Text

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)
	v • d • e

/

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)

// -,Limitationin coverage of Nozzles 32 & 33

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

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

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

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 27rttd 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 J"S e Weia

Generic issue with 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")

_Laxial

'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) czeJ

- Nozzle 32 A- IC 0- milk 111 esa 6 L

3600 of coverage above and ir( weld zone

990 coverage below, weld

- 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 NutclearExcellence

A FRAMATOME ANP Penetration 32 10.0 --- -

9.50 9.0 - -. - ..

7.0- --

co8.0 545 . -------------------

- - - - - X-- - ------ ----- --------

- -- - - - --------- -0 - - - -_

4.0 7.5 --

6.5 - - -il- - - - - -. 0-

-5.5 M 2 5- ---1 -- - - - -m-.------

4.0 6.50 -l-- - - -- - - i- -.

2.0 405- - - - l1------l-

-f 1.5 205 0.0 Zo . 60 120 180 240 300 360 Dep.

3.5 Q

Z 2

m z

m I

r m

L

A FRAMATOME ANP Penetation 33

\ \- .... ....-

go w

0 60 120 180 240 300 360 Degree (o5

UT Limitations - Nozzles 32 & 33 (cont.)

Circumferential flaw above Nozzle 33 J-groove weld assessed

- Initial flaw size of 60° (i.e., 300° 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 NuclearExcellence 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 NuclearExcellence

UT Limitations - Nozzles 32 & 33 (cont.)

0 6SIA analysis assumed only§ob%

coverage during U1R28 (actual 95%)

SIA analysis assumed only 50% coverage in

_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 Ka,-

1.60E-01 VI 1.40E-01 0

1.20E-01 0

1.OOE-01 0

8.OOE-02 a.

6.OOE-02 4.OOE-02 2.OOE-02 O.OOE+00 0 5 10 15 20 25 EFPYS NM Committed to Nuclear Excellenc e C(OG

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 NuclearExcellencel cD7

Nozzle 26 Indications (Cont.)

I a!

/7

weld repair Jo

~LI performed ii, I/

AC at this

'V I j N: I' location I

1969 S~ 4. ,I inspection 9'"

Weld Repair Root Pass" report AL

£%

I I I

'1 I -I I -7 4- f. _7PV Uif PI if ,j4 1IM/ lJ zM,'tr CNot Committed to NuclearExcellence

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"-

PT and UT 4f.tJ An.41 signals

/41 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 Nurl 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 NuclearExcellence

Step 4- Welding

Perform IDTB Weld

48 hour5.555556e-4 days 0.0133 hours 7.936508e-5 weeks 1.8264e-5 months 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 0.0133 hours 7.936508e-5 weeks 1.8264e-5 months

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

Committed to Nuclear Excellence

Step 6- Chamfer Grinding

Grind chamfer on existing structural weld STEP 6 ORIGINAL WELD GRINDING Committed to NuclearExcellence

Step 7 -Thermal Sleeve Installation A

Install and weld replacement thermal sleeve "I,

L STEP 7 THERMAL SLEEVE REATTACHMENT Committed to NuclearExcellence

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 AND NDE plants Committed to NuclearExcellence

Nozzle 26 Weld Overlap Condition (cont.)

NMC met with NRR on October 6th 2003 &

February 19th 2004 to discuss this issue NCi 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 NuclearExcellence

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 NuclearExcellence 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 :

ML050830330

Text

Navigation menu

Search