ML20213F923

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Rupture Test of Intentionally Damaged Alloy 600 Once- Through Steam Generator Tubing
ML20213F923
Person / Time
Site: Arkansas Nuclear Entergy icon.png
Issue date: 10/04/1977
From:
BABCOCK & WILCOX CO.
To:
Shared Package
ML20213F823 List:
References
LR:77:2341:71:1, NUDOCS 8611170249
Download: ML20213F923 (16)
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- CHEMISTRY & CORROSION, ARC ...,..

G. J. THEUS Cust*

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I8M - RUPTURE TESTS OF INTENTIONALLY DAMGED ALLOY 600 LT56 TIBING I OCT08ER 4, 1977 v ~ - . - . -,

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SU44ARY A :ee: ra jru- : .1eress t he effe:'t .l vari us defects in A::oy C::

e:ca acncratcr taina we carried cu: at t he A :

  • in c ?esea rch :en ter.

Y .~he rN;ra xnrie:ed :f a ceries of burs: tests of defe.-ted tubin.: ueiru k TE~ pa:ite a::er :: C ':"! A th ; resswre ? ctmen :00: .:nd b:.' rei.

7:~':crtice :l hr J.rx:p i Jee a: (02*F x rs a:s: de tsmined.

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D Distribution (COWANY L IMITED) This information is freely availeble to all N Comoany personnel . Written approval by sponsoring unit's R&D coordinator is required only if release outside of the Coreany is requested.

P. 5. Ayres - ARC G. Musat - ARC N M. J. Bell - NPGD, Lynchburg F. J. Pocock - ARC R. U. Blaser - ARC P. E . Sene met er - ARC

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F. R. Curke - NPGD, Lynchburo T. 5. Sprague/L. E. Spr/ - NED Barbertor E. E. Coulter - NEC, barberton H. 5. Swenson ARC N H. F. Dobel - MPGD. Lynchburg G. F. Tisinai - Beaver Falls

' Chemistry & Corrosion files (3)

H . A . Dossi a n - AR C

\ R. M. Douglass - Mt. Vernon Corporate Information Services G. h. Esenanuel - Mt. Vernon ARC Library (3)

% D. W. Koch - NED, Barberter. WPU L tbrary ici J. A. Manzi/E. M. Dorsey - ARC B. h. Mcdonald - MPGD. Lynchbura

\ T. A. McNary 8611170249 861031 PDR ADOCK 05000313 R. C. Ritschart!/J. V. Monter - ARC P PDR j

I B&W ma kes no warranty or repr esentation, empressed or implied e with respect to the accuracy. completeness, of usefulness of the infortnat'on contained in this report e that the use of any information, apparatus, method, or process disclosed in this report rnay not infringe privately owned rights.

B&W assumes no liability with respect to the use of, or for damages resulting f rom the use of eany inf ormation, apparatus, met t N, or process disclosed in this report e experimental apparatus f urnished with this report.

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The Alloy 600 tubing in steam generators may be affected by various damaging events. The tube wall may be worn if there is movement between the support plates and tubes. Intergranular stress corrosion cracking, or wastage attack of the tees may result from upsets in weter chemistry.

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Fatigue or other, as yet unidentified, mechanisms may also cause tee damage Should any of these events occur, it could pose a safety-related question if a main steam line break (MSLB) should subsequently occur with the loss of sesondary side pressure. The damaged tubes would have to withstand the entire primry coolant pressure (approximately 2500 psi) without rupturing. Therefore.

the purpcse of this prograr was to determine the extent of damage a tube can endure and still perfore satisfactorily in case of such an event.

I In order to establish the extent of

  • allowable" tube damage, a test program was conducted wherein intentionally daanged Alloy 600 OT56 tubes were subjected to various internal pressures. The specific objective

. of the test program was to deterrine whether or not tubes dessoed to 50%

of their wall thickness could withstand a MSLB incident. For coupleteness l of the test program, 600*F tensile properties of the damaged tubes were also determined. The results of a sirilar program on the collapse strength of intentionally damaged tubes in the event of a loss of coolant accident (LOCA) have already been reported.III

2. TEST PROGRAM 2.1 MTERIAL The material used was Alloy 600 OTSG tubing. Heat M5442, manufactured by t- Tubular Products Division of the Babcock & Wilcon Company. All tubing was stress relieved, ll50*F/18 hours, prior to testing. The actual dimensions of this tubing are 0.628' 00 x 0.038' wall. The analysis is )

given ir Table 1.

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Babcock &WWoom LR:77:2M1-71:1 Paem 3 Table 1. Analysis of Heat M5442 C .051 Cr 15.81 Fe 8.92 Mn .37 N1 74.01 Mg .037 5 .0063 Mo .07 Al .28 B .0018 Cu .02 Ti .25 Si .13 Co .045 Pb <.005 2.2 SPE CIME N5 Specimens were 6 in. long for rupture tests and 23 in. long for tensile tests. Defects were placed in the middle of the rupture test specimens. Defects in the tensile test specimens were placed in a location on the tube corresponding to the center of the tensile test furnace. The rupture test specimens were plugged at each end with Alloy 600 material. Alloy 600 tubing,1/4 in. 00,was inserted into a hole drilled in each end of the plug so pressurizing water could enter the specimen.

