[A new evaporation procedure for monitoring of iodine-125 in liquid waste].
A simplified monitoring method of 125I in liquid waste was devised. The waste water of 200 cm3 was taken on a Saran (polyvinylidene chloride) film covering a stainless steel vat. A stable iodine (20 mg) and sodium hydroxide (1 mmol) was added. The water was evaporated using an infra-red lamp. After heating to dryness, the Saran film was folded and transferred into a polyethylene tube. The radioactivity of 125I was counted with a well type NaI(Tl) scintillation counter. When a multi-channel analyzer was available for counting, an absolute decay rate of 125I was calculated with single and sum photo-peak counts. The radioactivity of 125I counted by a single-channel counter must be corrected with the counting efficiency of about 55%, with a special emphasis of a self absorption of photons. The recovery of 125I for concentrations below the permissible level was more than 98%.
Kawae
M
M
Radioisotope Research Institute, Fukui Medical University School of Medicine.
Wada
M
M
Mori
K
K
Sasaki
Y
Y
Kano
E
E
D007457:Iodine Radioisotopes / Q000032:analysis*; D011834:Radiation Monitoring / Q000379:methods*; D012588:Scintillation Counting; D012722:Sewage / Q000032:analysis*; D014835:Volatilization; D014865:Waste Disposal, Fluid / Q000032:analysis*
D007457:Iodine Radioisotopes; D012722:Sewage