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Title: SUMMARY REPORT OF REACTOR HAZARDS FOR THE PROTOTYPE PHYSICAL CONSTANTS TESTING REACTOR

Abstract

ABS>The safety aspects of the design and operation of the Prototype Physical Constants Testing Reactor (PCTR) are discussed in some detail. This reactor is essentially a seven-foot cube of graphite with a large hole at its center, about 2' x 2' x 3'. It is made critical with uranium enriched to at least 92 per cent in U/sup 235/ and runs normally at a power of about one watt. Sections of various graphite-U lattices are inserted into the large hole at the center of the reactor, and the effects of these test lattices on the reactivity of the PCTR are noted. There are two mechanical safety systems on the reactor; eight shutter-type control rods, which are driven to the closed position by springs in about 0.25 seconds, and four cadmium disks which fall freely into the reactor under the force of gravity in about 0.5 seconds. These 12 mechanical safeties have individual driving and electromagnetic release mechanisms. The electromagnets are controlled by flux monitoring through five electronic channels, two of which are proportional counter channels for subcritical and postcritical monitoring, while the remaining three are ion chamber channels for post-critical and level monitoring. U all of these mechanical devices fail,more » the hollow fuel elements in the driver rods will melt and collapse causing an increase in self-shielding of the U/sup 235/. When this occurs, the reactor will lose about six per cent in DELTA k/k. The collapsing of fuel elements occurs quickly enough to shut down the reactor before the fuel vaporizes, after the instantaneous introduction of anything less than three per cent DELTA k/k. Finally, if an excursion continues until the fuel elements in the driver rods vaporize, short-lived fission products from about 3 x 10/sup 17/ fissions will be released to the atmosphere. An analysis of the distribution of these fission products indicates that little damage is to be expected outside the area in which the reactor is located. (auth)« less

Authors:
; ; ;
Publication Date:
Research Org.:
General Electric Co. Hanford Atomic Products Operation, Richland, Wash.
OSTI Identifier:
4332124
Report Number(s):
HW-32791
NSA Number:
NSA-12-001020
DOE Contract Number:  
W-31-109-ENG-52
Resource Type:
Technical Report
Resource Relation:
Other Information: Decl. Apr. 4, 1957. Orig. Receipt Date: 31-DEC-58
Country of Publication:
United States
Language:
English
Subject:
PHYSICS; ACCIDENTS; CONFIGURATION; CONTROL ELEMENTS; CONTROL SYSTEMS; CRITICALITY; ENRICHMENT; GRAPHITE; GRAPHITE MODERATOR; IRRADIATION; MATERIALS TESTING; MEASURED VALUES; OPERATION; PCTR; PLANNING; REACTIVITY; REACTOR CORE; REACTOR SAFETY; REACTORS; RODS; SHUTDOWN; STANDARDS; STARTUP; URANIUM; URANIUM 235; VARIATIONS; ZONES

Citation Formats

Donahue, D J, Lanning, D D, Horning, W A, and Dickeman, R L. SUMMARY REPORT OF REACTOR HAZARDS FOR THE PROTOTYPE PHYSICAL CONSTANTS TESTING REACTOR. United States: N. p., 1954. Web.
Donahue, D J, Lanning, D D, Horning, W A, & Dickeman, R L. SUMMARY REPORT OF REACTOR HAZARDS FOR THE PROTOTYPE PHYSICAL CONSTANTS TESTING REACTOR. United States.
Donahue, D J, Lanning, D D, Horning, W A, and Dickeman, R L. Thu . "SUMMARY REPORT OF REACTOR HAZARDS FOR THE PROTOTYPE PHYSICAL CONSTANTS TESTING REACTOR". United States.
@article{osti_4332124,
title = {SUMMARY REPORT OF REACTOR HAZARDS FOR THE PROTOTYPE PHYSICAL CONSTANTS TESTING REACTOR},
author = {Donahue, D J and Lanning, D D and Horning, W A and Dickeman, R L},
abstractNote = {ABS>The safety aspects of the design and operation of the Prototype Physical Constants Testing Reactor (PCTR) are discussed in some detail. This reactor is essentially a seven-foot cube of graphite with a large hole at its center, about 2' x 2' x 3'. It is made critical with uranium enriched to at least 92 per cent in U/sup 235/ and runs normally at a power of about one watt. Sections of various graphite-U lattices are inserted into the large hole at the center of the reactor, and the effects of these test lattices on the reactivity of the PCTR are noted. There are two mechanical safety systems on the reactor; eight shutter-type control rods, which are driven to the closed position by springs in about 0.25 seconds, and four cadmium disks which fall freely into the reactor under the force of gravity in about 0.5 seconds. These 12 mechanical safeties have individual driving and electromagnetic release mechanisms. The electromagnets are controlled by flux monitoring through five electronic channels, two of which are proportional counter channels for subcritical and postcritical monitoring, while the remaining three are ion chamber channels for post-critical and level monitoring. U all of these mechanical devices fail, the hollow fuel elements in the driver rods will melt and collapse causing an increase in self-shielding of the U/sup 235/. When this occurs, the reactor will lose about six per cent in DELTA k/k. The collapsing of fuel elements occurs quickly enough to shut down the reactor before the fuel vaporizes, after the instantaneous introduction of anything less than three per cent DELTA k/k. Finally, if an excursion continues until the fuel elements in the driver rods vaporize, short-lived fission products from about 3 x 10/sup 17/ fissions will be released to the atmosphere. An analysis of the distribution of these fission products indicates that little damage is to be expected outside the area in which the reactor is located. (auth)},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1954},
month = {9}
}

Technical Report:
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