Table 6.11.1 Photon Dose Rates at 2 Meters from Cylinders of Plutonium Containing 1 kg

DOE-STD-1128-98

Guide of Good Practices for Occupational Radiological Protection in Plutonium Facilities

Figure 6.7 shows the reduction in dose equivalent rate for various shielding

materials for plutonium tetrafluoride sources, which have an average neutron

energy of 1.3 MeV. For practical purposes, the shielding thickness for glove

boxes is limited to about 4 in.; it is not possible to operate machinery through

thicker shields. Figure 6.8 shows the reduction in dose equivalent rate through

various slab shields for plutonium dioxide. These data were obtained from

measurements of the neutron dose using a TEPC.

Table 6.11.1

Photon Dose Rates at 2 Meters from Cylinders of Plutonium Containing 1 kg of

Plutonium at 5 Years After Chemical Separation

Photon Dose Rate, mrad/h

Shield

Thickness,

Shield

19% 240Pu Source

6% 240Pu Source

Material

1.74

19.3

Polyvinyl chloride

0.005

0.570

8.72

(PVC)

0.038

0.391

6.29

0.084

Lead glove

0.094

1.85

0.105

Heavy Lead glove

0.152

0.54

0.0464

Lucite

0.612

7.03

0.447

2.54

3.30

0.190

0.144

2.69

Steel

0.025

0.131

2.41

0.038

0.121

2.19

0.051

0.0418

0.42

0.317

0.0299

0.221

0.635

0.0205

0.134

1.33

0.0119

0.0766

2.43

0.0103

0.0701

Lead

0.635

0.00288

0.0380

1.27

0.000391

0.0156

2.57

0.000023

0.00429

5.08

0.0000001

0.000467

10.16

0.0251

0.135

X-ray glass

0.645

0.0144

0.0841

1.30

0.00534

0.0463

2.60

Lead apron

0.16

0.306

0.0346

Safety glass

1.30

1.94

0.109

2.60

1.50

0.0886

Adapted from NUREG/CR-5550 (Reilly et al., 1991)

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