Undamaged tubes were used as comparison specimens in both rupture and tensile tests.

2.3 D_EFECT DEPTH The objective of the program is to assure satisfactory tube performance in case of an 'tSLB with tubes damaged such that only 50% of their wall rernained. Tubes with defect depths greater than 50% of the wall were tested to establish the relationship of defect depth and defect shape with rupture pressure. Tubes with defect depths less than 50% of the remaining wall were tested to coaclete the test array.

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o M&h L A:77:!M1-71:1 Paan 4 The defect depths used for each defect geometry were:

1) 1001(0.038") of tdHe well roamining (no defect)
2) 751 (0.0285*) of tube wall remaining
3) 501 (0.019") of tube wall remaining
4) y)t (0.0114") of tube wall remaining 2.4 DEFECT GEOMETRY l

Mc specimen of each defect gemetry/ defect depth costination of interest was tested in the rupture test and in the 600*F tensile test.

The various defect types are described and illustrated below.

i e Longitudinal Slit A longitudinal groove 0.010" wide and I" long, was machined in the outside surface of the tube with a milling cutter. This defect simulated a longitudinal crack in the tube wall.

e 120* Circeferential Slit A slit defect groove. 0.010" wide and extending around 120" of the circaference was machined in the outside surface of the tube with a milling cutter. This defect simulated a partial cirewferential crack in the tube wall.

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N'h LR:77:!M1-71:1 Pese 5 e 360' Circumferential Slit A slit defect groove. 0.010" wide and extending completely around the circumference was :.a:hined in the outside sur' ace of a tee with a milling cutter. This defect simulated a couplete circumferential crack in the tube wall.

o Circumferential Thinning A 360* area of uniform thinning. 0.5" wide, was machiped on the outside surface of the tube. This defect simulated an area of uniforr thinning of the tube wall.

E e Flat Defect A flat spot, 0.75" long, was introduced on the tse well by machining o+ the metal . This defect simulated areas thinned by sechanical wear.

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Butxed C -- LR:77:tyl.71:1 Paet 6 2.5 TEST ConDIT1016_

8tupture Tests Each rupture test was conducted at 600*F for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> at each pressure which varied, in 500 pst increments, between 1000 psi and 5000 psi.

The tubular specimens were pressurized with water of 0TSG feeesater qality (Table :).

Table 2. Pressurizing Water Chemistry pH 9 25*C 9.3-9.5 (IsH3 )

Conduc tivi ty 4-10 u shos/cm Oxygen 0 (residual hydrazine)

Iron <5 ppb Tempera tcre 600*F (316*C)

Prior to testing, the diameter of each specimen was measured at four points (45* apart) on the circumference at the site of the defect.

The specimens were then installed in a specially designed test fixture (Figure 1) which was placed into an autoclave. After the test fixture was secured in the autoclave, water was pumped into the specimens through the 1/4" 00 Alloy 600 tubino to a static pressure of 1000 psi. The temperature of the autoclave was raised to 600*F and the specimens held under these conditions for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. After 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, the pressure was l

raised to 1500 psi and held fo- another 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. This procedure was repeated at 500 psi increments until 5000 psi was attained. In the case of specimen failure, that specimen was valved off from the rest of the specimens and testing proceeded.

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Babco_ck& Wdcox L p : 77 : 2341- 71 :1 Page 7

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Babcock & h LR:77:r M1 71:1 Paae 8 At the end of the test (after 5000 psi for 24 howrs), the specimens were removed from the fixture and rammasured at the same locations as previously described to determine swelling.

Tensile Tests All tensile tests were done in accordance Wth ASTM designation E21-70. Elevated Teeperature Tensile Tests of Metallic Materials.

3. RESULTS AND DISCUSSION Rupture Tests i

Rupture test results are summarized in Table 3.

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LA:77:fM1 71:1 y- to Table 3. Tube Retre tota (0.628* 00 x 0.038" Wall Alloy 600. Heat M5442. N111 Annealed + 1190F/18 hr)

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Tensile Tests Results of the 600*F tensile tests are given in Table 4. Tabulated are:

1. The yield strength and ultimate tensile strength of the desaged tubes and the undamaged tube based on the actual cross section area.

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4. CgcLg}ggg The results of 600*F burst and tensile tests of intentionally daseged Alloy 600 OTW tubing leads to the following conclusions: -

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5. ACIMMIDBENf3 i R. C. Ritschard, J. A. Menti J. V. Monter, and E. M. Detsey of the ARC Chemistry & Corrosion Section set up and conducted the tests.

Tensile tests were done by J. Rochus of the ARC Meta 11ery Section.

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R. H. Emanue son G. J. Thous /

RHE/WT/dj Attach.

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1. R. H. Emanuelson and G. J. Thous. " Collapse Tests en Intentionally Dasaged Alloy 600 0T56 Tubing". Alliance Research Center LR:76:2341-74:1. April 26,1976.
2. Metals Haneook, 8th Edition. Volume 10 Failure Analyses and Prevention. American Society for Metals. Metals Park. Ohio, 1975, p. 64.

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