Document Details


Title:
OPERATION GREENHOUSE, ANNEX 62 - THE EFFECT OF THERMAL RADIATION ON MATERIAL - SCIENTIFIC DIRECTOR'S REPORT OF ATOMIC WEAPONS TESTS AT ENIWETOK, 1951
Author(s):
BROIDO, A [UNITED STATES NAVAL RADIOLOGICAL DEFENSE LABORATORY]; BUTLER, C P [UNITED STATES NAVAL RADIOLOGICAL DEFENSE LABORATORY]; GUTHRIE, A [UNITED STATES NAVAL RADIOLOGICAL DEFENSE LABORATORY]; WILLOUGHBY, A B [UNITED STATES NAVAL RADIOLOGICAL DEFENSE LABORATORY]; MCGREEVY, J M [UNITED STATES NAVAL RADIOLOGICAL DEFENSE LABORATORY]; MONAHAN, T I [UNITED STATES NAVAL RADIOLOGICAL DEFENSE LABORATORY]; DAVIS, G E; BANET, L; JEHLE, E J
Subject Terms:
THERMAL RADIATION; RADIATION EFFECTS; MATERIALS; GREENHOUSE OPERATION; MEASURING METHODS; TESTING
Document Location:
Location - NNSA/NSO Nuclear Testing Archive Address - P.O. Box 98521 City - Las Vegas State - NV Zip - 89193-8521 Phone - (702)794-5106 Fax - (702)862-4240 Email - CIC@NV.DOE.GOV
Document Type:
REPORT
Publication Date:
1951 Sep 30
Declassification Status:
Declassified
Document Pages:
0266
Accession Number:
NV0051299
Document Number(s):
WT70
Originating Research Org.:
UNITED STATES NAVAL RADIOLOGICAL DEFENSE LABORATOR
OpenNet Entry Date:
1994 Aug 26
Description/Abstract:
PROJECT 6.2 WAS SET UP PARTLY TO OBTAIN INFORMATION CONCERNING THE CHA RACTERISTICS OF THERMAL RADIATION FROM AN ATOMIC BOMB DETONATION NECES SARY TO THE PROSECUTION OF THE GENERAL LABORATORY THERMAL PROGRAM AND PARTLY TO MAKE EXPOSURES OF MATERIALS WHICH COULD NOT BE DONE IN THE L ABORATORY. THE THERMAL-RADIATION CHARACTERISTICS OF GREATEST INTEREST WERE THE TOTAL ENERGY, THE TIME-INTENSITY RELATION, AND THE SPECTRAL D ISTRIBUTION. MEASUREMENTS OF THESE CHARACTERISTICS WERE MADE AT SEVERA L DISTANCES USING CALORIMETERS WITH OSCILLOGRAPHIC RECORDERS, ROTATING DRUMS WITH SENSITIVE-PAPER INDICATORS, AND PASSIVE RECEIVERS CONSISTI NG OF METAL FOILS. A NUMBER OF THE MATERIALS USED IN THE FIELD WERE PR EVIOUSLY EXPOSED TO LABORATORY SOURCES. THOSE MATERIALS USED IN THE IN CENDIARY PROGRAM WERE CHOSEN FOR STUDIES OF THE EFFECTS OF SUCH FACTOR S AS AREA, BACKING MATERIAL, GEOMETRY, AND REFLECTANCE ON THE INCENDIA RY CHARACTERISTICS. DOCUMENTATION WAS CARRIED OUT BY MEANS OF MOTION-P ICTURE PHOTOGRAPHY. THE TOTAL THERMAL-ENERGY VALUES AT APPROXIMATELY 2 MILES FROM GROUND ZERO WERE FOUND TO BE ABOUT ONE-HALF OF THOSE EXPEC TED. THE VALUES AT THE CLOSER STATIONS WERE FOUND TO BE EVEN SMALLER F RACTIONS OF EXPECTED VALUES. TIME-INTENSITY CURVES INDICATE THAT THIS FURTHER REDUCTION IS DUE TO OBSCURING MATERIAL ARISING AT ABOUT 0.5 SE C BETWEEN GROUND ZERO AND THE POINTS AT WHICH MEASUREMENTS WERE MADE. PEAK INTENSITIES WERE REACHED IN APPROXIMATELY 0.25 SEC, AND IT IS PRO BABLE THAT MOST THERMAL DAMAGE OCCURRED WITHIN 1 SEC. SINCE THE SHAPE OF THE THERMAL PULSE WAS DIFFERENT FOR EACH STATION, IT WAS NECESSARY TO MAKE TIME CORRECTIONS IN THE ANALYSIS OF THE PASSIVE-RECEIVER DATA. ROUGH SPECTRAL MEASUREMENTS INDICATED THAT THE BULK OF THE THERMAL RA DIATION WAS IN THE VISIBLE PORTION OF THE SPECTRUM, ALTHOUGH ALL MEASU REMENTS ARE UNCERTAIN TO 10 PER CENT OF THE TOTAL THERMAL ENERGY. WITH THIS UNCERTAINTY NO ULTRAVIOLET ENERGY WAS FOUND, AND THE INFRARED EN ERGY BEYOND 1 MICRO WAS MEASURED TO BE ONLY 10 PER CENT. ON THE BASIS OF THESE RESULTS, ALL EXISTING LABORATORY SOURCES WOULD APPEAR TO OVER EMPHASIZE THE INFRARED PORTION OF THE SPECTRUM. A CONSIDERABLE AMOUNT OF DATA WAS OBTAINED CONCERNING THE EFFECT OF THE FIELD RADIATION ON M ATERIALS PREVIOUSLY EXPOSED TO LABORATORY SOURCES. A COMPARISON OF FIE LD AND LABORATORY EFFECTS UNDER SIMILAR CONDITIONS OF EXPOSURE WILL PR OVIDE AN INDICATION OF THE EXTENT TO WHICH THE LABORATORY SOURCES SIMU LATE THE FIELD SOURCE. THE RESULTS OF THE INCENDIARY EXPERIMENTS SHOWE D THAT SMALL INDIVIDUAL SAMPLES OF SOLID COMBUSTIBLE MATERIALS SUCH AS WOOD AND CLOTH DID NOT SUSTAIN FIRES FOR MORE THAN 1 SEC OR SO. FOR T HE STATIONS USED, NO FIRES EXISTED AT THE TIME OF ARRIVAL OF THE BLAST WAVE. HOWEVER, INDICATIONS ARE THAT THE PROPER COMBINATION OF MATERIA LS ARRANGED IN SUITABLE GEOMETRY MAY RESULT IN SUSTAINING PRIMARY FIRE S. THE NATURE OF THE RESULTS OBTAINED, PARTICULARLY THE EFFECT OF OBSC URING MATERIAL, INDICATES THE NEED FOR ADDITIONAL INFORMATION FROM FUT URE ATOMIC-BOMB-DETONATION FIELD TESTS. IN PARTICULAR, IT IS CONSIDERE D HIGHLY DESIRABLE TO OBTAIN INFORMATION FROM SEVERAL SIZES OF DETONAT IONS AND FOR AIR BURSTS.


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