ML19309G211
| ML19309G211 | |
| Person / Time | |
|---|---|
| Site: | 07105957 |
| Issue date: | 02/08/1980 |
| From: | Battelle Memorial Institute, COLUMBUS LABORATORIES |
| To: | |
| Shared Package | |
| ML19309G209 | List: |
| References | |
| 15933, NUDOCS 8005050136 | |
| Download: ML19309G211 (8) | |
Text
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N 3
RJB SAFETY ANALYSIS REPORT FOR SHIPMENT OF EPRI CRACK ARREST CAPSULES IN BMI-l SHIPPING CASK February 8,1980
\\
This Safety Analysis Report shows that the EPRI Crack Arrest Capsules shown in Figure 1 can be shipped in the BMI-l cask.
The capsules are essentially rectangular parallelepipeds made of aluminum and containing carbon steel specimens. Lesser amounts of other materials are present as shown in Table 1.
The six fission monitors consist of 0.25-in OD x 0.38-inch long stainless steel tubes containing either 12 mg of U 38 (3 monitors) or 20 mg of Np237 (3 monitors).
Each tube is sealed and fits into a steel dosimeter block which is sealed by welding. Because of the way in which the fissile material is encapsulated release into the cask cavity or to the environment is extremely remote. Moreover, the quantities are much less than the maximum release permitted by the proposed regulations (*).
The amount of U present 238 is 1.2 (10-0) curies and the amount of Np present is 4.2 (10-5)ci. The 37 maximum which can be released according to the proposed regulations is un-238 3
limited for U and 0.005 Ci for Np The activity of the capsules was determined with the computer code ORIGEN using the material quantities given in Table 1 and the irradiation parameters given in Table 2.
The resdits indicated that shortly after discharge ("30 to 60 min) the activity is about 5200 ci due entirely to isotopes in transport group IV.
Since the present license for the BMI-l cask permits up to 11,000 Ci of activity of materials in Transport Group IV the activity is within permissible levels.
The total decay heat generated by the capsule at discharge is 197 vatts.
The axial heat rate aver the height of the capsule is (197)(12)/21.5=
110 watts /ft. The cask is rated for contents whose decay heat is up to 1500 (a) Nuclear Regulatory Commission, Packaging of Radioactive Material for Transportation and Transportation of Radioactive Material Under Certain Conditions; Compatibility with IAEA Regulations, Proposed Rules 10 CFR 71, August, 1979.
15C33 e
2 TABLE 1.
MATERIALS IN THE EPRI CRACK ARREST CAPSULES Material Component Weight, lb Aluminum Capsule walls 68 Piping 5
Carbon Steel Specimens 123 Stainless Steel Seal Plugs, T/C (Type 304 and 347)
& Heater Sheath 10 Constantan Wire Thermocouples el Magnesium Oxide T/C Insulation 6
Nickel Heaters
^' 2 Inconel Heaters
^' 2 238 U
Fission Monitor 36 mg Np Fission Monitor 60 mg TABLE 2.
IRRADIATION PARAMETERS FOR EPRI CRACK ARREST CAPSULES Target Fluence (E > 1.0 Mev) 1 (1019) n/cm Fast Flux (E> 1.0 Mev) 2.2 (101 ) n/cm -sec 2
Thermal Flux 1.8 (1012) n/cm -sec 2
Fission in Fission Monitors 238 U
1.2 (1014) f/ dosimeter 237 Np 1.5 (1015) f/ dosimeter 2
e 3
watts.
The cavity length is 54 in.
Thus the axial teat rate permitted for the cask is (1500) (12)/54 = 333 watts /ft.
Thus, the decay heat is within permissible levels.
It was shown in the September 8, 1969 Addendum that for a 130 F ambient temperature and 1500 watt thermal Ivad, the outside wall temperature is about 190 F and the cask wall de is about 37 F.
For a 100 F ambient with 1500 watts decay heat the outside wall temperature would be 190-30 =
160 F.
For the reduced heat load of 110 watts /ft, the outside wall temperature would be approximataly (160-100) (110/333) + 100 = 120 F.
The fit through the cask wall would be (37) (110/333) = 12 F.
Thus, the cavity wall temperatura would be about 120 + 12 = 132 F.
These temperatures are conservatively high since they assume no radial heat flow in the cask wall.
