Appendix A: Useful Numerical Values

DOE-HDBK-1129-99

APPENDIX A: USEFUL NUMERICAL VALUES

A.1 General Data

1 becquerel (Bq) = 1 disintegration/second = 2.7 x 10-11 Ci

1 Ci = 3.7 x 1010 disintegrations/second = 3.7 x 1010 Bq = 37 GBq

Avogadro's Number = 6.023 x 1023 molecules/mole

STP conditions: 760 Torr, and 0oC (1 atm and 273K)

1 mole of ideal gas at STP = 22.414 L at 0 C, and approximately 24.2 L/mole at room

temperature

1 Sievert (Sv) = 8.38 roentgens = 100 rem

A.2 General Tritium Data

Tritium decays to 3He + beta + neutrino

Half-life of tritium (Scientific purposes) = 12.323 0.004 years (4500.88 1.46 days)

Half-life of tritium (Accountability purposes) = 12.33 +/- 0.06 years (DOE M 474.1-2,

Figure IV-2)

Tritium decay factor = 0.99984601/day

Maximum beta energy of decay (E max.) = 18.6 keV

Mean beta energy of decay (E mean) = 5.69 keV

Volume of 1 Ci of tritium at STP = 0.386 mL

Tritium gas = 9619 Ci/g

T2 gas contains 58023 Ci/mole

2.589 Ci/cm3 of T2 at STP

Diameter of a tritium atom (approximate) = 1.1 Angstroms

Dissociation energy, T2 to 2T = 4.59 eV

Ionization energy, T to T+ + e- = 13.55 eV

Atomic weight = 3.01605

Gram molecular weight of tritium = 6.0321 g

Grams tritium/liter at STP = 0.269122 g/L

Liters/gram of tritium at STP = 3.71579 L/g

Boiling point of tritium at 1 atmosphere = 25.0 K

T2 gas, at 1 atmosphere pressure and 25oC = 2.372 Ci/cm3

Tritiated water, T2O = 3200 Ci/cm3

A.3 Regulatory Quantities

Type B Quantity = > 1080 Ci

Type A Quantity = > 0.108 to <1080 Ci depending on form

Limited Quantity = < 21.6 Ci of tritium in gaseous form

< 1.08 Ci of tritium in solid form

< 1 Ci of tritium at a concentration of > 1 Ci/L liquid

< 100 Ci at a concentration of > 0.1 to < 1 Ci/L liquid

< 1000 Ci at a concentration of < 0.1 Ci/L liquid

A2 Quantity = 40 TBq (1080 Ci)

Limited Quantity Excepted Package Requirement for tritium

- Radiation level < 0.005 mSv/hr (0.5 mrem/hr)

- Quantity of radioactive material < limit in 49 CFR 173.425

A-1