Total amount of3H activity in primary coolant due to the operation of Tsuruga Power Station Unit No. 2 was estimated. The3H inventory was measured for samples from the spent fuel pool, primary coolant and miscellaneous tanks. From the result of the measurement and the data of environmental release of3H, the rate of generation of3H in the reactor was found to be 25 TBq/GWa. Since Tsuruga Power Station Unit No.2 is a PWR type reactor, we presume that most of the3H in primary coolant is formed by10B (n, 2α) 3H reaction. It is necessary to release about 23 TBq/GWa of3H to maintain the station inventory at the present level.
The in vitro adsorption on hydroxyapatite (HAP) of99mTc-hydroxymethylene diphosphonate (99mTc-HMDP) and99mTc-methylene diphosphonate (99mTc-MDP), which are used as bone imaging agents, was studied. The adsorption of both diphosphonates was carried out in the concentration of 1.2×10-5and4.7×10-5mol/dm3. Radioactivities of the filtrate and precipitate taken from the adsorptive solution were measured, and the filtrate was analyzed with radio-thinlayer chromatography. The99mTc compounds forming polymers, as previously reported, were remained partially on the precipitate paper at the initial stage of adsorption. The amount of99mTc-HMDP and MDP adsorbed for 1 h was 84% and 77%, respectively, the former adsorbed on HAP to a greater degree than did the latter. The compounds adsorbed on HAP are in a state of adsorption equilibrium with those in the solutions even after adsorbing for 3 h, and seem to be stable.