The Effects of Atomic Radiation on Oceanography and Fisheries (1957) / Chapter Skim
Currently Skimming:
DISPOSAL OF RADIOACTIVE WASTES IN THE OCEAN: THE FISSION PRODUCT SPECTRUM IN THE SEA AS A FUNCTION OF TIME AND MIXING CHARACTERISTICS
DISPOSAL OF RADIOACTIVE WASTES IN THE OCEAN: THE FISSION PRODUCT SPECTRUM IN THE SEA AS A FUNCTION OF TIME AND MIXING CHARACTERISTICS
Pages 34-42
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 34... ...
At 50 per cent efficiency, this is equivalent to a world nuclear power consumption of 1.2x1010 mwh/yr. If this latter figure represents 10 per cent of the total world energy utilization, we are then assuming a world consumption of 1.2x1011 mwh/yr, which seems not unreasonable as an estimate for the year 2000 A
|
From page 35... ...
However the decay constants are very large for the first members of a chain, and thus one can neglect the exponential terms and assume a fission yield which is the total yield of the isotope under consideration plus all preceding members of the chain, for all irradiation times with which we shall be concerned. The experimental fission yield figures generally refer to the total chain yield, but because of the very low production of the later members of a chain by direct fission, there is no error involved in applying them to the first significantly long-lived chain member.
|
From page 36... ...
III. Fission product concentration in the sea as a function of linearly increasing fission rate We can get some idea of the transient characteristics of the fission product spectrum in the sea by examining the build-up of fission products with an increasing rate of fission.
|
From page 37... ...
IV. Steady state fission product spectrum in a homogeneous, rapidly mixed sea The first three columns of Table 1 list all the fission products of any significance, together with their half-lives and fission yields.
|
From page 38... ...
The fission products are listed in order of decreasing total activity in the sea, with radioactive daughters paired with their parents. The total amount of all fission products in the sea is found to be about 3200 metric tons, corresponding to almost one million megacuries of activity.
|
From page 39... ...
We wish to ask what steady-state activity per unit volume of water will be in the mixed layer, as a function of the rate of cross-thermocline exchange of sea water and fission products. The water balance between the reservoirs is given by: and from the expression for N' one sees that T, the average life, is also the time required for the original number of N0 particular molecules to be reduced to l/e times the initial number, r is thus formally equivalent to a radioactive mean life.
|
From page 40... ...
We call a the "oceanographic partition factor." It is a function of the mixing rate of the sea and the decay constant of the individual isotope, and is a measure of the effectiveness of the cross-thermocline exchange rate in buffering the mixed layer from the fission products introduced into the deep sea. Values of a are tabulated in column 6 of the table, and range from about 1 for the longest lived isotopes to about 250 for an isotope with a half-life of 8 days.
|
From page 41... ...
AVERAGE LIFE OF A WATER MOLECULE IN THE DEEP SEA TAKEN AS 300 YEARS; AVERAGE DEPTH OF THE MIXED LAYER TAKEN AS 100 METERS. Total amount in ocean Activity (dps/liter)
|
From page 42... ...
It should be noted that the figures given in the table for the predicted activities in the mixed layer refer only to cross-thermocline mixing by physical processes, exclusive of biological transfer through the thermocline. However, the figures listed provide a basis for speculation on the hazardous effects of the mixed layer activity, in that comparison may be made with biological concentration factors, discussed elsewhere in this report, to predict the activity levels in marine organisms.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.