ML20083N658

Informal Technical Communication Re 820721 Meeting in Livingston,Nj Concerning Schedule for Qualification Program of Tube Repair & Results of Preliminary Tests.Ornl 820817 Memo Re 820808-09 Meeting & Summary of 820915 Meeting Encl

ML20083N658
Person / Time
Site:	Three Mile Island
Issue date:	08/04/1982
From:	Leonard L, Shook T FRANKLIN INSTITUTE
To:	Jacobs R, Rajan J NRC
Shared Package
ML20083L719	List: ML20083N658 ML20083N666
References
FOIA-82-552 NUDOCS 8302020436
Download: ML20083N658 (9)

Text

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INFO.WAL TECHNICAL COMMUNICATION # *

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To: 7 N l2A FAlJ f/CK 3A<08.5 From: FED SND0k./h/ Pry /sppyg U.S. Nuclear Regulatory Commission FranklinResearc[hCenter Washington, D. C. 20555 Philadelphia, PA 19103

('IO BE OPENED BY ADDRESSEE ONLY)

Reference:

NRC Contract NRC-03-81-130 FRC Project C5506 M / u n gff7- /0 NRC TAC No. FRC Generic Topic 'TM / -/

Plant r7-R / - / FRC Task (s) 3 //, 3/2. . .?/3 [4 gC]

Title:

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Copy of message form only: . NOTE 'IO SENDER: Include

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~~~ pertinent to program management..

S. S. Sajwa NRC Per formance kbnitor W f] E R T 8(2Akur2 NRC Lead Project Manager /' C//hA B Aic C/2ACI'fAJ FRC Distribution: EPC, SP, -T'5 , L L; E,_C Q., - , ,

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8302020436 821130

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Revised 4/10/82 DOROSHOS2-552 PDR M ~~.-"

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TRIP REPORT: PROJECT C5506, Assignment 10.

PLACE VISITED: Foster Wheeler, Livingston, NJ DATE: July 21,1982 THOSE PRESENT: Representatives from:

NRC FRC GPU N

B&W Present from FRC:

L. Leonard .

C. T. Davey

.. V. Luk ,

T. A. Shook

, PCIPOSE OF MEETING: To present schedule for qualification program of tube repair, and result of preliminary tests performed.

Interface with technical personnel on the status of analytical work.

1. This meeting revealed newer, more up to date plans than previous meetings.

.It allowed more direct interactions among technical personnel present. -

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, 2. , Progress was announced on the Ordnance Cord-booster concept for candle Initiation. This initiation process should result in less explosive reaction outside the expansion space, and thereby reduce contamination and potential damage as a result of the more brisant primacord initiation

' process that the Ordnance Cord replaced. Further studies are planned to 6onfirm that Ordnance Cord is appropriate. ,

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Dr. Pai (Foster Wheeler) expresses belief that the booster will have no more explosive ef fect than an equivalent length of primacord. '

3.' 'The schedule for delivery of the six single-tube and two ten-tube test spdcicens was discus'ed.

s Delivery was to be in late September.to FRC, however, more recent information indicates that FRC should have all fixtures and hardware by mid-August.

s' Foster-Wheeler has partially completed their apparatus for cyclic testing

, of the ' ten-tube mock-ups. The test parameters are slightly different

• than' FRC's but at this time it appears that results should be comparable.

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4. The~ pull-out tests showed that the load required to pull out an expanded tube (af ter the two step process) is essentially independent of the extended length for lengths above about 5 inches. Accordingly, Foster Wheeler is qualifying a six inch length even though the minimum expansion at this- time will be 17 in. For tubes which leak in the tube sheet after the 17" expansion, a follow-up 23" expansion can he utilized to seal a

. new 6" qualified' length below the original expansion. Peripheral tubes , ,,,

cay cause problems; the canale cannot be injected easily. . -.

5. There were some serious concerns if the expansion is performed too'ciose to the juncture of the tube and the tube sheet, placing the transition near the inside surface of the tube sheet. A do'uble ended rupture was feared that would.potentially cause serious leaks.

Particular concern was expressed in the event of a steam line break during which time a temperature difference would exist in which the tube would be at a lower temperature than the tube sheet. The ac.cocpanying

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tube shrinkage would result in a tensile load on the tube.

