ML031110212

Memo to M. Kirk from P. T. Williams and B. Bass, Regarding Status Report on Davis Besse Analyses

ML031110212
Person / Time
Site:	Davis Besse
Issue date:	10/04/2002
From:	Bass B, Williams P - No Known Affiliation
To:	Matthew Kirk Office of Nuclear Regulatory Research
References
FOIA/PA-2003-0018
Download: ML031110212 (9)

Text

MEMO DATE: 4 October 2002 TO: M.T.Kirk FROM: P. T. Williams and B. R. Bass

SUBJECT:

Status Report on Davis-Besse Analyses The attached Figs. 1-6 provide a summary of the Davis-Besse analyses performed to date under the new Task 9 of JCN Y6533. In Fig. 1, the cladding properties used in the current study are presented:

(a) true stress versus true strain and (b) thermal expansion coefficient versus temperature. The remaining figures address a specific sub-task described in the workscope for Task 9.

Sub-task 9.1D requires an estimate for crack driving forces as a function of flaw size and applied membrane stress in cladding.

Figure 2 depicts the first step carried out in preparation for the J-integral analyses, i.e., calculation of an updated estimate of the exposed cladding "footprint" based on the recent "dental mold" cast from the D-B cavity. That footprint area was estimated to be 28.23 in2 . Comparisons of the latest "footprint" statistics with previous ORNL interpretations are given in the table of Fig. 2(b).

The newly calculated "footprint" area was used to define a burst disk having the same cross-sectional area.

Table I presents ductile tearing data for three-wire series-arc stainless steel weld overlay cladding published in NUREG/CR-5511 [1]. The ductile-tearing data presented in Table I are plotted as a function of temperature in Fig. 3.

Figure 4 presents the three finite-element models developed for this phase of the analysis. For a constant flaw length, surface breaking flaws were centrally located in each burst disk. The three relative flaw depths investigated were 0.5, 0.25, and 0.05. The constant total flaw length was 2.0 inches (50.8 mm).

Each of the three models were loaded with an increasing lateral pressure until the solution approached a numerical breakdown. The resulting J-integral loading paths for the three models are shown in Fig. 5. Figure 5 also presents a value of J1, for a temperature of 318.3 'C (605 'F) estimated by extrapolating from the data in Fig. 3a using a 4th order polynomial curve-fit.

Figure 6 compares the critical pressures (determined from the results shown in Fig. 5) for two potential failure modes of the burst-disk models. The ductile-tearing critical pressure is calculated from the point at which the load path for each flaw crosses the J1, line in Fig. 5. The plastic-collapse critical pressure was estimated from the load at which each model began to approach a numerical instability in the analysis. From the curves in Fig. 6, the controlling failure mode for the two larger flaws in the current study was ductile tearing. The shallow flaw (aft = 0.05) was close to the J1, line when it began to fail by plastic collapse. An estimate of the applied tearing modulus was calculated using the data from the three flaws at a pressure of 6.4 MPa (0.928 ksi).

As indicated by the comparison in Fig. 3b, this estimate of the applied tearing modulus indicates a stable ductile tearing for the largest flaw, thus implying stable tearing for the smaller flaws as well. C 1

References

[1] F.M. Haggag, W. R. Corwin, and R. K. Nanstad, IrradiationEffects on Strength and Toughness of Three-Wire Series-Arc Stainless Steel Weld Overlay Cladding, NUREGICR-55 11 (ORNL/TM-1 1439), Oak Ridge National Laboratory, February 1990.

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Table 1. Ductile Tearing Data Extracted from Table 13 of NUREG/CR-5511.

Tests.-.

CA . s Terin UnirradiatedSpecimens A13G -75 117 64 H2 -75 137 49 Al1Ba 20 165 270 A13D 20 134 209 AlOG 20 171 176 AlOE 120 128 246 H5 120 119 229 H3 120 120 232 A13Fa 120 159 359 H6 200 90 240 H4 200 111 231 A15D 288 77 267 A13C 288 66 170 H1 288 82 192 Irradiated Specimens A15F -75 78 40 A15G -75 56 36 A13A 30 144 177 A15C 50 124 146 AlOF 120 94 175 Al5A 288 25 191 aSpecimen was not side-grooved, while all other specimens in table were side-grooved 20%.

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80 70 l '500 7n 70 G=94.36£ (ksi) 2000 IL 20 'i E = 25570.85 ksil 1100 0 io0 0 0.05 0.1 0.15 0.2 00 (a) Total Strain (- 09'2712002.K3 ptw 1.5 104 r- --- ;_ ------ ~ ~-- -----

L 1.4 105~-

u 1.314 1.1 i ii 0 500 1000 1500 2000 2500 3000 0912712002 K2 ptw (b) Temperature (0F)

Fig. 1. Cladding properties used in the current study: (a) true stress vs true strain and (b) thermal expansion coefficient.

