ML20205Q494

Discusses Concerns Raised by State of Tn Re Abundance of Naturally Occurring Radioactivity in Alchemie Processing. Enrichment of Naturally Occurring Radioisotopes Will Not Pose Significant Health Hazard

ML20205Q494
Person / Time
Site:	05000000, 05000603, 05000604
Issue date:	10/03/1988
From:	Clark A NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS)
To:	Swift J NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS)
References
NUDOCS 8811090256
Download: ML20205Q494 (3)

Text

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o . OCT 4 31988 MEMORANDUM FOR: Jerry J. Swift. Section Leader Advanced Fuel and Special Facilities Section Fuel Cycle Safety Branch FROM: A. Thomas Clark, Jr.

Advanced Fuel and Special Facilities Section Fuel Cycle Safety Branch

SUBJECT:

NATlqALLY OCLURRING RA010ACT!VITY Ih ALCHEMIE PROCESSING One of the cencercs raised by the State of Tennestee is related to the abundance of naturally occurring radini::tgas and the prospect for increasing isotopic ratios of the% rafiouotopen W stable isotcpes in the enriching process. More exactly, will the enri.:htng process yield quantities or concentrations of naturally occurring radioactive materials which could be a significant health hazard?

Jim Hammelman (SAN), and I have investigated this question and satisfied ourselves that the naturally occurring radioactive material will not be a significant health hazard. In the following paragraphs. I explain why in some detail.

First, let's consider carbon-14. We insisted that AlchemIE take a look at this naturally occurring radioisotope, primr.rily s?nce its abundance is much greater than all of the other racioisotopes. However, a simple physical fact precludes its enrichment in most instances. i.e., the fact that the carbon dtoms in organic compounds used to provide a gaseous form for processing in the centrifuges will apportion themselves i:hemically so that there will be essentially to change in isotopic ratio t!1roughout the enriching cascade.

There is no plan to enrich elemental caroo).

There are a total of twenty-two radioisotopes distributed among fourteen different elements in all of the elements AIChemIE is currently considering for enrichment. Unlike carbon-14, these radioisotopes are considered by physicists / cosmologists to be primordial, i.e., they are tart of the original process which created the universe (as is uranium), and are not in the state of equilibrium with production equalling loss as is carbon-14 Table 1 shows the radioisotopes, their half-lives, their naturr, abundance, the size of their mass at an arbitrary threshold quantity of 0.1 microcurie, and the mass on site. The threshold is arbitrary since the Commission does not regulate naturally occurring radioisotopus. However, I have considered the exerpt quantities of byproduct material as set forth in Schedule B of 10 CFR 30.71. As stated in 10 CFR 30.18. "Exempt quantities," "any person is exerpt from the requirements for a license" from the Federal government if they possess less than the quantities shown in Schedule B. j 8811090256 891003 V [ t PDR ADOCK0500g3 }

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Jerry J. Swift 2 OCT 0 3 tggg The exempt quantities shown in Schedule B vary from 0.1 microcurie to 1000 micrc ,uries. Therefore, I have selected the lower end of the scale.

0.1 microcurie, as a threshold.

A simple comparison of the inventory masses in Table 1 with the threshold masses indicates that in only one instance is the threshold exceeded, i.e.,

in the case of tellurium-123. The very conservative assumption has been made that the yearly production level is in inventory in process equipment at one time, which certainly is not the case. The tellurium-123 ca.,e was addressed by the applicant in a letter, dated June 9,1988, assuming 176 pounds of pure tellurium-123. The consequent dose was about 0.3 millirem. Of course, the actual atandance in the 176 pounds released from a feed cylinder would be 0.87 per cent. Moreover, the actual process inventories or withdrawal quantities, for which actual enrichment of tellurium-123 can take place, are much less than the 176 pounds.

On the basis of the above, both Jim Hamelman and I have concluded that the enrichment of naturally occurring radioisotopes will not pose a significant health hazard.

Original Signed Br A. Thomas Clark, Jr.

Advanced Fuel and Special Facilities Section Fuel Cycle Safety Branch Division of Industrial and Medical Nuclear Safety, hMSS

Enclosure:

As stated DISTRIBUTION: .- -

utetet Nos. 50 603

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DATE: /0/ 3/88 :ll/)/88 0FFICIAL RECORD COPY

. .'", . OCT 0 31988

.1 TABLE 1 NATURALLY OCCURRING RADI0 ISOTOPES THRESHOLD MASSES Mass. Kilograms Isotope' Half-Life Abundance Threshold Inventory (Yearly)

(years) (%)

Vanadium-50 6 x 10 15 0.25 84 .001 Cadmium-113 1.3 x 10 15 12.26 41 5:1 17 Cadmium-116 >10 7.58 3200 5.1 14 Indium-115 6 x 10 95.77 19 .001 Tellurium-123 1.2 x 10 13 0.87 0.41 2.8 Tellurium-130 8 x 10 20 34.49 2.9 x 10 7 2.8 12 Tantalum-180 10 0.0123 .050 .001 10 ~

Rhenium-187 4.3 x 10 62.93 .0022 .001 16 Germanite-76 >2 x 10 7.67 420 5.7 Molybdenum-92 >4 x 10 18 15.86 103000 70 M)1ybdenum-100 >3 x 10 17 9.62 8400 70 Platinum-190 6.9 x 10 11 0.0127 3.7

• 15

• Platinum-192 10 0.78 5400 15

• Platinum-198 >10 7.19 5500 Antimony-123 >1.3 x 10 16 42.75 44600 .001 17 Selenium-82 >10 9.19 23C000 .001 17 Tin-124 >2 x 10 5.98 690000 .018 Tungsten-180 >1.1 x 19 15 0.135 5500 .004 6

Tungsten-182 >2 x 10 17 26.4 1.02 x 10 .004 Tungstan-123 >1.1 x 10 17 14.4 560000 .004 Zinc-64 >8 x 10 15 48.49 14300 1000 15 Zinc-70 >10 0.62 1900 1000

• Quantity processed not shown, but would be similar to other noble metals

1. e. , <100 grams