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This situation will be investigated by B&W. [

6. X-ray diffraction residual stress measurements will be made at Penn State University to evaluate the relative magnitude of stresses induced by tube rolling and explosive expansion both in fully expanded areas and in the transition to the unexpanded region. These tests.will take about 2 to 2h months to complete, and, thus, all results will not be available until the

, beginning of October. This should present no problem with regard to the

.- implementation of repairs since it is highly likely that the expansion

,,,,, residual stresses will be less than those from rolling. The tests are to

,,fl demonstrate how much more uniform and less severe the stresses are resulting

~~ frqm explosive expansion than-from rolling.

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lC-# Candles will be supplied to FRC by Foster Wheeler for any experiments we

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,w ish to run. It was confirmed that FRC is fully licensed to store explosives (Federal, State and City licenses).

8.. [. Multiple expansions are planned at Mount Vernon, Indiana on 5 August,1982.

6'rJ'This is a B&W " graveyard" for old steam generators.- FRC observers will

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9. Materials presented during this meeting will be mailed to FRC by GPUN af ter appropriate approvals. As of this writing these materials have not been

. received.

10. A meeting was held between Vincent Luk of FRC and Jim Moore of GPU at GFU.

The purpose of the meeting was to discuss the Licensee's stress evaluation program. At the meeting, FRC reviewed a draft GPU Stress Report, TDR No. 346,

. , _"TM1-1 OTSG As-Built Stress Analyses." The report focuses-on the review and

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' evaluation of the performance of the as-built steam generator, and it does not address the ef fects of the kinetic expansion process ca the' performance of the Gni t. The report will probably be released to public domain by 7/23/82. FRC

--may get a copy of the report before the end of July 1982. At the meeting, the scope of stress analyses which FRC would like to be covered by licensee das discussed in detail. According to Jim Moore, most items covered in FRC's scope will be included in licensee's test qualification program and the re-

+ maining few ite=s will be evaluated analytically by either.GPU or B&W. All

.t.he results from qualification and stress evaluation programs will be reviewed by FRC when they become available.

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11. A. request was cade to Mary Jane Graham for the following documents:

a. Mechanical drawings of tube bundle and tubesheet assembly together with tube  !

support system. -

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b.- Proprietary _ Topical Report, B&W-10002, e-

"Once Through Steam Generator Research and Development Report." ,

c. B&W-10146, " Determination of Minimum Required Tube Wall Thickness for 177 -

F/A OTSG's, " Babcock & Wilcox Report."

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INTRA LABORATORY CORRESPONDENCE OAK RIDGE NATICNAL L ABOR ATORY

, N August 17, 1982 To: R. W. McClung hos: C. V. Dodd d . V. O M

Subject:

Travel to Harrisburg, Pennsylvania, August 8-9, 1982 On Monday, August 8, I met with General Public Utilities (GPU) and NRC personnel to discuss the eddy-current inspection of the Three-Mile Island Unit 1 steam generators. A partial list of attendees is attached.

Nick Kazanas of GPU gave a presentation of the development and

, qualification program for the eddy-current inspection of the steam generators. A set of inside diameter calibration standards with ,

,gircumferential notch lengths of 0.060, 0.100, and 0.187'in., notch depths

,of,[20, 40, 60, and 80%, and widths of typically 0.004 to 0.005 in. were

.- coris true,ted . In addition, an axial notch standard with 0.060 in. long notches was constructed.

These standards were used to test circumferential differentia 1' probes of 0.516 and 0.540 in., and an eight-coil array with 0.187 in, outside .

diameter pancake coils. Various gain and other conditions were run. The besti.. combination for the differential coil system was the 0.540~ in.

ososid~e diameter probe with a permanent magnet saturating core and d gain

. setting of 60. The permanent magnet should not have increased'the signal an'y but only reduce the noise a small amount. I examined a probe and its field did not seem strong enough to saturate any ~ ferromagnetism associated with Inconel (about 0.3 T is usually needed). However, it di'd seem to be more ' carefully made than the regular 0.540 in. probe. An addit'ional mix .

of the 200 and 400 kHz mixed signal with an 800 kHz signal reduc'ed the noise:due to probe chatter and pilgering.

