Management of Commercially Generated Radioactive Waste - U.S. ...

Response
requests.
95
CONSEQUENCE ANALYSIS
References at the end of final Section 5.5 contain the information the commenter
Draft Appendix I
Issue
Just as it is improper to neglect population dose in the river, it is improper to
neglect individual dose to users of groundwater. This is completely omitted in this sec-
tion. Since the ground water velocity is stated to be equal to one foot per day, or a lit-
tle over 100 meters per year, the aquifer would be expected to be a good water provider and
comparable to the aquifer of draft Appendix F which is stated as supporting "numerous shal-
low wells supplying residences and farms" and also a "public water supply well" for a city.
Population dose from use of the aquifer may very well be significant in addition to indivi-
dual doses. (113-EPA)
Response
An additional case involving a well intersecting a contaminated aquifer has been added
(see Section 5.5).
Draft Appendix I
Issue
We believe the comprehensive model used in the safety analysis is not applicable on a
generic basis. The modeling efforts of H. C. Burkholder and his colleagues at Battelle are
pioneering and commendable. However, in Appendix I the assumptions used in the model anal-
ysis are clearly spelled out on page 1.9. Among these assumptions are a) that "the repos-
itory is located in a non-salt formation surrounded by a geology with nuclide retention
properties similar to those for a particular Hanford Reservation subsoil"; and b) "the
groundwater flows into a surface stream with a flow rate of 10,000 ft 3 /sec (1/10 the flow
rate of the Columbia River near the Hanford Reservation) where the nuclides are further
diluted." This flow is equivalent to the average flow of the Delaware River at Trenton.
With these and other simplifying assumptions, the model predicts a benign outcome. However,
the problems are multiple.
First, although dilution of the radionuclide-bearing groundwater by a 10,000 ft 3 /sec
river is one plausible scenario for radwaste dissolved in Hanford ground waters, a 10,000-
fold concentration might occur in other environments, for example, in areas where ground-
water flow is toward marshes or wet playas. Second, what is the dose to man if the
groundwater were tapped by a future town well-field upgradient from discharge into the
river? Third, the Kd values for Hanford subsoil are unlikely to be applicable to fractured
media.