Final draft Addendum to EEOICPA claim made by F. N. Case re Claudia F. Osborn.

Claudia F. Case, née Osborn, Y-12 Building 9206, 1946.

Cover Letter:

Mrs. Courtney Scarbrough Case Worker Energy Employees Compensation Resources Center Suite C-103, Jackson Plaza 800 Oak Ridge Turnpike Oak Ridge, TN 37830

Subject: Claim Interview Scarbrough/Case 9:00 a.m. 03-15-06

Ref.: Claudia F. Case: (Deceased Y-12 Chemical Operator)

I am enclosing the death certificate of Claudia F. Case and a discussion of her various work assignments while employed at the Y-12 Electromagnetic Uranium Isotope Separation Complex. This work history, as a chemical operator, in building 9203 and 9206 represents the major work activities over the period of employment.

Sincerely,

F. N. Case

Addendum:

General Overview of the Y -12 Operation:

The National Nuclear Energy Series: Chemical Processing Equipment: Electromagnetic Separation Process Division I - Volume 12: A secret report prepared in 1951 (now declassified) is a collection of papers written by various individuals responsible for the chemical process, development, and supervision of these operations to support the beta calutron uranium isotope process.

The beta calutron isotope separator was a batch type device which utilized uranium tetrachloride as a feed material. During a production run, approximately 10% of the feed batch yielded a U-235 product enriched to >80% for use in bomb fabrication, and approximately 90% of the feed was dispersed over the Beta Calutron components and the vacuum chamber liner which was dismantled and washed with nitric acid solution to recover this uranium fraction. The wash was processed as recycle material to convert it back to UCL4 for use in another calutron run. This chemical recycle was a major effort in the electromagnetic isotope separation of U-235.

The subject of the claim (Claudia F. Case) worked in the chemical recycle operation (page 15) of the above referenced "Nuclear Energy Series" Electromagnetic Separation Project preface is enclosed (Fig. 2) to indicate the uniqueness of this effort relative to the technology base of the nation at time. The requirements for secrecy made for a workforce, at the operational level, that had limited knowledge of the material with which they were working. (Fig. 2) is a partial index of the papers presented in Volume 12 of the National Nuclear Energy Series which provide greater detail of the chemical operations than will be discussed in this memo. (Fig. 3) is a listing of the beginning of various process operations between 1943 - 1946. This list shows the building completion date and the operation performed in the building.

BETA CHEMICAL RECYCLE BUILDINGS 9203 AND 9206 were the locations where the subject of this claim worked as a chemical operator. The subject of the claim's work assignments are shown for each work location; with a brief discussion of the production function of each location relative to the total uranium recycle that supported the Beta Calutron U-235 Isotope Separation to produce a highly enriched U-235 product.

BUILDING 9203:

Building 9203 became operational in October of 1943 and served as a pilot plant to develop the various chemical processes used in the Beta Chemical Recycle that supported the calutron separators. All of the unit processes for the Beta Chemical Recycle, except Calutron washing, were set using intermediate enriched U-235 product from the alpha calutron production which started in January 1944. This product contained approximately 30% U-235 using natural uranium feed and low enrichment feed from the K-25 Plant.

All of the unit processes: solution concentration by evaporation, solvent extraction purification of Calutron wash solutions, peroxide precipitation of solvent extraction solutions, conversion of U04 to U03 by calcination at high temperature, conversion of U03 to UCI4 by high temperature and pressure reaction with CCL4 Beta Calutron; Product U-235 recovery and product reduction to elemental uranium, were involved in the 9203 operations.

Building 9203 also served to train new employees to staff building 9206 when it became operational. The principal job assignments given the subject of this claim are discussed under four major headings.

A. Building 9203: Training and Conversion of U04 wet oxide cake to dry U03 powder.

B. Building 9206: Removal of wet U04 cake from centrifuge bowls.

C. Building 9206: Calcination of U04 to U03.

D. Building 9206: Recovery of Beta Calutron product receiver parts for reuse.

Building 9203 Work Assignment: (August 1944 - November 1944)

The subject of this claim (Claudia F. Case) was assigned to convert U04 wet cake obtained by hydrogen peroxide precipitation on uranium nitrate solutions to U03 by calcination at 500 - 550 c in an electric heated muffle furnace. The peroxide cake was contained in stainless steel trays approximately four inches deep by eight inches wide and twelve inches long. During the heating process the wet solids would form hard crusted lumps that had to be broken to insure uniform conversion of the U04 to U03 with a minimum conversion to U308 which was refractory to conversion to UCI4 produced in a separate operation by reacting U03 with UCL4 at high temperatures and pressure to yield UCL4 feed for the Beta Calutrons.

This breaking operation was accomplished by reaching a stainless rod into the open muffle furnace and with a crushing stirring motion reduce the oxide to a powder. During this stirring operation U03 fine particle size dust was discharged into the room environment, providing a high potential for respiratory ingestion and skin contamination. Operators had access to change room showers at the end of the work shift. There was no system in place for whole body contamination monitoring or for urine or fecal sampling during the time period 1944 - 1946.

B. Building 9206 Work Assignments:

Building 9206 was placed in operation in November 1944. Wet U04 was prepared by precipitation of Calutron Wash Solutions with hydrogen peroxide in the Beta Calutron Process Buildings. The U04 precipitate was recovered by centrifugation and transferred to building 9206 for conversion to UCL4 feed for isotope separation in the Beta Calutron. (Fig. 4} shows Sharples Centrifuge bowls used.

Approximately 50% of the work week time was spent in removing U04 cake from centrifuge bowls. This operation consisted of placing the stainless steel cylindrical shaped bowl on to a cleaning table where a scraper attached to a stainless rod was inserted into the bowl and the wet U04 was transferred into a ten inch diameter stainless vessel for conversion to U03.

