[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
RE: Nuclear-powered spacecraft plan feared
John, et al.,
I believe the event to which you refer was Cosmos 954, a Be-moderated
fission reactor fueled with HEU-Mo alloy (100 kWt; 10 kWe) (see
http://gamma.gsc.nrcan.gc.ca/images/cosmos.jpg). Cosmos 954 reentered
the earth's atmosphere on January 24, 1978 (I remember this fairly well)
on a trajectory that passed over the Northwest Territories, starting
over the Great Slave Lake and proceeding east-northeast (see
http://gamma.gsc.nrcan.gc.ca/images/mlorbit.gif for final orbits.) A
map of the approximately 600 km long debris field is shown on
http://gamma.gsc.nrcan.gc.ca/images/mlpath.gif.
Response to the reentry was a joint Canadian-US operation (Operation
Morning Light). US response assets included a couple of Nuclear
Emergency Search Teams (from then ERDA). This was a rather unpleasant
operation, since it involved debris mapping and recovery in some rather
nasty weather (-40 on either scale - see
http://gamma.gsc.nrcan.gc.ca/images/rec3.gif). Keeping radiation
monitoring equipment operating in such extreme temperatures proved to be
a significant challenge.
More than 50 large fragments including bits of steel and Be plates and
rods with near-contact dose rates ranging from 0.006 to 2 Gy/h were
subsequently recovered. The highest measured near-contact dose rate was
5 Gy/h. Approximately 65 kg of debris, a very small fraction of the
several ton mass of Cosmos 954, was recovered. Fuel particles (0.1-1 mm
diameter) ranging from 200-5000 MBq in activity were recovered. Dose
rates measured at 1 meter ranged from 0.1 - 1 mGy/h. Approximately 4000
fuel particles were recovered, representing approximately 0.1% of the
particles estimated to be dispersed from the reentry.
High altitude air sampling measure measurements revealed the presence of
enriched uranium at an altitude of approximately 40 km at 65 degrees
north between June and September 1978.
There's a write-up on the LLNL web site (see
http://www.llnl.gov/timeline/1970s/pdfs/1978.pdf) I also recall
perusing a beautiful color publication by ERDA that showed how NEST
reconfigured its equipment for arctic operations, as well as photographs
of some of the larger debris fragments. Alas, I do not have a copy of
that one.
There's also a brief entry on a DND/Canada Forces web site (see
http://www.dnd.ca/site/fourth_dimension/2002/jan02/jan25_fd_e.htm) and a
PDF bilingual reprint from "The Maple Leaf" on
http://www.dnd.ca/site/community/mapleleaf/vol_5/vol5_03/vol5-03pg14-15.
pdf.
Also see "Emergency Preparedness for Nuclear Powered Satellites", OECD
1990, which summarizes the following 6 malfunctions/reentries:
- Transit 5BN-3 (SNAP-9A RTG), 1964
- Nimbus B-1 (SNAP-19 RTG), 1968
- Apollo 13 (SNAP-21 RTG), 1970
- Cosmos 954 (nuclear reactor), 1978
- Cosmos 1402 (nuclear reactor), 1983
- Cosmos 1900 (nuclear reactor), 1988
The SNAP-9A was designed to vaporize on reentry and dispersed 630 TBq of
Pu-238 into the atmosphere at 120 km altitude. The SNAP-19A was
recovered from the Santa Barbara Channel and the Pu-238 microspheres
were subsequently reused. The RTG-21 from the aborted Apollo 13 mission
was designed to survive reentry and is lying at a depth of 6000m in the
Tonga Trench.
I hope this contributes to the thread. Obviously, the RTGs used for the
Galileo and Cassini deep space probes have substantially larger
inventories of Pu-238
George J. Vargo, Ph.D., CHP
vargo@physicist.net
610-925-1954
610-925-5545 (fax)
-----Original Message-----
From: owner-radsafe@list.vanderbilt.edu
[mailto:owner-radsafe@list.vanderbilt.edu] On Behalf Of John Johnson
Sent: Thursday, February 06, 2003 7:55 PM
To: Franz Schoenhofer
Cc: Radsafe (E-mail)
Subject: Re: Nuclear-powered spacecraft plan feared
Franz
If its the one I remember, it occurred in the seventies. The Pu was
Pu-238 and it was spread over a large area in the NW Territories. RP
staff from AECL/CRNL were sent to monitor the levels and only found a
slight increase in the total Pu levels, most of which was PU-239 from
fallout. _______________________ John R Johnson, PhD
idias@interchange.ubc.ca
----- Original Message -----
From: "Franz Schoenhofer" <franz.schoenhofer@CHELLO.AT>
To: "Grimm, Lawrence" <LGrimm@FACNET.UCLA.EDU>; "Radsafe (E-mail)"
<radsafe@list.vanderbilt.edu>
Sent: Thursday, February 06, 2003 2:03 PM
Subject: AW: Nuclear-powered spacecraft plan feared
-----Ursprüngliche Nachricht-----
Von: owner-radsafe@list.vanderbilt.edu
[mailto:owner-radsafe@list.vanderbilt.edu] Im Auftrag von Grimm,
Lawrence
Gesendet: Donnerstag, 06. Februar 2003 19:34
An: Radsafe (E-mail)
Betreff: RE: Nuclear-powered spacecraft plan feared
Radsafers:
A radsafer sent me the following (slightly edited), and my response to
him follows. I am seeking your comments/advice on the assumptions I am
making regarding a Pu accident.
--------------------------------------------------------------------
Lawrence and Radsafers,
I would like to remind all of you, that some decades ago, a satellite
with a Pu-238 battery on board was vaporized on its reentry into the
atmosphere. So this could be a good hint to the "hazards" of plutonium
batteries from spacecrafts or satellites. Unfortunately I do not have
any literature at hand, but I think, that some RADSAFErs will remember
this event. One consequence is for sure: In spite of the Pu distributed
mankind has not been exterminated!
Best regards,
Franz
************************************************************************
You are currently subscribed to the Radsafe mailing list. To
unsubscribe, send an e-mail to Majordomo@list.vanderbilt.edu Put the
text "unsubscribe radsafe" (no quote marks) in the body of the e-mail,
with no subject line. You can view the Radsafe archives at
http://www.vanderbilt.edu/radsafe/
************************************************************************
You are currently subscribed to the Radsafe mailing list. To
unsubscribe, send an e-mail to Majordomo@list.vanderbilt.edu Put the
text "unsubscribe radsafe" (no quote marks) in the body of the e-mail,
with no subject line. You can view the Radsafe archives at
http://www.vanderbilt.edu/radsafe/
************************************************************************
You are currently subscribed to the Radsafe mailing list. To unsubscribe,
send an e-mail to Majordomo@list.vanderbilt.edu Put the text "unsubscribe
radsafe" (no quote marks) in the body of the e-mail, with no subject line.
You can view the Radsafe archives at http://www.vanderbilt.edu/radsafe/