ML050830330

Slides: Point Beach Unit 1, Spring 2004 RPV Head Inspection Results Conference Call Tuesday, May 11, 2004 W/Handwritten Notes

ML050830330
Person / Time
Site:	Point Beach
Issue date:	05/11/2004
From:	Nuclear Management Co
To:	Office of Nuclear Reactor Regulation
References
FOIA/PA-2004-0282
Download: ML050830330 (36)

Text

/

Point Beach Nuclear Plant Unit 1-Spring 2004 RPV Head Inspection Results Conference Call Tuesday May 11, 2004

Purpose

• R-l6iew RPV inspection results from the

/PBNP-1 refueling outage (Ul R28)

//

-,Limitation in coverage of Nozzles 32 & 33

- Relaxation of NRC Order EA-03-09 is requested Discuss Repairs being performed on

- 'iNozzle 26 Areva's ID Temperbead (IDTB) repair process

Ž Revised relief requests required for this repair due`to-A52 to A82/1 82 weld overlap I

Committed to Nuclear Excellence -

PBNP-1 General RPV Design Information

• Westinghouse 2-loop design (132" ID)

• Alloy 182 J-groove welds

• Fabricated by B&W

• EDY 15.5 - high susceptibility category of NRC Order EA-03-09 Committed to Nuclear Excellence

PBNP-1 Inspection History & Plans

• Eddy current exam performed in 1994

- No indications (95% coverage)

• Bare-metal visual (BMV) exam performed in Fall 2002 (no indications)

• UT examination performed in Fall 2002 (no indications)

- Greater than 90% coverage

• RPV head will be replaced during U1 R29 (18 months - Fall 2005)

Nq

)

Committed to Nuclear Excellence

CRDM Penetration Configuration

• 49 CRDM Penetrations

• 33 w/ thermal sleeves

• 16 open housings

• 1 vent line NCCe Committed to Nuclear Excellence

CRD Penetration Layout 27rt td a

ISO (Stud 251 0

goo Itsar 13 View Fmm Above Committed to Nuclear Excellence Co f.

U1R28 Inspection Results

• BMV exam essentially complete w/ no indications

• Overall > 95% UT coverage

• Limitations

- All thermal sleeved locations (33) have minor area of lack of OD coverage of 0.4" at bottom of tubes due to probe design

- Nozzles 32 & 33 have inaccessible areas due to weld distortion

• Nozzle 26 Repair

- UT and surface indications Committed to Nuclear Excellence

0 UT Limitations - Tube Bottom at OD

• Due to design of blade type UT probes, a small area owe

)d on the bottom OD of tubes is unexamined

• Generic issue with J"S e Weia the Areva blade tool Unscanned Area Ni~)

Committed to Nuclear Excellence

UT Limitations - Tube Bottom at OD

• Flaw assumed in the unexamined area (L flaw) and grows axially through the scanned area L axial (minimum is 0.41")

_L axial

'rL flaw NM Committed to Nuclear Excellence 7

Co)

UT Limitations - Tube Bottom at OD (cont.)

• Using conservative PBNP crack growth rate data (2 x 10-5 in/yr) derived from MRP-55, this worst-case flaw will take over 2.3 years to reach the J-groove weld

• Relaxation to Order EA-03-09 will be requested Committed to Nuclear Excellence

UT Limitations - Nozzles 32 & 33

• Weld distortion limits blade-probe access

• Sleeves were removed in 2002 for full access (3 man-Rem per sleeve expended)

• No indications seen in 2002 Nu Commiitted to Nuclear Excellence

UT Limitations - Nozzles 32 & 33

• 2004 Results (wlo sleeve removal)

- Nozzle 32 A-IC czeJ

0-milk 11
1

• 3600 of coverage above and ir(

weld zone

• 990 coverage below, weld esa 6 L&

- Nozzle 33

• 300° of coverage above and i weld area

• 570 coverage below1Ield

• Ability to remove and reatt rmal sleeve to support additional inspections is difficult NeC Commtitted to Nutclear Excellence

A Penetration 32 FRAMATOME ANP 10.0 9.50 9.0 8.0 7.5 -

co 545 -

--- -0 4.0

- -il - - - - -

M 2 5

- ---1

- -m 7.0-X-

6.5 6.50

-l-

-- -- i-

-5.5 405-

- - - l1------l-

-f Z

4.0 3.5 2.0 1.5 205 0.0 o

60 120 180 240 300 360 Dep.

Q Z

2 m

z m

Ir
m L

A FRAMATOME ANP Penetation 33 go w

\\

\\-

300 360 0

60 120 180 240 Degree (o5

UT Limitations - Nozzles 32 & 33 (cont.)

• Circumferential flaw above J-groove weld assessed

- Initial flaw size of 60° (i.e., 3 Nozzle 33 00° of UT coverage)

- Using WCAP-14000 and MRP-55 crack grovk rate data, it would take an undetected flaw 3 years to grow to a allowable lengd (3000)

NM)

Committed to Nuclear Excellence f

UT Limitations - Nozzles 32 & 33 (cont.)

• ~rmal sleeve removal is very difficult for t

se nozzles due to X removal and welding process performed in 2002

• Relaxation from EA-03-09 will be sougi for (9 limitation in coverage

- Structural Integrity Associates (SIA - Riccardella) analysis supports minor limitations in coverage

- Pis work was presented to NRR in February 2004 in preparation for(k outage Committed to Nuclear Excellence

UT Limitations - Nozzles 32 & 33 (cont.)