The 8XI absolute probe showed more signal to the small defects at a gain of _5% . but a fairly large lif t-of f signal was also present. The 8X1 probe arraf'.is being revised to increase the probe body from 0.520 to 0.540. in, which,should reduce the lif,t-of f , problem.

A corr lation of the ' defects seen by the pancake coils with the defects seen 0,ith the 0.340 in. outside diameter differential probe showed that of 3233 defects detected by, the pancake coil, 3216 were also detected by the differential probe. This number was improved to 3229 by using the mix to

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reduce .the inside diameter noise. This shows an excellent match and also . .

showed.that the 0.540 in. differential probe, operated under these-- - -

conditions, can reliably detect the same type of circumferential crack.

In order to directly apply the results obtained from the electrodischarge

• machined standards, an " effective axial crack width" for these

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intergranular stress-corrosion cracks must be-determined.

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R. W. licClung Page Two August 17, 1982

.On Monday afternoon, John Janiszewski of GPU gave a presentation of the results of the metallography of the cracks. Some cracks appeared to have regions of bulk intergranular attack associated with them, and some appeared to be very narrow with very little branching and axial component.

However, the crack would only need a few branches to ef fectively disrupt the fica of eddy currents.

John Janiszewski will generate an " effective axial component" by reviewing the results of the previous metallography and furnish it to us. This number will show how applicable the calibration results from electrodischarge machined notches is for the circumferential cracks, and furnish an independent verification of the ability to detect the defects with a different probe. The results of a dimensional analysis experiment using large scale models at ORNL will be used to correct the sensitivity at ona length to the sensitivity at another. It was stated that the .

region ^near the crack was depleted in chrome, but no estimate was made of "thF bulk electrical and magnetic properties of the region. A total of 19:ft of " good" tubing has been examined by metallography, with an additio'nal 6 ft to be examined. No defects were detected by this test that were missed by the eddy-current test. Some of the defects detected by the eddy currents were not found by the metallographic examination,

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p'roliably due to the way the samples were cut. Some of the eddy current sigKals turned out to be due to manufacturing, handling, and assembly art %f acts, and would not be de'trimental to the service of the tube.

w>7 On Tuesday I visited the data reduction site at the Host Inn near the

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plant. I reviewed the results of the scan on tube A71-126. This tube was pullied and a section sent to ORNL for examination. A through-wall defect wa's detected using a high-frequency (5 MHz) scan with a small'(0.020 in.

mdant racTius) probe from the outside. The defect was then etched and showed a 0.005 to 0.010-in.-wide affected region on the outer surface. It is not known if this entire region appears as a low conductivity reg' ion of not. The defect was record,ed as ,80% through-wall by ConAm, and a blind remeasurement of the defect from tape showed 84%. The magnitude of the

. signal was 1/2 V at a gain of 34, and an 0.51'O in, outside diameter differential probe was used.

I also, looked at runs using' the 0.540 in. outside diameter diffe'rential probe, with a gain of' 60. The practical noise -level to get a reasonable measurement of the defect depth appears to be around 0.5 V, although in many._' cases smaller defects can be measured. Based on the 0.005 in, wide standards, this falls in the range of a 0.060 in. long defect, 40%

+ through-wall. Depth measurements on smaller defects will prohably'be very inaccurate. , ,

A 100% inspection of the full length of all the tubes is being performed

~using. the 0.540 in. probe with a gain of 60. The number of indications is about three times as many as were observed with the 0.510 in. dif ferential probe. Tube B10-48 showed 16 inside diameter defects', all about i V in amplitude, between 30 and 60% of the wall. The lowest defect was near the

~ third support plate. The high sensitivity of this new inspection is also , _,,

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,,R. W. McClung Page Three August 17, 1982 picking up a number of outside diameter signals from the manufacturing process, which are not detrimental to the service and can be ignored. The' tubes that exhibit the inside diameter signals should be rescanned with the 8X1 pancake coil array, and the tubes with defects greater than the plugging limit plugged. The tubes with defects below the plugging limit i can be reexamined at later intervals to monitor growth of this type of defect.

