%MurNBoperating022553; ]> Memorandum on Operating Plans for the Raleigh Research Reactor Machine readable transcription Beck, Clifford K. Creation of machine-readable version: Russell S. Koonts Creation of digital images: Russell S. Koonts Conversion to TEI.2-conformant markup: Russell S. Koonts ca. 29 kilobytes NCSU Libraries Raleigh, NC Modern English, MurNBoperating022553

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 02 November, 2000

Nuclear Reactor Digitization Project

Raymond L. Murray Reactor Project Notebook

 Illustrations have been included from the print version. Scanned by Russell Koonts with Photoshop 5.0 software. Memorandum on Operating Plans for the Raleigh Research Reactor Clifford K. Beck

15 pp. Manuscript copy consulted UA 025.16

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Library of Congress Subject Headings February 25, 1953 English LCSH manuscript 24-bit color: 400 dpi Memorandum on Operating Plans for the Raleigh Research Reactor Typescript 15 pp. February 25, 1953 MurNBoperating022553

R L Murray NCSC-59 This is Copy 9 of 50 Series A.

MEMORANDUM ON<lb/> OPERATING PLANS FOR THE<lb/> <name type="corporate"><hi rend="underline">RALEIGH RESEARCH REACTOR</hi></name>

Clifford K. Beck February 25, 1953

Department of Physics School of Engineering North Carolina State College Raleigh, North Carolina

MEMORANDUM ON<lb/> OPERATING PLANS FOR THE<lb/> <hi rend="underline"><name type="corporate">RALEIGH RESEARCH REACTOR</name></hi>

Clifford Beck February 25, 1953

Introduction To expedite the formation of a suitable contractual relation- ship between the Atomic Energy Commission and North Carolina State College on the operation of the 10 Kilowatt nuclear reactor now nearing completion on the campus, the Reactor Branch of the Atomic Energy Commission Research Division at Oak Ridge requested that the anticipated procedures on several phases of reactor operation be described. Such descriptions are given below.

Two anticipated uses of the reactor have guided the development of this project from the outset: 1.) Its use as a tool in the training of Nuclear Engineers, and 2.) its use by students and staff as a tool in college research projects of many types. To the end that the training objective could best be realized, the project has been maintained on a completely unclassified basis. To the end that the reactor could be used to maximum advantage in the usual university research pattern, the project has been maintained as free of control and direction from outside the college as possible. The Atomic Energy Commission has, from the first, given encouragement and support to these principles and objectives.

The descriptions and discussions presented below, most of which have been treated also in earlier reports, are in general consistent with the ideas above and with the important additional concept that

certain responsibilities in the operation of any reactor are allocated by law to the Atomic Energy Commission and cannot be delegated.

Financial Status The Raleigh Research Reactor was designed and constructed primar- ily by members of the Physics Department at State College. These stall members were concurrently responsible, also, for regular instructional and administrative duties in the department, as are any members of the College staff. Their salaries were paid from regular college budgets. The operation and use of the reactor, in large part, will be on the same basis. The reactor will simply be another tool in the department, used as other instruments are used, such as spectrographs, X-ray apparatus, etc. The number of men on the staff has been increased to handle these duties (and the increasing number of students).

In addition, certain technicians, expected not to exceed four in number at least during the first year or so, will be engaged for full-time work on the reactor facility. Funds for these persons will come from grants and from sponsored research projects.

The approximate total expenditures on the Raleigh Research Reactor and its associated Reactor Laboratory Building, up to the time of initial operation of the reactor, are: 1. For design studies, development of plans, travel, detailed design, construction of the nuclear reactor and purchase of all the directly attached auxiliary equipment - $100,000. 2. For Design and Construction of the Nuclear Laboratory Building - 400,000. 3. For completing facilities and providing equipment in the Nuclear Laboratory Building - 120,000. TOTAL (excluding most staff salaries except during 2 summer periods) - $620,000.

After the reactor has been brought to initial operating condition in the Spring or early Summer of 1953, a fund of $35,000 will become available, to be used over the ensuing two years. This fund will pro- vide for operation of the reactor during the period when most of the efforts will go toward calibration and adjustment of the reactor and determination of its operating characteristics. During this period, also, use of the reactor in experimental projects will be started. It is expected that a portion of the research projects utilizing the re- actor will be of "sponsored contract" nature, from which part of the finances needed to operate the facility will be obtained. The re- mainder will be obtained from regular college budgets and from grants from interested organizations.

SF Safety and Accountability The 999 grams of U235, as (highly enriched) Uranyl Sulfate, needed as fuel in the reactor will be received as a concentrated liquid solution, (700 grams/liter). When received, this material will be stored in a basement room of the Reactor Building inside a large heavy walled, combination-locked safe (2600 pounds). The basement room has only one door, and this opens into the Reactor Room in which the reactor is located.