Approximately 2,000 grams of uranium enriched to approximately 30% U-235 was placed in each calcining vessel. The weight of uranium was based on the net weight of the centrifuge bowl contents as received from the Beta Process Buildings.

The weight control was designed to preclude accumulation of sufficient enriched uranium in one location that could produce a nuclear reaction (critical mass). The bowl cleaning personnel were issued work uniforms of the type shown in (Fig. 5} which is a photo of chemical operators washing Beta Calutron units to recover uranium that was dispersed over the Calutron parts during an isotope separation run.

After removal of most of the U04 cake by scraping the centrifuge bowl, it was placed in a wash unit where nitric acid was sprayed into the inverted bowl and the remaining uranium as dissolved. This solution was collected and processed by H202 precipitation and added to the U04 process stream for conversion to U03. (Fig. 6).

The bowl cleaning was a close contact/hands on effort. Rubber gloves were worn for protection against nitric acid uranium solutions and U04 skin contamination. New uniforms were used at the start of each shift. Showers were available in change rooms. No routine monitoring of personnel by radiation detection instruments were made. Urine or fecal sampling were not made. Technical advances by the K-25 gaseous diffusion plant, made the Beta Calutron method for enriching U-235 obsolete after 1946 resulting in a mass layoff of many of the chemical operators employed in Building 9206.

C. Building 9206 Calcination of U04 to U03:

The conversion of U04 to U03 is described under the section A 9203 Operations. The 9206 operational difference was one of scale and equipment modifications. Calcination batch size in the 9203 pilot plant was 300 - 500 grams of U04 heated in open trays. The 9206 production operation utilized six large furnaces each holding two calcining reactors that contained 2,000 grams of 30% enriched uranium each.

U03 dust exposure to calcining operators was greater in the 9206 process due to quantities of U03 processed even though some progress was made in collecting the dust with small spot hoods at each of the calcination reactors. (Fig. 7) shows a photo of the 9206 calcination furnaces. The operator is breaking U03/U04 lumps in the calcination reactors. Insulating asbestos gloves protect against the hot calcination liner.

A filter queen vacuum cleaner was used to recover U03 dust from the room surfaces as it accumulated. Like the 9203 calcining operation, the U03 dust posed a significant respiratory ingestion potential. Approximately 36% of the weekly work time involved the calcining operation to convert U04 to U03.

D. Building 9206:

Recovery of Beta Calutron product graphite receiver parts for reuse. (Fig. 9) shows a drawing of the Beta Calutron receiver used to collect Uranium Isotopes U-238 and U-235 during a Calutron run. The recovery of certain parts of the Calutron product receiver for reuse was desirable as a cost advantage. This recovery required the removal of deposits of uranium deposited by the ionized uranium beam. This removal was carried out in an open faced vacuum hood where the graphite part was wire brushed with a power driven rotating brush. As with the calcining operation, the dust collection into the hood was not 100% effective and a portion of the graphite and uranium was discharged into the room where it became a potential for respiratory ingestion. Body contamination, arms, uniforms, fact contamination was apparent because the black graphite dust that accompanied the uranium was easily observable. Cotton gloves were worn by operators performing this operation which were salvaged to recover uranium.

One particular graphite part of the product receiver that was recovered was a graphite part called the defining carbon. The function of this part was to intercept the calutron ion beam that was present between the U-238 and U-235 beam. This beam carried most of the U-234 uranium isotope. Since this isotope was also enriched in the Alpha Calutron product, which became feed for the Beta Calutron Separation the concentration, of U-234 in the uranium on this defining graphite part was approximately 0.7% compared to a concentration of _% in natural uranium and is of biological significance. The work assignment represented approximately 10% of the weekly work time doing Calutron Product Receiver, Recovery.

Summary

The work assignments described in this memo are based upon my recall of events that occurred approximately sixty years ago. My position at the Y-12 plant was general foreman over the operations described and were under my supervision. I was also involved in the development of the processes used in these production operations. The National Nuclear Energy Series: Division I Volumes 7 and 12, A Secret Report which was a collection of papers authored by various individuals responsible for the electromagnetic separation of the uranium isotopes development processes and in many cases supervision of the production operations was used as guidance in this recalling of events. I was a contributing author to this series: paper 19: conversion of uranium hexafluoride to uranium trioxide (Volume 12 Division 1) and responsible for supervision of the operation during the 1945 - 1946 production operation. The National Nuclear Energy Series were declassified in 03-11-1960 (Authorization TID 1221.) Reference is made in the above discussion to "The National Nuclear Energy Series" with copies of pages that are included to verify statements made and as an aid in clarification of the scope of the work described.

The war time operations under my supervision comprised approximately one hundred people, working three shifts a day - seven days a week. Most had little experience in chemical operations prior to employment at the Y-12 plant and on job training for specific compartmentalized operations was practiced.

The conditions of tight war time security limited the information the operating personnel were given and most did not know that uranium isotopes were the materials being processed. All chemical reagents such as nitric acid etc. were identified by a number rather than a name.

While this lack of general information resulted in a few injuries, specific work procedures were adequate to make for successful achievement of production goals. The "National Nuclear Energy Series," while an excellent reference for equipment development and operating procedures, it gives little insight concerning the work level details as practiced and status of the monitoring of personnel exposed to uranium. Emphasis is placed upon the control of critical mass nuclear reactions, which is proper because of the extreme seriousness of such an event to personnel and project. Health physics monitoring and sensitive instrumentation was not well developed during the war time period.

The urgency to produce a military nuclear weapon capability was a first priority of the Manhattan Project. Current day processing procedures and health physics monitoring of nuclear operations is greatly improved over those practiced in the WWII time.