ML19320B122
| ML19320B122 | |
| Person / Time | |
|---|---|
| Site: | Fort Saint Vrain  |
| Issue date: | 07/02/1980 |
| From: | Swart F PUBLIC SERVICE CO. OF COLORADO |
| To: | Dircks W NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| References | |
| P-80202, NUDOCS 8007090333 | |
| Download: ML19320B122 (4) | |
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pubiic serme company oe cdedo July 2, 1980 Fort St. Vrain Unit No. 1 P-80202 Mr. William J. Dircks, Director Office of Nuclear Material and Safeguards U. S. Nuclear Regulatory Commission Washington, DC 20555 Docket No. 50-267
Subject:
Thorium Purification Facility
Dear Sir:
As you may know, the Fort St. Vrain Nuclear Generating Station uses a High Temperature Gas-Cooled Reactor (HTGR) and operates on a thorium-uranium fuel cycle. The fuel for this reactor is manufactured by General Atomic Company (GAC) and requires purified thorium oxide (Th0 )
7 as a feedstock to the GAC fuel fabrication facility.
In the past, this purified thorium oxide feedstock was supplied by Tennessee Nuclear Specialties (TNS).
TNS has decided to withdraw from the thorium processing business, and there appears to be no other domestic supplier of purified Th0 *2
/
As a result of this development, PSC has been investigating other options to obtain the purified Th0,, required for the continued operation of the Fort St. Vrain Nuclear GenePating Station.
One possibility, which appears attractive, is to locate a small facility at the Fort St.
Vrain site to perform the thorium processing operations previously perfomed by TNS.
PSC has been cooperating with a local chemical company, Boulder Scientific, in connection with such a facility.
PSC's representatives have visited TNS and reviewed the TNS process. As a result of this review, PSC believes that an improved processing facility based upon the TNS process could be safely operated at the Fort St.
Vrain site to meet the Th02 "**d' PSC presently possesses a source material license for thorium under License No. DPR-34 (Docket No. 50-267) as follows:
" Pursuant to the Act and 10 CFR Part 40, " Licensing of Source Material" to receive, possess, and use at any one time up to Y
25,000 kilograms of natural thorium in connection with operation O
of the facility."
O This quantity of natural thorium should be sufficient to cover both the Y
operation of the power plant and the production of the Th0,3 al though some modest increase in the licensed quantity may be desirable to avoid b rderline situations where the thorium in fuel fom and the thorium LOO 7090 being received, processed and shipped to GAC for fuel fabrication may pproach the 25,000 kilogram limit.
P-80202 July 2, 1980 Page 2 PSC requests that the NRC provide responses to the following questions:
1.
Based on 10CFR40.31(d), the proposed facility for thorium processing (as described below) appears to be an author Ized activity under PSC's current source material license. If so, what documentation of these planned activities, if any, would
- be required by the NRC to pennit PSC to proceed with the proposed facility?
2.
In order to ease the material flow situation, what would be required to increase the authorized amount of thorium to 30,000 kilograms?
3.
If the proposed thorium processing is not an authorized activity under PSC's current source material license, what actions must be taken to include it within the framework of the current license?
i Proposed Thorium Purification Process The proposed thorium purification process consists of the following steps:
1.
Dissolution of thorium nitrate, Th(NO )4, in wann water.
3 2.
Precipitation of thorium oxalate, Th(C 0 )g by the addition 73 i
of oxalic acid, 2H C 0.2H 0, to the s01UtTon.
224 2
3.
Separation of the thorium oxalate from the dilute nitric acid via a mechanical separator such as a centrifuge.
4.
Washing of the separated thorium oxalate with additional water and repeating the separation process to remove residual nitric acid.
5.
Drying and roasting of the thorium oxalate at a temperature of 1500*F to 1600*F in the presence of air to convert it to Th0 and CO '
2 2
6.
Packaging of the Th0 f r shipment to GAC for use in fabricating l
2 reload fuel elements
P-80202 July 2, 1980 Page 3 i
The thorium nitrate is received from the GSA in overpacked 55 gallon drums containing 825 pounds of thorium nitrate. When processed,_one drum of thorium nitrate will yield about 454 pounds (206 kg) of thorium oxide, containing about 181 kg of thorium source material.
It is anticipated that the proposed facility would process about two drums of
(
thorium nitrate or 362 kg of thorium per week. The feedstock thorium i
oxide for a reload fuel segment consists of about 8,000 kg and the facility would produce the required amount of purified thorium oxide in about 22 weeks, or about 5 months.
Based on a reload segment of fuel being required every one - to - two years, the thorium processing facility will be utilized between 21% and 42% of the time. When not in production the facility will be placed in a standby mode.
The equipment required for this relatively simple chemical conversion process would require about 1600 square feet of floor space.
It is proposed that the thorium processing take place in a separate dedicated building on or immediately adjacent to the Fort St. Vrian plant site.
Locating the facility at the Fort St. Vrain site offers certain significant advantages over other possible locations, including the following:
1.
The Fort St. Vrain site is located in a rural, low population area.
j 2.
Fort St. Vrain's physical security system and personnel can l
provide the required physical security for the facility.
l l
3.
Fort St. Vrain's health physics and radiochemistry personnel can provide the required health physics and radiochemistry coverage.
4.
Fort St. Vrain's quality assurance organization can provide the required quality assurance coverage.
5.
The contaminated laundry, personnel decontamination, and l
sanitary facilities of the Fort St. Vrain plant can be utilized by the thorium processing operation.
6.
The environmental characteristics of the Fort St. Vrain site are highly quantified in terms of; a.
Uses of adjacent land and water b.
Local population distributions and patterns c.
Geology d.
Seismology e.
Hydrology f.
Meteorology g.
Ecology h.
Local radiological and environmental monitoring
F P-80202 July 2, 1980 Page 4 The proposed thorium processing facility will be designed to the extent practical to provide essentially zero radiological effluent release.
The radionuclides of concern consist of Th-232 and its daughter products via the thorium decay series in addition to trace impurities from Th-230 and its daughter products from the uranium series.
In order to minimize release of these radionuclides to the environment, the processing circuit will be designed as a closed system.
Process vents will be collected, treated, and monitored prior to release to the environment.
Particular attention will be paid to the roasting oven and product packaging area to prevent release of Th02 particulates to the environment.
The wastes produced by the process will consist of less than one gallon of dilute nitric acid per kilogram of thorium proouct.
It is presently envisioned that this waste, which contains the majority of the daughter product activity, will be neutralized, solidified as concrete in drums, and shipped to an off-site low-level waste disposal area. Some pretreatment of this dilute nitric acid may be desirable to reduce the volume of solidified low-level waste.
Less than one gallon of waste wash water per kilogram of thorium product may also be produced during the processing operations.
It may be possible to recycle this water back into the process and eliminate the need for its consideration as a waste stream. This wash water will contain trace quantities of radioactivity and nitric acid.
If it is not feasible to recycle this water, it may have to be treated as waste.
l It is very likely that the very low levels of radioactivity in this wash water may allow its direct disposal after dilution by the plant l
cooling tower blowdown water.
In order to proceed with the fabrication of the next reload fuel segment for the Fort St. Vrain HTGR, GAC will need to initiate fabrication l
of the thorium-containing fertile particles by March 1 of next year.
This schedule requires that PSC have the proposed thorium processing facility in operation by the first of next year.
PSC would, therefore appreciate your response to this letter as soon as possible and by l
August 1 at the latest.
Very truly yours, yk M
/
Frederic E. Swart Nuclear Project Manager FES:pa cc: James R. Miller, NRC Darrell G. Eisenhut, NRC
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