Introduction to Health Physics: Fourth Edition - Ruang Baca FMIPA UB

INTERNAL RADIATION SAFETY 631
treatment and disposition is determined by public opinion and by technical and
engineering considerations.
m Problems
11.1. A health physicist finds that a radiochemist was inhaling Ba35SO4 particles that
were leaking out of a faulty glove box. The radiochemist had been inhaling
the dust, whose mean radioactivity concentration was 3.3 MBq/m3 (9 × 10−5 μCi/cm3 ), for a period of 2 hours. Using the ICRP three compartment lung
model, calculate the absorbed dose to the lung during the 13-week period and
during the 1-year period immediately following inhalation.
11.2. A tank, of volume 100 L, contained 85Kr gas at a pressure of 10.0 kg/cm2 . The
specific activity of the krypton is 20 Ci/g. The tank is in an unventilated storage
room, at a temperature of 27◦C, whose dimensions are 3 m × 3m× 2m.Asa
result of a very small leak, the gas leaked out until the pressure in the tank was
9.9 kg/cm2 . A man unknowingly then spent 1 hour in the storage room. Assume
the half-saturation time for krypton solution in the body fluids to be 3 minutes.
Henry’s law constant for Kr in water at body temperature is 2.13 × 107 . Calculate
(a) the immersion dose, (b) the internal dose due to the inhaled krypton. The
partition ratio of Kr in water to Kr in fat is 1:10.
11.3. If the man in problem 2 turned on a small ventilation fan of capacity 100 ft3 /min
as he entered the room, calculate his immersion and inhalation doses.
11.4. An accidental discharge of 89Sr into a reservoir resulted in a contamination level
of 37 Bq (10−3 μCi) per mL of water.
(a) Using the basic radiological health criterion of the ICRP, would this water
be acceptable for drinking purposes for the general public if the turnover
half-time of the water in the reservoir is 30 days?
(b) If the water were ingested continuously; what maximum body burden would
be reached?
(c) How long after the start of ingestion would this maximum occur?
(d) What would be the absorbed dose during the first 13 weeks of ingestion?
(e) What would be the absorbed dose during the first year?
(f) What would be the absorbed dose during 50 years following the start of
ingestion?
11.5. Nickel carbonyl Ni(CO)4 has a maximum permissible atmospheric concentration
of 1 part per billion (ppb) based on its chemical toxicity. A chemist is going to use
this compound tagged with 63Ni. The specific activity of the nickel is 2.5 × 108 Bq/g (6.75 mCi/g). The industrial hygienist is planning to limit the atmospheric
concentration of Ni(CO)4 in the laboratory to 0.5 ppb. Will this restriction meet
the requirement for the radioactivity DAC of 3 × 10−3 μCi/mL?
11.6. Chlorine-36-tagged chloroform, CHCl3, whose specific activity is 100 μCi/mol,
is to be used under such conditions that 100 mg/h may be lost by evaporation.