There appears to be a drif t and a quality assurance problem with the probes. This problem doesn't af fect the accuracy of the test, but results in frequent probe changes. The inclusion of several of these types of defects in an in-line standard (for future tests) should be considered.

The instrument gain in the field is set to give a repeatable voltage amplitude from a drilled hole flaw, rather than an absolute number.

The pancake coil array is operated at a single frequency and much more

. -susceptible to different types of noise than the differential probe. This

. . arj[ay also requires much more equipment than the differential probe.

2etsc is working on a more compact system, but no estimate of the

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, _ availability of this instrumentation was given.

. The.results that I saw on Ibnday and Tuesday answered all the previous quegtions that Emmett Murphy had submitted in his letter of April 12, 1984,except the one on safety evaluation. Some attempt should be made to' detsymine how large a defect would have to be before it would present a, D$fety problem. I feel that the defects that can now be reliably detected

,are ' much smaller than those that would present a hazard, but .have no inf ormation to back this up. ,

The . study, done by. the utility, their contractors, and the EPR1 NDE Center to determine their sencitivity limits, was outstanding. .

CVD:jlb - -

'ce: ,R. Barley, GPU J. H. DeVan L.~ Frank, NRC/ . .

J. C. Griess

" y. J. Homan N. Kazanas, GPU

-A. L. Lotts .

C. McCracken, NRC *

• J. liuscara, NRC

- -P. Patriarca G. M. Slaughter J. H. Smith .

P. Wu, NRC ~ ~*

- C. V, Dodd/ File

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JEETING REPORT

, Place: Bethesda, MD Date: September 15, 1982 Present: Representatives of NRC, GPUN, FW AND B&W FRC Representatives - C. Davey L. Leonard '

V. Luk T.. Shook The purpose of this meeting was for the licensee, GPUN, to make its final

.. ' presentation of the TMI-1 OTSG repair process description and qualification.

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. Mis cEllaneous

.A v,1d,co tapc of parts of the Mt. Vernon demonstration was presented.

. It,was stated that the kinetic expansion of the THI tubec is to begin earlyhinOctober.

A th hd party review is being conducted to provide evaluation of the, adequacy oS4th'e steam generator repair program as it relates to safe operation of the -

plan t .'

Repair Criteria An acdeptable leakage rate from primary to secondary has been established. ..

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The value is 3.2 x 10-6 lbs/hr per tube. . . .

The pull-out strength must be greater than the maximum anticipated accident load condition (3140# for a MSLB).

Thermal and hydraulic performance of plant and structural adequacy shall be within_ acceptance criteria for normal and accident conditions. Evaluation has not yet-been completed. ,

Criter{a for plugging or expanding tubes was presented. It is estimated that approximately 750 tubes will have to be plugged, initially.

Sequential steps were presented for the repair process. Details of the clean-up process af ter the expansion have not yet been made available, houever the -

decision to pre-coat the tubes should accelerate this process.

Tests -

GPUN will p'ublish a report by October 1,1982, documenting all test data taken to date. -

All testing will be completed by November 10th.

A .G' Penn State is approximately 25% into its test program of single and multi-tube l test specimens. -

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Meeting Report 9/15/82 5506-001 (10000)

GPUN reported the results of pull-out tests on the Mt. Vernon generator.

Three tubes were subjected to loads of 3600 lbs, and there was no move-ment of the tubes under these loads. This data has not yet been documented.

GPUN will perform high temperature pull-out tests on one of their test blocks.

Results will be verbally relayed to FRC.

Discussion of FRC's Request for Additional Information A formal RAI was issued on August 27, 1982 to the NRC by the FRC. The various items of this request were reviewed, and their status determined.

, It was agreed to hold a meeting at Lynchburg to discuss the unresolved items.

.. -This mee. ting was held on September 20, 1982. _

_ (Aji}'t of items was drawn by FRC (8 in number), and presented to GPUN, W, and' MW,;for the meeting, at their request.

~~At th'e meeting, the status of each item was determined,

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i.e., available, not available at present, will never be available.

A trip report has been released giving details of this meeting.  !

FEh,1$ proceeding with its preliminary TER based on documentation received as

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. of this date, and on the results of its own independent test program. to date.

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