Major functions of ion exchange resins in the BWR condensate demineralizer (CD) are deionization and CRUD removal. Particularly CRUD removal is very important technology for reducing radiation source. Authors found that CRUD removal efficiency of CD resins increased with time in long-term operation. Aging has the effect of changing water retention capacity and surface area of cation exchange resins so as to forward the adsorption, dissolution and diffusion process for amorphous CRUD. Swelling and attrition during long-term use could change the resin properties, and swelling results from oxidative breaking for crosslinking. Thus low crosslinking resins whose properties are similar to those of the aged resins have been developed, and one of them showed fairly good performance for CRUD removal. Nowadays BWR primary coolant requires much purer water containing extremely less impurities, not only CRUD but also organic compounds and silica. From now on various requirements will arise concerning BWR primary coolant. Ion exchange resins would have to meet the requirements.

View full abstract

Clay-intercalated palladium (II) complexes were prepared and characterized by IR, XRD, and XPS measurements. Lithium hectorie (LHT) as a host compound and palladium (II) complexes, [Pd (NH₃) ₄] ²⁺ and [Pd (PDT) ₃] ²⁺, as guest compounds were utilized. The basal spacings of [Pd (NH₃) ₄] ²⁺/LHT (PdAm/LHT) and [Pd (PDT) ₃] ²⁺/LHT (PdPDT/LHT) were 1.30 nm and 2.21 nm, respectively. These intercalation complexes increased in basal spacing when swollen with solvents; i.e. 1.45 nm for PdAm/LHT and 2.94 nm for PdPDT/LHT in DMSO. These intercalation complexes were used as catalysts for the hydrogenation of different alkynes. The activities of the intercalation complexes remarkably depended on the basal spacing and the size of substrates. PdAm/LHT with smaller basal spacing did not hydrogenate phenyl and t-butylacetylene, while PdPDT/LHT bearing lager basal spacing hydrogenated phenylacetylene and aliphatic derivatives only except for t-butylacetylene. These intercalation complexes also exhibited high selectivity for the partial hydrogenation of alkynes.

View full abstract

Surface characteristics of H⁺-multivalent cation forms of ion-exchange resins were investigated by measuring the heats of immersion in 1-nitropropane, water and n-butylalcohol. It was found that the order of heats of immersion in each of the solvents corresponded with that of the dipole moments of each of the solvents. This result suggests that the heats of immersion are affected mainly by the interaction between polar solvents and the ionic sites of the resins. Upon measuring the heats of immersion of H⁺-multivalent cation forms of resins in 1-nitropropane, it was found that the highest heats of immersion were obtained in the case of 50% exchange ratio of H⁺ ions for the Bi³⁺ and Cu²⁺ cations with high electro-negativities. This means that interesting surface characteristics are obtained through exchanging in a certain ratio of the H⁺ ions for multivalent cations with various electro-negativities. Furthermore, hydrated water on the ionic exchange sites seems to influence the surface characteristics of the resins.

View full abstract

In order to reduce the occupational radiation load at BWR (Boiling Water Reactor) and ATR (Advanced Thermal Reactor) type Nuclear Power Plants, it is important to improve the iron removal efficiency at the CD (condensate demineralizer) of feed water system.
The CRUD removal efficiency of CD depends on the cation exchange resin's ability which is known to be improved with time.
The newly developed cation exchange resin “XT-1033” shows a excellent CRUD removal efficiency in the study of applocation at actual plant from fresh age.

View full abstract