ML20092N722
| ML20092N722 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 06/29/1984 |
| From: | Croneberger D, Giacobbe F GENERAL PUBLIC UTILITIES CORP. |
| To: | |
| Shared Package | |
| ML20092N717 | List: |
| References | |
| 83-491-04-OLA, 83-491-4-OLA, OLA, NUDOCS 8407030478 | |
| Download: ML20092N722 (14) | |
Text
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l RELAIED CC*~n=a?ONDENcg
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-.nu C0cic[R[5 UNITED, STATES OF AMERICA US.5 NUCLEAR REGULATORY COMMISSION
'Before-the Atomic Safety and Licens nd o'akd110 :15 bN
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'In'the Matter _of
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-S i METROPOLITAN EDISON COMPANY, ET AL.)
Docket No. 50-289-OLA
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ASLBP 83-491-04-OLA
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~(Three= Mile Island Nuclear
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(Steam Generator Repair)
Station, Unit-No. 1)
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uLICENSEE'S' TESTIMONY OF DON K. CRONEBERGER AND
- F. SCOTT GIACOBBE ON ISSUE 1.d (CONTENTION ~1.a)
To Mr. Croneberger:
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-Pleasestateyodrnameandaddressanddescribeyour involvement with the TMI-l steam generator tube repair program.
A2.
My name is Don K. Croneberger.
I am employed by GPU Nuclear Corporation,- 100 Interpace Parkway, Parsippany, New Jersey.07054.
As the director of Engineering and Design, I
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_provided technical management oversight of the failure analysis and repair activities,'with special emphasis on. evaluation of the steam generator's mechanical design and the impact of the
. repair on-the response of the components.
My department also provided engineering support in the areas of Materials Engi-neering/ Failure Analysis, Chemical Engineering and Chemistry, Mechanical Engineering and Engineering Mechanics.
A statement of my professional qualifications is attached.
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Q_'-.....,
t To Mr. Giacobbe:
Q2.
Please state your name and address, and describe your
~ involvement with the TMI-1 steam generator tube repair program.
A2.
My name is F.
Scott Giacobbe.
I am employed by GPU Nuclear Corporation, P.O.
Box 1018, Reading, Pennsylvania 19603.
As Manager of Materials Engineering / Failure Analysis, I have been involved in the planning and management of the fail-ure analysis activities, corrosion testing programs, materials evaluation and tube sampling and removal programs associated with the steam generator tube repair program.
A statement of my professional qualifications lo attached.
To all witnesses:
Q3.
What is the purpose of your testimony?
A3.
The purpose of this testimony is to addresc Issue 1.d of Contention 1.a as enumerated at page 23 of the Board's Memo-randum and Order (Rulings on Motions for Summary Disposition, dated June 1, 1984), in which the Licensing Board' stated:
1.
The rationale underlying certain proposed license conditions should be addressed, with attention to:
d.
Adequacy of simulation of operating conditions by long-term corrosion tests.
Q4.
What was the purpose of the long term corrosion test program?
A4.
The purpose of the long term corrosion test program,
-the operations phase of which has now been completed, is to _... _
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4 EverifyLthat sulfur-induced intergranular stress-assisted Jeracking (IGSAC) will not reinitiate or propagate in'the TMI-1 OTSGs'under actual operating conditions. -The tests were de-signed:tol confirm:that the metallurgical, environmental, geo-metric and surface conditions which exist after the repair of
~
the1 tubes are not detrimental to tube integrity.
From the test
. program it:will be possible to conclude whether or not the pro-posed chemistry limits are acceptable, whether the peroxide (cleaning-itself was-beneficial ~~or. damaging, and, more impor-
^
'tantly, whether'the changes in electrochemical potential during operations will cause reinitiation of' corrosion.
The long term. corrosion tests are accordingly related to Lthe kinetic expansion: repair process, but only insofar as they
- verify that the repair did.not render the OTSGs susceptible to reinitiation of IGSAC.
-(This is tested by including kinet-
- ically expanded tube samples in the test loops.)
Except in Lthis one respect,.the long term corrosion. tests have no rela-tionship to the adequacy of.the.kinetically expanded joint.
The tests were not designed to confirm that Licensee has pro--
vided reasonable assurance.against the possibility of mechan-lically induced tube ruptures caused by various transients, as alleged by Contention 1.a, and, in fact, the tests provide no
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information one way or the other on this subject.
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- Did the tests adequately. simulate operating condi-tions so as to provide reasonable assurance that corrosion will
.not'reinitiate?
5-A5. Lyes.
