A METHOD FOR CALCULATING THE NEUTRON FLUX IN A SHUTDOWN REACTOR WITH A PHOTONEUTRON SOURCE

Journal Article · Mon Apr 01 04:00:00 EST 1963 · At. Energ. (USSR)

OSTI ID:4718800

Konstantinov, L V; Kochetov, B I

Subcritical neutron flux measurements in a shutdown reactor are rendered difficult by the radiation of the fission products; artificial neutron sources are used to increase the neutron flux to the level required by the instrumentation. In order to eliminate the expensive Po-Be sources the use of photoneutron sources containing Be or heavy water is considered, employing Na/sup 24/, Sb/sup 124/, etc. as the gamma source. The decay of the source after the shutdown of the reactor is compensated by its activation by thermal neutrons during the subsequent operation of the reactor. The negative reactivity thus introduced must be compensated by a ( gamma ,n) reaction. A method was developed for calculating photoneutron sources with a gamma source consisting of the fission fragments formed during the operation of the reactor. The method also allows the calculation of photoneutron sources using radioactive isotopes, taking the relative positions of the Be and gamma emitter into consideration. The neutron flux in the core is determined by solving the eigenfunctions of the reactor. From these the required reactor power level and Be concentration may be obtained. The validity of the formula was verified with the First Soviet Atomic Power Station. Before startup at the subcritical state DELTA k = 0.093 an 8 kg BeO rod was introduced in the central lattice, resulting in an increase of the flux by a factor of 2.3 to 2.5. The calculated and experimental values agreed with each other within 10%. (TTT)

• Research Organization: Originating Research Org. not identified
• NSA Number: NSA-17-026797
• OSTI ID: 4718800
• Journal Information: At. Energ. (USSR), Journal Name: At. Energ. (USSR) Vol. Vol: 14
• Country of Publication: Country unknown/Code not available
• Language: Russian

Related Subjects

ACTIVATION
ANTIMONY 124
BERYLLIUM
BERYLLIUM OXIDES
CRITICALITY
DECAY
DIFFERENTIAL EQUATIONS
FISSION PRODUCTS
GAMMA RADIATION
GAMMA SOURCES
HEAVY WATER
INSTRUMENTS
NEUTRON FLUX
NEUTRON SOURCES
NEUTRONS
NUCLEAR REACTIONS
OPERATION
PHOTONEUTRONS
POLONIUM
RADIATIONS
RADIOISOTOPES
REACTIVITY
REACTOR CORE
REACTOR TECHNOLOGY
REACTORS
SHUTDOWN
SODIUM 24
STARTUP
THERMAL NEUTRONS