The temperature of the capsule is calculated assuming that all cooling take place by convection and radiation. The capsule will be trans-ported without a canister. However, a wire mesh basket having a maximum vire size of 11 gage (0.125-inch) and minimum mesh size of 1.0 inches may be used to aid in handling the capsules.
The effect of the basket on the flow of decay heat will be negligible. Thus, it is assumed that convection and radiation heat transfer will take place directly between the capsule wall and the cask inner cavity wall, Figure 2.
In order to facilitate the calculations, it is assumed that the cavity wall is a plane, as wide as the capsule (14-in), as tall as the capsule (21.5 in), and located approximately 4 inches away.
From McAdams(*} the convection heat transfer correlation is given by Nu =
(Gr Pr)".
179 (L/x) where Nu
=
k distance between planes = 1/3 ft.
x =
k = fluid thermal conductivity L = height of planes = 1.79 ft 3
Gr = a x ;d t a = fluid property constants in Groshof Number (a) McAdams, W.
H.,
Heat Transmission, 3rd Ed. McGraw Hill, 1954, p 181 Eq 7-9 b.
l
4 Pr = Prandl number which is function of fluid property 4
For Gr > 2 (10 ); C = 0.071 and n = 1/3.
Thus h/k 0.0589 (a Pr) dt
=
Heat transfer by convection is expressed by Qcv "
A area of plane surface (14) (21.5)/144
=
=
2
= 2.09 ft h
coefficient from above correlation
=
Then 0.123 k (aPr)
At Q
=
cv Heat transfer by radiation is expressed by FeFa6A(T[-T2)
Q
=
where Fe - emissivity factor 1
1.+1_1 1
2 E
emissivity of capsule = 0.2
=
1 E
emissivity of cask wall = 0.5
=
2 d.167 Fe
=
view factor = 1.0 Fa
=
1.73 (10 ') R
~
7
=
2 A
2.09 ft
=
T capsule temperature, R
=
i y
cask cavity temperature, R T
=
2 6.04 (10-10) (T ' - T2) 4 Thus Q
=
y l
l It is assumed that the o e is about 200 F and that the mean air temperature between the capsule and the cask wall is about 230 F.
Then the l
air properties are l
l I
5 0.0188 Beu/hr ft F k
=
3 4.78 (10 ) / ft 7 a =
Pr = 0.68 460 + 132 + 200 = 792 R T
=
y 460 + 132 = 592 R T
=
2 Substituting the values in the equations above results in the following 186 Btu /hr Q
=
y 163 Btu /hr Q
=
r And the total heat flow is 349 Btu /hr = 102 watts.
Thus the capsule temperature for normal transportation is about 332 F.
It was shown in the September 8, 1969 SAR Amendment that for a full heat load of 1500 watts, and starting into the hypothetical fire accident from condition for a 130 F ambient temperature, the maximum cask cavity wall temperature during the incident is about 560 F.
Conservatively it is assumed that the fit from the cask wall to the capsule is the same as for the steady state condition.
Then the maximum capsule temperatue during the hypothetical aesident is 560 + (332 - 132) = 760 F.
This is well below the melting tem;2ratures for all the materials in the capsule.
The maximum temperature of 760 F is a conservative value for the following reasons:
(1) The starting conditions are for an ambient temperature of 1,30 F.
However, a 100 F ambient is allowed for determining starting conditions.
(2) The heat capacity of the capsule is neglected which will lower the maximum temperature in reality (3) The 21 t from the capsule to the cask cavity wall is assumed to be a constant over the temperature range. In reality radiation heat transfer will become more dominant at the higher temperatures resulting in lower maximum capsule temperatures.
The amount of fissile material present is inconsequential and thus a criticality evaluation is not required.
The above presentation indicates the adequacy of the BMI-l cask for che safe transport of the EPRI Crack Arrest Capsules.
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4Q s'
s' 14" 14.67" diagonal 4.34" n.
FIGURE 1.
CRACK APREST IRRADIATION CAPSULE
7 l ~
h l
Cavity 14 in.
ID=15.5'in-
"O"100hatts Q T 100 watts + -
4 i
I I
I a
f
.s
/
Assumed cavity plane for con-
"*C "C
II"E 2.17 in 4 in.
FIGURE 2.
SKETCH OF MODEL FOR HEAT FLOW FROM EPRI CRACK ARREST CAPSULE TO CAVITY WALL 15003
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