The long term corrosion test program includes tests which. closely simulate.the typical operating environment of the-steam generator tubing during steady state and transient
. conditions.
This program will enable Licensee to predict the l
. performance'of actual TMI-1. tubes in.the steam generators prior to return to' operation.
The program also includes comparative tests which closely. simulate OTSG operation but use tubes with high residual sulfur levels (non-peroxide cleaned) and expose
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- thentube samples to the contaminant which originally caused the IGSAC damage-(thiosulfate).
All tests simulated " worst case" chemistry. conditions for controlled contaminants (within chem-
-istry. specification limits).in order.to conservatively address the parameters known to influence stress assisted cracking.
In establishing operating parameters, to simulate both hot
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functional testing'(HFT) and subsequent operation, time periods were chosen of approximately 40 days for the HFT cycle and 66
. days for each of the six heatup/cooldown cycles expected in a year of operation.. The test loops are once-through in design, with primary coolant water chemistry flowing'on the inside of the tubes,.just as in the OTSGs.
The test' cycles allowed for r
periodic examination of test specimens to monitor for evidence f
of; corrosion damage.
All six heatup/cooldown cycles have been completed.
Final
.metallographic examinations of test specimens are now in L
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t JThis. program will enable Licensee to predict the g
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.'performancebof actual 4TMI-l tubes in.the steam generators prior
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'V itoireturn td' operation.
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JTEST PARAMETERS 1
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_The tests reproduced all'the. parameters which influence i
j IGS'AC;Si.e.,Jsusceptible material, environment, and stress.
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Sus'ceptible ' Material' i
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1Tolassure that?the',influenceiof prior operation and layup
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I onstubing'was adequatelyJrepresented, only tube-sections re-c 1.-
-movedtfrom'the TMI-l steam' generators were used.as specimens.
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iTheselspecimens.were-selected from various regions of each OTSG
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'Iincluding"tubk sections;which had;known' defects.
The use of
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,Jactual OTSC jtubes: precluded any possibility that test specimens i
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.t wouldfnot" duplicate' exactly the'TMI-l material.
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'The specificLtube sections for the long term corrosion 1
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1 (test were_ selected from-tubes.that had-been=previously removed-
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_from the< steam. generators for use-in-the failure analyses.
Within the-available material,.the-tube sections were selected i
to provide a' maximum = range of properties.
These included:.
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? Chimistry - test specimens were selected
.from representative heats of material re-
-moved'from the generator.
This provided a
- range of chemistry typical of most steam i
generator tubes.
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-Mechanical Properties' yield strengths'of the specimens spanned the range of those tubes present in the steam-generators.
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Materialususceptibility - specimens for i
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. testing-were selected from tubes which dis-l played various levels of susceptibility'to 3:
corrosion damage.
Some came from tubes
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.with no defects and others from tubes with 1
e up-to eight indications.
4-LThe. test' samples also.contain a representative sample of P
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-tubes _from various axial locations within each steam generator, ce
.The11argest portion of the' samples are from the upper tubesheet area', which contained the most defects.
There are also-samples lfrom-the lower face'of.the upper tubesheet, 15th tube span, and
, x-9th tube.' support plate areas.
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Subsequently, certain of the samples were subjected to-the u
1 explosive expansion process using mockup tube sheets and then
. subjected;to.a peroxide cleaning. process.
This ensured that E
the influence of these' processes on the inside surface condi-tion was produced.- Certain other samples were not peroxide.
(cleaned', in. order to-test what could occur if Licensee had not undertaken 7 the cleaning process;- given the larger quantities ~ of
- residual; sulfur-that would have remained on the tube surfaces.
s C-ring: samples madeLfrom actual TMI-1 tubes were also in--
scluded'in the-. test program'. 1These samples provided a means for-O metallographically examining test specimens during the testing
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- phase to look for any' microstructural changes or incipient cracking.
' Environment 44 Environmental chemistry parameters were selected to either
~simulate, or be more aggressive than, the water chemistry which willibe maintained in the-RCS.
In three of the four test l
loops,1100 ppb of'sul' fate, the maximum permitted under
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chemistry specifications, was used.
In the fourth test loop, 100 ppb thiosulfate was put in solution.
In addition, to en-b sure adequate conservatism, the levels of chloride and fluoride were set at the maximum amount permitted by Licensee's op-erating chemistry specifications (100 ppb each).
Because the testing and operation of the plant necessi-tates heating up and cooling down of the steam generators, the tests included typical temperature cycles.
Temperatures were raised from ambient temperature to the normal operating temper-ature of approximately 600*F.
