the under-vessel area room

" A concrete trough encircles the under-vessel area to channel any leakage in the drywell to the drywell sump

<date> PRELIMINARY 8

I LTimothy O'Hara- Comm Doc- Drywell Inspections 10-23-06 alex.ppt Page 91 Sketch Showing Lower Drywell - Sandbed, Trench and Sump 4

1:Tim-oth.y- O'Hara Comm Doc - Drywell Inspections 10-23-06 alex.ppt Pag~e 10!1 Page lOfj ITimothy OHara - Comm Doc - Dryweli Inspections 10-23-06 alex.ppt Trench Detail Sketch LIGHT OENSITY SILICONE I Nc.

DRYTWELL VARIES CROSS-SECTION AREA OF TRENCHES IN BAYS 5 & 17

.1. 1 1

[ T66thy O'Hara - Comm'Doc -'Drywell Inspections 10-23-06 alex.ppt Page 111 Page 11 FTimothy OHara Comm Doc Drywell Inspections 10-23-06 alex.ppt Plan View of Trough and Trenches

<date> 11 KEY PLAN

T!mothy OHara -CommDoc , Drywell Inspections 10-23-06 a!eýx.ppý.t Page 12I Top View - Drywell Floor Sketch 12

Timothy O'Hara -Comm Doc,- Drweinpec~tions 10-23-06 alex.ppt P.age 131 As Found Condition 0 Surface of drywell shell visible from trenches in Bays 5 and 17 exhibited a surface layer of iron oxide

• Approximately 5" of water found in bottom of trench in Bay # 5, and trench in Bay 17 had only dampness

• Connection between under-vessel area trough and floor drain sump potentially allowing water leakage

" Trough located in the under-vessel area is not lined, potentially allowing water passage into the concrete slab

<date> PRELIMINARY 13

[ Tiriio-thy O'Hara - Comm Doc - Drýý611 Inspections 10-23-06 alex.ppt Page 14 t y-OT ara Tim oth... ** ... *~*-T*

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Investigative/Corrective Actions Completed

" Visual inspections and pictures taken of sump, trough and trench areas

" Visual and Ultrasonic examinations of drywell shell in trench areas (as originally planned)

" Chemical Analysis of water samples from trench, sump and other areas

" Correlation and evaluation of water levels in sump, trough and trench areas

<date> PRELIMINARY 14

ITimth;y OHara' Co6mm Dc-rwI npcin 02-6ae~p _

Actions Planned/Pending

• Visual Examination (VT-1) of floor drain sump liner to look for evidence of a leak path

• Tracer test aimed at determining whether under-vessel trough is in communication with trench in Bay 5

• Development of contingency repair to trough to address likely water source into trench

" Complete non destructive examination and analysis of Drywell shell in trench areas

• Perform evaluation of the impact of water that may exist beneath concrete surface on drywell shell

" Development of contingency repair to caulk intersection of Drywell Shell and concrete slab curb

<date> PRELIMINARY 15

Tim*othy o;Hara -Comm Doc- D,rel1 Inspections 10-23-06 aex.ppt "Page 16 Current Conclusions Preliminary Inspection Results indicate that the Drywell Shell

- Retains its structural integrity

- Provides margin to design safety function

- Supports plant operation for the period of extended operation

<date> PRELIMINARY 16