is deposited annually, then the total Sr* on the ground and in the air above Milford Haven, due
to explosions since 1954, will be given very nearly by:
X= 6.9 +52
(6)
m
It follows that the mean rate of injection over the past three years will be given by X)
where:
Xp = %4 (6.9 + 2.3/2)
(7)
If this rate of injection continues, the ground level concentration at a time t years after
1954 will be given by:
Xp = 9 (1 — eM)
X
X
—
team U7e
a VtAm)t
™)
(8)
The equilibrium value of X, to be reached in about 100 years time will be:
Xy
dh
If
X,
_2.3+6.9 Am
At+AM
3x(A + Am)
m = 0.12, the equilibrium deposit of Sr®® derived from equation (9) is 290 mc/km/?.
Tne rate of deposition at a time t after the beginning of 1954 is given by the expression:
iagsetiaps ste
which rises to an equilibrium value of AmX)/(A + Am). If Am = 0.12, the equilibrium value of
7.2 mc/km?/year will be reached in about twenty years time.
It should perhaps be pointed out that this model is really only applicable to long-term extrapolation Since it is not consistent in detail with the observed pattern of deposition throughout
the years 1954-1957.
“ade
248