Temperatures were held constant at operating temperature to assess any high temperature corro-sion phenomenon.
Periodically, the tests were cycled between 600*F and 500*F to simulate unit load changes.
The test loops were also subjected to cooldown cycles, some of which included the introduction of oxygen (as would occur when the RCS was open for inspection) and some of which did not (as would occur during normal shutdown).
These cycles provided the most rigorous test sequence in view of the fact that primary-side sulfur corrosion is a low temperature phenom-enon in which oxygen has a major influence.
Each HFT or operating cycle included a hold step for a minimum of one week in which the loop was aerated and main-tained at a temperature between 130* and 150*F.
This portion of the cycle simulated the aeration-temperature conditions which existed during the propagation of the original sulfur-induced IGSAC.
O Stress During heatup, operation, and cooldown, tubes in the actu-al OTSG undergo changes in stress.
A net axial tensile stress could exist in the tubes during cold shutdown and steady state operation.
The stress is reduced during heatup and increased during cooldown due to differential thermal expansion effects.
In order to simulate the changes in axial load, full tube specimens were loaded at a level corresponding to steady state loads during heatup, cold shutdown, and operation.
During cooldown, the loads were increased to approximate the maximum allowed cooldown rate.
Residual stresses induced by the explosive expansion are also a source of loads on the tubes.
Therefore, full tube specimens simulating repaired joints were kinetically expanded using the same process as in the actual steam generators to en-sure representative residual stresses.
These specimens were also exposed to the axial loads described above so that the t
worst case combination of loads was tested.
The C-ring specimens were intended to give an early indi-cation of possible problems.
Therefore, they were loaded to a level just slightly below yield, which is significantly higher than the load seen by the tubes in actual service.
This would make them more susceptible to IGSAC than are the actual OTSG
- tubes,
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SUMMARY
The long term. corrosion test program includes tests which i
. provide a valid simulation of the conditions that the OTSG j
tubing will experience'in future TMI-1 operations.
For compar-ison, tests have also been included which' simulate what could Loccur if Licensee had not taken the corrective measures of per-oxide cleaning and removal of possibl'e sources of-thiosulfate.
Parameters known to influence corrosion and more specifically i
ICSAC were reproduced to the greatest extent possible.
This test program provides a clear basis for empirically evaluating 4
steam generator tube performance over approximately a one year period.
E-f 9
IE PROFESSIONAL QUALIFICATIONS E-Don 1G Croneberger Director - Engineering & Design GPU Nuclear Corporation LGPU Experience:
Technical responsibility for the Mechanical, Electrical, Civil / Structural, Chemical, Radwaste and Materials Engineering support for.all nuclear generating stations for the GPU Systems.
1978 to 1980 was Manager - Design and later Manager -
" Engineering-&-Design with GPU Service Corporation.
Directed design engineering activities for all nuclear and fossil power
. generating facilities'and modifications assigned to GPUSC.
c Other Experience:
Prior. work experience included'a number of positions at
-Gilbert / Commonwealth during the period 1963 to 1978.
The last-position was Manager Structural Engineering.
It included technical 7 responsibility for structural engineering mechanics
'for.all nuclear and fossil. generating facilities.
Some of the other positions included Project Manager for balance of plant studies for a> liquid metal fast breeder reactor demonstration plant. - 'Other, positions as Project Structural-Engineer included a
responsibility for. technical supervision of' structural-engineering and engineering' mechanics for-a number of domestic nuclear power plants.- Earlier experience with the U.S. Navy
' included engineering and construction of radio telescope and 4
ancillary experience.
Industry affiliations have included the EPRI Steam Generator Owners Group, ASME Section~3 Division 2 (former Chairman) Land other industry nuclear standards activities including Nuclear Structures and Plant Design Against Missiles.
Education and training includes a B.S. degree in Civil lhtgineering from~ Pennsylvania State University, 1959.
Other technical training' includes. courses at U.C.L.A., M.I.T. and the University of Michigan.
I'have been involved in the Steam Generator-tube failure
. issue-from'the:beginning. :I provided. technical management
. oversight of failure analysis and repair activities.
Special emphasis was placed on understanding the mechanical design of the Steam Generators and applying that understanding to the repair program and the understanding of-the impact of the~ repair on the response of the components.
Jhr department provided engineering support in the areas of Materials Engineering / Failure Analysis,' Chemical Engineering and Chemistry, Mechanical Engineering and~ Engineering Mechanics.-
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r STATEMENT OF QUALIFICATIONS AND EXPERIENCE F. SCOTT GIACOBBE I, F. Scott Giacobbe, am employed by General Public Utilities-Nuclear Corporation as Manager, Materials Engineer-ing/ Failure Analysis.