Shipment of the uranium to Raleigh will not be requested until the reactor is ready, and its transfer into the reactor should proceed promptly after its receipt. The portion of the fuel not required at once in the reactor, for the low level operation anticipated for an initial exploratory period, will be stored in the locked safe mentioned above. Any samples subsequently withdrawn from the reactor for analy- sis likewise will be stored in the cabinet. If, due to some unan- ticipated event, it becomes necessary to remove all the fuel from the reactor, withdrawal into "always safe" shielded containers will be made, and these will be stored in the locked cabinet.

The fuel container of the reactor assembly is at the center of a 5-foot cube of close-fitting graphite bars. The graphite is sur- rounded by a 4" layer of lead bricks, and these, in turn, by 2 to 6 feet of concrete. Portions of the concrete assembly can be disas- sembled as blocks, of 3 to 6 tons each, by a 6 ton-capacity, overhead crane. The blocks are interlocked together, by a mechanism which prevents the removal of any one block until interlocking bars are withdrawn. The interlocking mechanism is located in the interior of the concrete assembly, behind a heavy "burglar-proof" 3" thick hard- ened steel, combination-locked, safe-door. When the building is not in use, the power to the crane will be turned off and this switch also will be locked.

Seven 3" to diameter horizontal "exposure port" tubes lead from the outer surface of the concrete shield to the surface of the reactor envelope, a 1/16" thick aluminum sheath close-fitted around the stainless steel fuel container. One 1" vertical tube extends from a locked steel box embedded in the top surface of the concrete shield downward to the fuel container and, as a welded-in re-entrant thimble, several inches down inside the fuel container. All these tubes may be used as channels through which beams of radiation can be conducted out of the assembly into external apparatus, or through which samples can be admitted into the vicinity of the reactor for high irradiation. When not in use each tube is filled with close- fitting concrete plugs. The exterior end of each tube terminates is a built-in safe-door assembly with a 3" - 6" diameter "burglar-proof" 3" thick hardened steel, combination-locked, safe door.

For initial admission of the liquid Uranyl Sulfate fuel solution to the reactor and for subsequent removal of liquid samples for analysis, two parallel 3/16" stainless steel tubes are provided. The

tubes connect to the fuel cylinder itself, one at the bottom and the other 2" from the top, and extend upward to their valve-closed termi- nals, located in a small steel box built into the concrete on the top of the reactor shield. The built-in steel box has a heavy steel lid which locks in closed position by a 3" thick hardened steel, combi- nation-locked, safe door, If the safe door is unlocked and the lid opened, the valved ends of the two "sample tubes" may be seen. A funnel apparatus may be connected to the tubes and extra solution added to the reactor core by gravity flow. A suction pump apparatus may be connected to the tubes for withdrawal of a fuel sample.

Thus, once the reactor fuel is charged into the reactor cylinder, subsequent access to the fuel itself, or to port holes leading into the vicinity of the reactor core, or to the interlocking mechanism which prevents disassembly of the massive shielding blocks, is guarded by heavy steel, combination locked, safe doors. In addition, the switch which supplies power to the crane is locked and all doors leading into the Reactor Room are provided with special looks. These special door locks may be operated only by simultaneous application of a key .and an electric signal from a button on the control oper- ator's desk in the Control Room. Power to the control desk, in turn, is obtained only through switches which are normally locked when not in use. The exterior doors of the Reactor Building itself will be locked when the building is not in use.

When the uranium fuel is received from Oak Ridge, gravimetric methods will be used to separate known portions for incremental addition to the reactor. Careful records of the total amount of U235 in the reactor will be kept. From time to time, samples of fuel may be withdrawn for analysis (pH, corrosion impurity, etc.), and additions or withdrawals of fuel may be necessary for various

experimental procedures. When such changes are made, careful records will be kept, both of the amount in the reactor, and the relatively small amount of that in storage.

This SF material will be used only as fuel in the reactor, and hence the only losses anticipated are those involved in handling and transferring from one container to another, and in/possible accidental spillage Contamination and loss, such as might occur for example in chemical manipulations, are not involved. It is expected, therefore, that the losses can be kept to negligible proportions.

Since the Uranium U235 will be all of a single chemical compound, will normally in major part be in the reactor, with possibly a small portion in storage, and will not itself be utilized in chemical or physical experimental manipulations, frequent inventories should not be necessary. It is proposed that one complete inventory be made each year, in which samples from each separate container be analyzed. and careful estimation be made of the quantity of U in the reactor and in each separate container. No provision has been made at North Carolina State College for isotopic analysis of Uranium, but if it were deemed necessary in this annual inventory, samples could be furnished the A.E.C. for isotopic analysis. It is anticipated, how- ever, that the probability of contaminating the fuel with Uranium of lower enrichment will be very small. Furthermore, the reactivity of the reactor, itself, after its characteristics have been determined, should provide a good indication of the enrichment.

