ML20052A761
| ML20052A761 | |
| Person / Time | |
|---|---|
| Site: | 07105942 |
| Issue date: | 04/08/1982 |
| From: | Cunningham G GENERAL ELECTRIC CO. |
| To: | Macdonald C NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| References | |
| 20577, NUDOCS 8204290139 | |
| Download: ML20052A761 (2) | |
Text
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GENERAL ELECTRIC COMPANY, P.O. BOX 460, PLEASAN 6FOR DIVIS1ON
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S Charles E. MacDonald, Chief
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U.S. Nuclear Regulatory Commission Washington, D.C.,
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- 1) Certificate of Compliance No
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- 2) Letter, GEC to C. E. MacDonald 1/15/82 1
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Dear Mr. MacDonald:
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On January 15, 1982, the General Electric Co. reported that, ry to our previous analyses for the G.E. Model 700 shipping container, it now appears that under the hypothetical fire accident conditions, the internal pressure for the " wet" shipments can exceed.100 psig with a resultant release of water. Ac-cordingly, General Electric has performed new analyses to demonstrate that the loss of coolant will have no adverse consequences on the container contents.
The thermal analyses were performed using the Transient Heat Transfer-Version D (THTD) computer code. THTD is a finite difference thermal analysis program which computes transient and steady-state temperatures for one to three dimen-sional heat trans fer problems. THTD permits input models with up to 2047 nodes with heat transfer from node-to-node or node-to-boundary by conduction, convec-tion, and/or thermal radiation.
For a 1500 watt heat load (the maximum permittgd for a " wet" shipment), the maxi-mum water temperature was calculated to be 224 F for normal conditions. This compares favorably with tests conducted in 1969.
In the 1969 tests, a 1500 watt heat load was placed in a dry Model 700. The hottest element was 270 watts, a value comparable to the maximum expected for an ETR (GETR) type fuel element.
0 The tests demonstrated a 240 F temperature rise between the dry cask inside surface and the hottest point on the 270 watt element.
For the hypothetical fire accident condition, THTD computed a peak temperature of 4110F for the inside of the cask. This assumed complete loss of coolant (i.e., a dry cask model was used), a 1500 watt heat load, and a 270 watt maxi-mum element.
By adding the 2420F temperature rise measured for the steady state condition to the 4110F cask tempe5ature during the hypothetical fire, a maximum fuel element temperature of 653 F may be predicted.
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GENER AL h ELECTRIC Charles E. MacDonald, Chief The 653 F temperature is well below the point at which damage would occur to the types of material that would be included in " wet" shipments in the Model 700.
For example, GETR type fuel which is a uranium-aluminum alloy has a melting temperature of 11000F. The temperature increase would not result in the release of any radioactive material from the Model 700 as fission products would remain in the fuel element matrix (Ref:
J.R. Tipton, " Reactor Handbook, Volume I, Materials", 2nd Edition, Interscience Publishers,1960; C. A..Bruch,
" Fission Gas Diffusion in the Uranium-Aluminum System", WASH-296,1956).
The ETR type element was chosen for this analysis because of the relatively low melting point of the aluminum-uranium alloy. The results, therefore, would be valid for other loadings contained in Certificate of Compliance No. 5294.
No release will result from mechanical damage to the cask contents as the contents are either loaded in tight fitting baskets to prevent movement and provide spacing or are provided with shoring as required by Certificate of Compliance No. 5294.
In view of the above, General Electric concludes that the loss of water from the Model 700 during the hypothetical fire will have no adverse effect on the cask contents and no modification to Certificate of Compliance No. 5294 is necessary. Accordingly, there should be no problem in resuming " wet" shipments.
Sincerely,
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G. E. Cunningham Sr. Licensing Engineer GEC:sg l
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