I have been in this position since July of 1982.
My education includes a Bachelor's Degree in Mechanical Engineering from Villanova University in 1970 and a Master's Degree in Materials Engineering from Drexel University in 1975.
My work experience has provided me many years of direct involvement in the materials evaluation and failure analysis of power plant components; early *.n my career it also provided a very intense involvement in heat exchanger tubing evaluations.
In'1970, I began my employment with Westinghouse Electric Corporation in their Heat Transfer Division as a Materials En-gineer.
In'this position I worked on the materials selection, l
corrosion evaluations and failure analysis of heat exchanger
' components such as feedwater heaters, condensors, radioactive wasta evaporators and other secondary side heat exchangers.
In particular,.I was responsible for assuring that tubing utilized j
in the Westinghouse heat exchangers was properly specified and f
manufactured.
This function provided me with in-depth knowl-l v
edge of heat exchanger tubing fabrication practices, corrosion resistant properties and failure mechanisms.
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i In 1977-I left Westinghouse to join General Public
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Utilities as a Senior Engineer in their metallurgical laborato-i ry.
This position afforded me the opportunity to expand my I
areas of expertise to include materials selection, corrosion evaluation and' failure analysis of other components of both nu-l clear and' fossil' power plants, and to gain a broader under-J standing of. power plant operation.
In 1978 I was promoted to supervisor of the metallurgical laborato ry.
This was a first line supervising position which gave me the responsibility for the daily operation of the labo-ratory and supervision of the technicians and engineers re-porting to me.
This position also carried with it a large technical responsibility which kept me heavily involved in the i
day-to-day materials engineering problems.
My career took on a slight change in direction in 1980 when the company reorganized and formed the Nuclear Corpora-tion.
At that time I became Materials and Welding Manager in the Nuclear Assurance Division.
With this position I essen-tially had the same functions as before, with the added respon-sibility for welding at the nuclear power stations.
While in this position I was responsible for the technical and metallur-
'gical aspects of the development of the Nuclear Corporation welding program.
During this time I was still supervising all failure analysis activities, including the TMI spent fuel pool pipe cracking incident.
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In July 1982, another reorganization took place.
At this l
i time my section merged with the materials. engineering section in the Technical Functions Division and I took over management j
I of that newly formed section.
In this position I now had func-l tional responsibility for the materials configuration control l
- of both GPU nuclear power plants as well as welding engineering
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and failure analysis.
In addition, my section still provided I
failure analysis services to the fossil companies.
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I have been involved in the steam generator tube failure r
issue from the beginning.
I participated directly in the ini-l tial decision-making regarding the tube sampling and removal operations and was present to perform the initial visual evalu-t ations of the removed tubing.
I personally planned and oversaw l
the failure analysis activities performed by the outside la-boratories.
I also developed the corrosion testing programs which GPUN implemented to gain insight and understanding into the failure mechanism and responsible corredants.
It was also 1
7 my responsibility to coordinate the input from all our techni-cal consultants as well as plant experience and formulate the current failure scenario.
. During the steam generator repair, my section also provid-l, ed materials evaluation and consultation on all aspects of the l
repair including explosive expansion, flushing, peroxide l
l cleaning, and so forth.
My section also developed and imple-i mented the long term corrosion testing program and is l
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evaluating the results as the testing progresses.
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Lastly, during the course of the steam generator repairs, I was responsible for making all presentations to the NRC on corrosion testing and failure analysis activities.
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Over the years I have kept fully abreast with the state-of-tha-artsin.' corrosion technology through my attendance and participation in technical.taminars and conferences, and throdgh attending training aessions.
I am a member of the
.x Edison Electric-Institute Materials, Piping, Welding and Corro-sion Task Force, a group of industry representatives who meet to. share and develop solutions to corrosion problems in the
' field of materials and. welding in 'che power industry.
In addi-tion, I am a member of the American Society for Metals.
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% 9 Publications 1.
F. S. Giacobbe, "E$ amination ' Evaluation and Repair of Stress corrosion ^ Cracking' in a PWR Borsted Water Piping System", NACE Corrosion 81.
a 2.
F. S. Giacobbe,, J.D. Jones,f. R. L. I.ong, D. C.
$ lear, "Re-pairs of TMI-1 OTSC Tube Tallures" Plant / Operations Prog-ress AICHE, July 1983, Vol. 2, No. 3.
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