In addition to the complete annual inventory, it is proposed that quarterly inventories of U235 be made. In these, quantities would be determined by physical inspection, counting of containers, and exam- ination of log records, but not by analysis and measurement unless "unknown" samples were involved.

Safety Precautions in Reactor Operation A. During Start-Up

"Start-up" refers to the loading of the reactor to criticality and the subsequent operation at essentially zero power level, during which many of the characteristics of the reactor can be explored. Only a negligible excess of Uranium above the critical amount at room temperature will be in the reactor for these experiments. During this period, pulse counting equipment must be used for operation and con- trol, since the levels of radiation are too low to permit use of ion- current equipment. The level will also be too low to permit use of the automatic control mechanism, hence operation will be by manual control.

The following instruments have been provided for use during this period of approach to criticality and low-level operation. It is intended that all of these instruments be available, but a minimum of 5 must be in good functioning condition during any attempted operation of the reactor.

1. BF3 proportional counter, feeding into a scaler equipped timer and mechanical register, thence into a rate meter equipped with tripping mechanism for excessive counting rates, thence into a recorder. 2. B-10 lined proportional counter, feeding identical to the above. 3. B-10 lined proportional counter, feeding equipped with timer and register. 4. U-235 lined fission chamber connected to and recorder. 5. Scintillation counter, chiefly sensitive to gamma rays, connected into; a fast amplifier and a fast tripping

mechanism for excessive levels. 6. B-10 lined graphite ion-current chamber (PCP) feeding into a 6 decade logarithmic amplifier connected to a recorder, and thence into a period measuring circuit, also connected to a. recorder. 7. B-10 lined graphite ion-current chamber (PCP), feeding through a range selector switch directly into a galvanometer.

In the approach to criticality and during the entire "start-up" period of low-level operation, a Ra-Be neutron source will be kept in the assembly. It will be located in the 1" re-entrant thimble, mentioned above, about 3" from the bottom of the fuel cylinder. It can be removed in "source jerk" tests during the initial approach to criticality.

It is estimated that about 800 grams will be required to produce criticality. This amount will be added stepwise, in progressively smaller quantities, during the approach to criticality. Careful measurement of multiplication will, of course, be made after each incremental addition. The first charge will be on the order of 200 grams, with enough diluting water to "cover" the source (3" from bottom of 11" cylinder). Thereafter, the U235 increments will be added, each with sufficient dilution to bring the reactor solution to operating level when the total required quantity of U235 has been added. One of the two boron rods will be cocked in safety position, the other will be in "down" position, during each incremental addition. A likely schedule of additions might be: IncrementsTotal U2351. 200 grams 200 grams2. 200 grams 400 grams3. 100 grams 500 grams

Increments (continued) Total U2354. 100 grams 600 grams5. 50 grams 650 grams6. 50 grams 700 grams7. 25 grams725 grams8. 25 grams 750 grams9.} ~800 grams.} small.} amountsN

 B. Operation at Higher Power

After the reactor has been brought to critical and has been operated for some time at low power levels, during which various measurements of reactor characteristics have been determined, addi- tional fuel will be added and the power level raised. The first three instruments mentioned above will no longer be needed, but the others listed will remain as a portion of the permanent equipment. In addition, two more channels will be added, and chief reliance for safety will be placed on these: 8. B-10 lined graphite ion-chamber, feeding into a linear amplifier equipped with trip mechanism for excessive neutron levels, and thence into a recorder. 9. B-10 lined graphite ion-chamber, feeding into a linear amplifier equipped with a trip mechanism for excessive neutron levels, and thence the output is bucked against a potentiometer selected voltage which corresponds to the desired level of reactor operation. The difference between the outputs of amplifier and potentiometer, if any, is fed to another amplifier and then to a reversible motor which drives the control rod in or out so as to minimize the difference. This then provides a mechanism by which the

level of operation of the reactor may be automatically controlled.

In addition to the safety trips on each of the two linear amplifiers, another safety trip is provided between the two amplifiers. That is, these two channels have identical equipment and are symetrically placed in the reactor assembly. The reading from the two, therefore, should be similar. If there is a significant difference, it indicates that one channel is defective. Operation of the safety trip, when the difference between the two channels exceeds a predetermined value, provides positive information to the operator that one circuit or the other is defective.

It is intended that all of the 6 channels described above shall be available during operation of the reactor at higher power levels. It is considered, however, that this number could be reduced without reducing the safety of operation. The minimum number required for operation of the reactor at any time will be set by policy decision of the Operating Staff after operating experience has been gained.

