ML20040G835
| ML20040G835 | |
| Person / Time | |
|---|---|
| Site: | 05000054 |
| Issue date: | 01/09/1982 |
| From: | Voth M UNION CARBIDE CORP. |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8202160520 | |
| Download: ML20040G835 (2) | |
Text
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o UNION CARBIDE CORPORATION MEDICAL PRODUCTS DIVISION P.O. BO X J2 4. T U X L OO, N E W YO R K 10987 T L LI PHONL ; 914-351 2131 E
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February 9, 1982
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'%, g Director of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, DC 20555 Attn: Chief, Operation Reactor Branch 4
Dear Sir:
On June 2, 1981 we submittted a request to amend License No. R-81, Docket No. 50-54. We wish to amend that request such that technical Specification 3.5.2.c (5) for the Union Carbide Nuclear Reactor read as follows:
(5) The lodine inventory of a single capsule shall be limited to 1000 Curies I-131 dose-equivalent.
This limit is twice that previously requested but is still within that justified in the June 2,1981 Safety Analysis.
In discussions with your representatives who are currently reviewing our amendment request, we understand that the gaseous fission product release fraction from the thin plating of uranium is a pivotal issue. Our Safety Analysis supports a fraction of a percent iodine release versus 100% as assumed previously. The requested increase in the iodine inventory limit is from 70 Curies to 1000 Curies or a factor of approximately 14. We wish to highlight the following factors in support of our request:
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U.S.N.R.C.
Director of Nuclear Reactor Reg. February 9, 1982 1.
The release mechanism for gaseous fission products is such that noble gases have a much greater release fraction than iodine; the release fraction of noble gas is certainly a conservative upper bound for the iodine release fraction.
2.
The fission product release rate from oxides is substantially reduced at lower oxide temperatures.
3.
The oxide temperature in a singly-encapsulated target in a water cooled reactor is substantially less than in a doubly-encapsulated target.
4.
Over 6800 doubly-encapsulated targets have been irradiated at our facility with no indication of elevated fission product release fractions.
5.
Measurements made at our facility on a typical, doubly-encapsulated target showed release fractions of 2,5% for noble gases and 0.1% for iodine.
6.
While most release fraction measurements reported in the literature are for oxide pellets or thicker oxide platings, they support the Union Carbide measurements.
7.
Using the measured noble gas release fraction from a doubly-encapsulated target (elevated oxide temperature) as a conservative upper limit for the iodine release fraction, a factor of 40 increase (2.5% vs 1004) is justified relative to the requested factor of 14.
Yours very truly, CD (f j CLAcvA.,
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s Marcus H. Voth Manager Nuclear Operations HiV:js l
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