Appendix A - Values of Significant Physical, Chemical, Radiological Properties of HT, HT O, STCS

DOE-HDBK-1184-2004

APPENDIX A VALUES OF SIGNIFICANT PHYSICAL, CHEMICAL, AND RADIOLOGICAL

PROPERTIES OF HT, HT O, AND STCS

Physical/Chemical Properties

Atomic weight1 of a tritium atom

3.01605 g/mole

Diameter of a tritium atom (approximate) 1

1.1 Angstroms

Dissociation energy1, T2 to 2T

4.59 eV

Ionization energy1, T to T+ e-

13.55 eV

Gram molecular weight of tritium1 (T2)

6.0321 g

Density of tritium gas (T2) at STP1

0.269122 g/l

Boiling point of tritium (T2) at 1

25.0 K

atmosphere1

Physical/Radiological Properties

Half Life1

12.323 0.004 years

Biological Half Life

Approximately 10 days

Tritium decay factor1

0.99984601/day

Maximum beta energy of decay (Emax ) 1

18.6 keV

Mean beta energy of decay (Emean) 1

5.69 keV

Volume of 1 Ci of tritium at STP1

0.386 ml

Specific Activity of tritium gas (T2) 1

9619 Ci/g

Activity per mole, T2 gas1

58023 Ci/mole

Activity per volume of T2 at STP1

2589 Ci/l

Activity per volume at 1 ATM pressure and

2372 Ci/l

25oC1

Activity per volume of tritiated water1 (T2O)

3200 Ci/cm3

Range of Tritium Beta Particles (18.6 Kev):

Independent of density

0.59 mg/cm2

In Air1

0.45 cm

In Water1

0.0006 cm

In Tissue1

0.0007 cm

Dosimetric Properties

Thumb-rules for Dose Conversion

6 x 10-2 mrem CEDE/Ci

Dose from a single intake of HTO per

activity taken up by the body1

Dose from a single intake of HTO per

3 mrem CEDE/ Ci/l in urine

activity in urine1

4.3 x 10- 6 (rem/hr)/(Ci/ m3)

Effective dose rate from inhalation of HT