For use in bringing the reactor up to power after shutdown, one instrument will be available f or ascertaining that an adequate level of radiation is present before the control and safety rods are with drawn. That is, there must be enough radiation present, either from a neutron source, or from residual activity accumulated from prior operation of the reactor, to insure that the reactor activity will "follow" the withdrawal of the rods.

Before the reactor is brought to criticality, at least two men experienced in reactor design and operation, and not connected with the North Carolina State College project, will be brought to Raleigh to review the plan of operation and the instrument scheme provided.

Their approval will be obtained before the reactor is operated.

C. Health Safety from Reactor Radiation

The radiation hazards involved in each proposed experiment involving use of the reactor will be reviewed by the Operating Staff in advance. Approval by the reviewing group must be obtained before the experiment may be performed.

The Operating Staff will include the Director of the Reactor Project, or his designated representative, the Official Health Physicist, and at least one other person appointed by the Director.

Each person participating in a reactor experiment, or present during an experiment, will be required to wear a film badge and a radiation measuring pocket dosimeter.

The level of radiation in the Reactor Room, in various parts or the Reactor Building, in the ventilation air leaving the building, in the laboratory wastes, and at selected locations on the campus, will be continuously measured.

It shall be the policy to maintain on the reactor staff at all times at least one person trained in the knowledge of radiation hazards and protection and aware of the techniques and practices in this field as these are carried out at A.E.C. facilities. It shall be the intention to carry out practices in radiation safety which are consistent with safety practices at facilities of the A.E.C. (For example, two present members of the reactor staff are former A.E.C. Radiological fellows who, after completion of their training, were engaged for a considerable period as regular members of the B.N.L. Health Physics Group).

D. Health Safety from Radioisotopes

North Carolina State College has received from the Isotopes Division of the A.E.C. blanket authorization to purchase and use

isotopes produced by the A.E.C. This authorization is issued with the understanding that a local Radioisotope Committee, composed of State College staff members, will review and approve in advance all proposed uses of radioisotopes and will monitor the subsequent use by periodic inspection. This blanket authorization does not include use of radioisotopes in human beings or in widespread "field" experiments.

It is proposed that this blanket authorization, and the specifi- cations and mechanics of its operation, be extended to include iso- topes produced in the Raleigh Research Reactor. That is, the manipulations and uses of radioisotopes produced in the reactor, after their removal from the reactor and release by the Reactor Staff, would be subject to the same rules and regulations as are isotopes from A.E.C. facilities.

Miscellaneous A. Copyrights, Patents

As was presented as a portion of the original basis of estab- lishment of the reactor project at North Carolina State College, it is proposed that rights and title to published articles, textbooks, patents, etc., produced in or arising from the reactor project at North Carolina State College, be retained by the originating members of the reactor staff, under such rules of North Carolina State College as may pertain thereto.

B. Cost of Excessive Demands

Great effort has been exerted toward designing and constructing a reactor facility and devising procedures for its use having in- herent features adequate to provide for the security of the fission able fuel and the safety of personnel. Plans are being laid to

institute and maintain adequate records of operations, etc. It is anticipated that no difficulty will be encountered in arriving at details of operation and procedure in these various areas which are mutually acceptable to the A.E.C. and to North Carolina State College. If, however, it should develop that the A.E.C. requires certain operations, equipment, records, or procedures over and beyond what appears to State College to be reasonable and necessary for safe and efficient operation of the reactor, such that added burden and expense is incurred, then it is proposed that the costs involved be borne by the A.E.C. (For example, if extensive statistics on oper- ation, requiring lengthy reviews of the records, should be requested, an extra clerical assistant might be needed; or, if, in addition to the extensive system of locks and built-in security devices, it is deemed necessary to have a full-time system of guards protect the fuel from theft, this would be considerably beyond operating provi- sions which have been made by the College.

C. Disposal of Radioactive Wastes

Provision will be made to store short-lived radioactive materials accumulated from reactor operation until the activity has decayed to safe levels. However, no provisions have been made or planned for the disposal of long-lived isotopic wastes. It is proposed that an arrangement be made by the A.E.C. whereby these materials may be disposed of at Oak Ridge with a minimum of cost to the Raleigh Pro- ject. Agreement would be reached between State College and Oak Ridge on optimum routine procedures which could be followed.

It is further proposed that arrangement be made whereby waste materials (gloves, kleenex, etc.) contaminated with enriched Uranium could be processed at Oak Ridge, where feasible, for recovery of the U235; likewise whereby chemical and isotopic analyses on Uranium

samples, where necessary, could be performed at Oak Ridge at minimum cost to the Raleigh Project.