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I 3

II "Footprint 9/2312002 1 Area = 28.23 in.2 /

R31 .712 (a)

.... t ,.,$.,.-.. l = T a w I Sowing FM" I 7I t I -

IdM HI

'Y.

IPIMXVWElhudaxa I. , -r " ,

't , 4 -,, 1

- 4I

,,-,: f~ -sr l~w7 i')><*<m C- -If It 1-1) >b r.I , e <^:.- '> n. n1 ->f Ai-FomdFoolmm 1 3536 3036 164122 -01194 9889 9699.33 -11716 75.26 19741 <09004..04351> <04351,09004>

Adj.sIed Foolpnnt 0.25In 40 06 31 78 16.4301 4..1255 12902 11031.S1-14135 99 00 245 71 <0.8943-04476> <04476,08943>

for Boundmig "ocpon A.-Found Foopuns 1 28 23 24.55 IS 332 40189 95.56 670863 -50 52 54 01 11307 IO.SSS 0.8301 1408300 SSSI 912Vo2 .1 Foolpnnt centroid is in glbbl coordinales Gbbal coordmnawe ristem has .-s alizgned h thefneeca] c-meee of rhe seosel The -y plane of the global coordinte sysiem is a hMIzontal plae (b) wth te xn-ss along She hoe between theceotsnocs of Nozzles 3 and II Fig. 2. Latest footprint estimated from "dental mold".

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Temperature (°F) 0 200 400 600 180 -- ______,,___.__.__ ____._...____,_...._. ..... __. ------- - --'-T ------- ----

10 0.96 Data from Table 13 160 -- (unirradiated) IN NUREG/CR-5511 I-0.88 C I(_

Nm i en E 140 - -' 0.8 .2 0

0 x

I',

.9 - 0.72 r-120 - 0 a

0.6 ii-1 0.64 _>1 100 -

• 0.56

, 0.48 80 -

-1 0.4 60 ----

-100 0 100 200 300 400 10/0412002 K2 pt'w (a) Temperature (°C)

Temperature (°F) 0 200 400 600 400

. Data from Table 13 350 - (unirradiated)

NUREG/CR-551 1 (n 300 L 0

250 -

0)

- /

• 200 L

.j_

150 , / Applied Tearing Modulus at 6.4 MPa (0.928 ksi) 100 2L = 50.8 mm (2.0 inches) -

t = 6.35 mm (0.25 inches) 50 H o0

-100 0 100 200 300 400 10/0412002.K3 ptw (b) Temperature (°C)

Fig. 3. Ductile tearing data for three-wire series stainless steel weld overlay cladding from Table 13 of NUREG/CR-5511: (a) J1, data from unirradiated specimens and (b) tearing modulus data from unirradiated specimens 6

Fixed-Grip Boundary on Outer Edge

-3 175 .. (U 125.) 2LI -16

• - 6 3I mu (O24 i.L)

L 254 .m (10 In.)

11- 76 IhXI .m (2 9g76 In)

An-. - 18226.4 mm 2.23X"bW)

(a) ' irv,-

Fixed-Grip Boundary on Outer Edge

~~~~~

1 . 1 052.2 502 E 2U.s- 32 IM75 mm (0 0625 Ii).

z x\Ma*t6.34 "n, tu 2CIn)

If -701615mm (2L.961n A(b - IU224 mm! (282124In ')

Fixed-Grip Boundary on Outer Edge pL.- 16202 0.10llS, lt mm(02125 A. _2,22i.4 ._ (22H-7h I1.)

5zA_ A l22&4mn'12.25 1.)

__W Fig. 4. Finite-element models used in calculating applied J-integrals produced by pressure loading of burst disk: (a) Model 1 (alt = 0.5, 2L/a = 16) (b) Model 2 (alt = 0.25, 2LIa =

32), and (c) Model 3 (a/t = 0.05, 2Lla = 160) (Task 9.1D) 7

Pressure (ksi) 0 1 2 3 4 5 6 7 8 600 F 3.2 500 2.8 N

N 2.4 -

E 400 2 I on 300 1.6 X

'a c-1.2 C 200 0.8 100 0.4 0 0 0 10 20 30 40 50 60 10/0412002.K1 ptw Pressure (MPa)

Fig. 5. J-integral driving forces from three finite-element models as a function of applied pressure.

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60 I i i 2L = 50.8 mm (2.0 inches) t = 6.35 mm (0.25 inches) -

8 50 H I_,

7 ^

0

.b_

0

v. Plastic Collapse 6 C 401-

'I 0 0 (a

a.

0~ 5 0e-AL 30 I- ,.

a., 4 Ii ra-U 20 Set-point pressure T.aOperatrnipressure J 3 U 10 1 -- _-.

Ductile Tearing

- i 2 1

0 0 0 0.1 0.2 0.3 0.4 0.5 0.6 alt 1AI/I'l2nnA2 VA nthA Fig. 6. Comparison of critical pressures for two failure modes as a function of relative flaw depth. The same flaw length (50.8 mm) is used for all current analyses.

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