0 6SIAanalysis assumed only§ob%

coverage during U 1 R28 (actual



95%)

coverage in SIA analysis assumed only 50%

_outer ring nozzles 26 - 33 0

results indicate an insignificant difference e probability of leakage compared to t

we ot Tull coverage

- Differences do not warrant additional man-Rem required for ermal sleeve removal Committed to Nuclear Excellence -

PBNP Results Probability of Leakage (per vessel year) 2.OOE-01 1.80E-01 1.60E-01 Ka,-

VI 0

0 0

a.

1.40E-01 1.20E-01 1.OOE-01 8.OOE-02 6.OOE-02 4.OOE-02 2.OOE-02 O.OOE+00 0

5 10 15 20 EFPYS 25 NM Excellenc e C(OG Committed to Nuclear

Nozzle 26 Indications JRC J1W 7Or i

• Large UT signal detected weld roo (dow I location

_ 180°)

Signal attributed to a fabrication weld repair performed during construction NMC)

Committed to Nuclear Excellencel cD7

Nozzle 26 Indications (Cont.)

a!

Jo

~LI ii, AC I

'V I j N:

I' S~ 4.

£%

AL 9'"

I I

/7

/

• weld repair performed at this

, I location

• 1969 inspection report Weld Repair Root Pass" I

I I

'1 I - I I -7 4-f.

_7P PI if V if U,j4 1IM/

lJ zM,' tr CNo t Committed to Nuclear Excellence

Nozzle 26 Indications (cont.)

Several PTs revealed J-groove surface indications at the 90° and 2700 locations (see following diagrams)

Based on grinding and subsequent PTs depth is

> 3/16 inch

/Conservative repair of nozzle being performed due to high dose involved with flaw excavation NMC Committed to Nuclear Excellence t

C0t9j

NozzI e 26 Indications (Cont.)

I WHII"-

4f.tJ An.41

/41

• PT and UT signals JA IN superimposed

• Correlation between UT and PT signals

• Additional repair stresses (illustrative diagram)

I DWNHIW Committed to Nuclear Excellence

Nozzle 26 Repair

• Areva IDTB repair is in progress

• Complicated process due to smaller Westinghouse 2-loop RPV design

• Simplified repair process outline follows Nur l

Committed to Nucolear Excellence

"~

Step 1 - Thermal Sleeve Removal SLEEVE CUT UNE

• Sever existing thermal sleeve STEP 1 THERMAL SLEEVE CUTTING No Committed to Nuclear Excellence

Step 2-NDE & Roll Expansion

• Perform baseline rotating UT

• Using UT, take as-built measurements

• Roll expand nozzle STEP 2 ROLL EXPANSION N,

)

Committed to Nuclear Excellence

Step 3 Machining of Nozzle

• Locate cut-line M*Machine the lower nozzle and form weld prep

• Etch the original J-groove weld to locate fusion line

• Size weld overlap

• PT and UT the original J-groove weld in the area of the overlap STEP 3 NOZZLE REMOVAL AND WELD PREP MACHINING Committed to Nuclear Excellence

Step 4-Welding

• Perform IDTB Weld

• 48 hour5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> Hold STEP 4 WELDING Nec Committed to Nuclear Excellenc

Step 5 -Machining of Weld & NDE

• Machining of weld surface suitable for NDE during 48 hour5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />

• Perform UT and PT of weld after the 48 hour5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> hold STEP 5 GRINDING, MACHINING, AND NDE N)

Committed to Nuclear Excellence

Step 6-Chamfer Grinding

• Grind chamfer on existing structural weld Committed to Nuclear Excellence STEP 6 ORIGINAL WELD GRINDING

Step 7

-Thermal Sleeve Installation A

• Install and weld replacement thermal sleeve "I,

L STEP 7 THERMAL SLEEVE REATTACHMENT Committed to Nuclear Excellence

Nozzle 26 Weld Overlap Condition

• With small diameter Weld ligament (132") heads, the repair A52 weld will come into contact with the existing A182 J-groove weld

• Unique design challenge for the Westinghouse 2-loop GRINDING/MACHINING plants AND NDE Committed to Nuclear Excellence

Nozzle 26 Weld Overlap Condition (cont.)

• NMC met with NRR on October 6th 2003 &

February 1 9th 2004 to discuss this issue NC i t Committed to Nuclear Excellence2

Nozzle 26 Weld Overlap Condition (cont.)

• Crack growth rates (CGRs) in the Alloy 52 material are very low

• The analysis therefore conservatively assumed Alloy 600 CGRs (MRP-55)

• Analysis demonstrated that a worst-case flaw in the A82/1 82 would take in excess of 1.5 EFPY to go through the remaining Alloy 52 weld (0.26" weld ligament assumed)

• Separation via grinding was considered but determined to not be appropriate due to very high dose NM Committed to Nuclear Excellence

Nozzle 26 Weld Overlap Condition (cont.)

• Actual weld ligament will be ~ 0.44 inches &

the worst-case flaw would take over 2 years to pass through the A52 fusion zone

• Revised IDTB relief request will be processed using actual dimensions Nee Committed to Nuclear Excellence a

Summary

• An NRC Order EA-03-09 relaxation request will be immediately submitted using actual coverage data

• A revised IDTB relief request will be submitted on Thursday May 13th using actual weld overlap data NM Committed to Nuclear Excellence

Summary / Questions Nc Committed to Nuclear Excellence