Table 3-1. Fractional Airborne Releases During the <a href="http://armytransportation.tpub.com/TM-55-203/Chapter-11-Heating-151.htm">Heating</a> with Flowing Air of Concentrated Plutonium Nitrate Solution

DOE-HDBK-3010-94

3.0 Liquids; Aqueous Solutions

Table 3-1. Fractional Airborne Releases During the Heating with

Flowing Air of Concentrated Plutonium Nitrate Solution

(Table 1 from M ishim a, Schwendim an, and Radasch,

Novem ber 1968)

Air Velocity, m /s

Sam pling Tim e, hr

Tem p, C

ARF

1.0

1.3E-7

0.5

<1.0E-8

0.5

5.3E-7

1.0

1.5

5.7E-7

100

0.1

1.0E-5

100

0.5

3.0E-5

the study reference document (reproduced as Table A.1 in Appendix A) and shows the ARFs

from evaporation of concentrated plutonium nitrate solutions under three air velocities (0.1,

0.5, and 1.0 m/s).

A schematic diagram of the experimental apparatus is shown in Figure A.1 (Appendix A).

Approximately 2.5 to 3 ml of a concentrated Pu(NO3)4 solution containing from 0.72 to

0.86 g Pu were placed in a shallow depression (~25.4-mm diameter x ~2.4-mm deep) in a

31.8-mm diameter x 6.35-mm deep stainless steel dish. The dish was placed in a teflon

retainer that filled half of the diameter of a 38.1-mm diameter borosilicate glass tube.

Filtered room air was drawn through the tube at three nominal velocities (0.1, 0.5, and

1.0 m/s) over the solution and through a water-cooled condenser to remove excess moisture;

the airborne particles were then collected on an in-line glass fiber filter. The liquids were

heated to various temperatures by heat lamps positioned over the liquid. The evaporation

times ranged from 1.5 to 24 hours. None of the solutions were observed to boil during any

of the experiments and the airborne release is most probably due to the aerodynamic breakup

of the surface, with release increasing as temperature increases due to reduced surface

tension.

The airborne fractional releases measured are shown in Table 3-1; ARFs range from <1E-8

to 3E-5. The highest ARFs were measured at the highest temperature (1E-5 and 3E-5 at

100 oC). The limited data also tend to indicate some increase in airborne release with

increasing air velocity. The surfaces during the drying were relatively undisturbed (no

visible surface disturbance). The upper bound release is 3E-5, and, in as much as the size

distribution of the airborne materials was not measured, a conservative value of 1.0 is

selected for the RF. The median value is 6E-7 (5.5E-7 rounded upward) with an average

value of 7E-6.

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