MEMORANDUM ON
OPERATING PLANS FOR THE
RALEIGH RESEARCH REACTOR

Clifford K. Beck
February 25, 1953

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

MEMORANDUM ON
OPERATING PLANS FOR THE
RALEIGH RESEARCH REACTOR

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.

"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:

Increments	Total U235
1. 200 grams	200 grams
2. 200 grams	400 grams
3. 100 grams	500 grams

Increments (continued)	Total U235
4. 100 grams	600 grams
5. 50 grams	650 grams
6. 50 grams	700 grams
7. 25 grams	725 grams
8. 25 grams	750 grams
9.}	~800 grams
.} small
.} amounts
N

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.

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).

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.

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.

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.

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.