4 @ Containment: of Underground Nuclear Explosions
Containment Failures: Containment failures are unintentional releases of radioactive
material to the atmosphere dueto a failure of the
containment system. They are termed ‘‘ventings,’’ if they are prompt, massive releases; or
**seeps,”” if they are slow, small releases that
occur soonafter the test.
Late-Time Seeps: Late-time seeps are small
releases that occur days or weeksafter a test
when gases diffuse through pore spaces of the
overlying rock and are drawn to the surface by
decreases in atmospheric pressure.
Controlled Tunnel Purging: A controlled
tunnel purgingis an intentional release to allow
either recovery of experimental data and equipmentor reuse of part of the tunnel system.
Operational Release: Operational releases
are small, consequential releases that occur
when core or gas samples are collected, or when
the drill-back hole is sealed.
The containment record can be presented in
different ways depending on which categories of
releases are included. Reports of total numbers of releases are often incomplete because
they include only announcedtests or releases
due to containmentfailure. The upper portion
of table 1-1 includes every instance (for both
announced and unannouncedtests) where radio-
active material has reached the atmosphere
under any circumstances whatsoever since
the 1970 Baneberry test.
Table 1-1—Reieases From Underground Tests
(normalized to 12 hours after event*)
All releases 1971-1988:
Containment Failures:
Camphor, 19719 0. ccc cee 360 Ci
Diagonal Line, 1971 .............. ccs 6,800
Riola, 1980 2.0... cece eee 3,100
Agrini, 1984 260. ce eee 690
Late-time Seeps:
Kappeli, 1984 0. ec eee 12
Tierra, 1984 20. 600
Labquark, 1986 2000. eee 20
Bodie, 19867... eee 52
Controlled Tunne! Purgings:
Hybla Fair, 1974..0.......0....0 0. eee 500
Hybla Gold, 1977... 00.0. 0.005
Miners lron, 1980 ..........0. 0.00.0. 0.3
Huron Landing, 1982 .................2.....-0. 280
Mini Jade, 1983.00.00... 0. cee 1
Mill Yard, 1985.0... 0... eee 5.9
Diamond Beech,1985 ................. 0.002000 0 1.1
Misty Rain, 1985 ............... 0... 63
Mighty Oak, 1986.......................0005. 36,000
Mission Ghost, 1987¢ ..................0000 000005 3
Operational Releases:
108 tests from 1970-19887 ..........000.0.00000.. 5,500
Total since Baneberry: 54,000 Ci
Major pre-1971 releases:
Platte, 1962............0...0..0..000000. . 1,900,000 Ci
Eel, 1962... 0... cee 1,900,000
Des Moines, 1962 ...................... 11,000,000
Baneberry, 1970 ....................... 6,700,000
26 others from 1958-1970 ............... . 3,800,000
Other Releases for Reference
Total: 25,300,000 Ci
NTS Atmospheric Testing 1951-1963: .. 12,000.000.000 Ci
1 Kiloton Aboveground Explosion: .......
10,000,000
Chernobyl (estimate):........0..0...0.000.0. 81,000,000
8A+12 values apply only to containment failures, others are at time of
release.
oThe Campnhorfailure includes 140 Ci from tunnel purging
°Bodie and Mission Ghost also had dnili-back releases
CMany of these operational releases are associated with tests that were not
announced.
SOURCE: Office of Technology Assessment, 1989
Since 1970, 126 tests have resulted in radioactive material reaching the atmosphere with a
by pre-Baneberry undergroundtests (25,300,000
Ci), the early atmospheric tests at the Nevada
amount, 11,500 Ci were due to containment
failure and late-time seeps. The remaining
42,500 Ci were operational releases. and controlled tunnel purgings—with Mighty Oak (36,000
amount that would be released by a single
1-kiloton explosion conducted aboveground
(10,000,000 Ci).
total release of about 54,000 Curies (Ci). Ofthis
Ci) as the main source. The lower portion of the
table shows that the release of radioactive
material from underground nuclear testing since
Baneberry (54,000 Ci) is extremely small in
comparison to the amount of material released
Test Site (12,000,000,000 Ci), or even the
From the perspective of humanhealth risk:
If the same person hadbeenstanding at the
boundary of the Nevada Test Site in the area
of maximum concentration of radioactivity
for every test since Baneberry (1970), that