Table 7-1. Site Boundary Doses Associated with Release

DOE-HDBK-3010-94

7.0 Application Examples; Introductory Material

boundary distance for the mock operation is 2 km, and any respirable release would be

anticipated to be an oxide by the time it traversed such a distance through air.

The dose measures used in the calculation are as presented in Table 7-1 below. At 2 km, the

values of y and z are ~ 63 and 19 respectively for limiting F at 1 m/sec windspeed

conditions, and a conservative breathing rate is 3.3E-4 m3/sec. Using these values indicates,

for example, that a source term of 0.9 Ci of Pu-239, or ~ 14.5 g, produces a dose of 25

rem to a maximally exposed person at the site boundary (i.e., individual there for duration of

plume passage with no protection). Use of one of the Gaussian plume model computer codes

currently in use in the DOE complex provided an estimate of 1 Ci release to obtain a dose of

25 rem, thus confirming the general appropriateness of the hand calculation. This code also

indicated that if particulate deposition was accounted for, using a typical velocity of 1 m/sec,

the release needed to achieve a 25 rem dose at the site boundary increased by a factor of 5.

Table 7-1 lists releases external to the building and their resulting site boundary doses in

terms of 50-year committed effective dose equivalent, both with and without deposition. If

building leakpath factors are taken into account, the initial source term producing these

releases would be orders of magnitude greater if airflow passed through HEPA filtration.

Even if ventilation fails and the building is in a relatively undamaged static condition, it

would not be unusual for the required initial source term for a given site boundary dose to be

at least an order of magnitude greater due to building deposition alone. The examples in this

handbook provide initial source terms at the point of generation only, which would equate to

the values in Table 7-1 for a completely unmitigated case.

Table 7-1. Site Boundary Doses Associated with Release

Case

100 rem

25 rem

5 rem

1 rem

1. No deposition

3.6 Ci

0.9 Ci

0.2 Ci

0.04 Ci

(58 g)

(14.5 g)

(2.9 g)

(0.6 g)

2. Deposition

18 Ci

4.5 Ci

0.9 Ci

0.2 Ci

(290 g)

(73 g)

(14.5 g)

(2.9 g)

As noted in the discussion of release models, neither set of values in Table 7-1 is inherently

meaningful. Each merely provides a perspective that may be useful under certain

circumstances. Either model is only as good as the decisions it leads to. If a model leads to

obviously inappropriate conclusions or actions, there is no reason to accord the model any

credence. This point is further amplified by the examples.

Page 7-4