An Investigation of cementitious materials for radioactive waste repository; Mechanical properties of law alkalinity cementitious materials

Owada, Hitoshi*; Mihara, Morihiro; Iriya, Keishiro*; *

JNC TN8400 99-057, 43 Pages, 2000/03

JNC-TN8400-99-057.pdf:5.13MB

Cementitious materials are considered as candidate materials for the geological disposal of high-level radioactive waste and TRU waste. As the pH and the Ca content of leachate from the cementitious materials are high, the host rock and the buffer-material would be degraded by the leachate in the long-term. Therefore, transport properties and parameters such as solubilities and distribution coefficients of radionuclides would be changed and affect the performance of the repository. In order to dissolve this "High pH plobrem", the use of a low alkalinity cement is considered for the disposal. In this study, we summarized the necessity of the low alkalinity cement, and developed the approach of the low alkalinization of cement. And, the following were carried out in this study : A leaching test of cement paste, a fluid test of the mortar and a installation test of the concrete to the trial structure. From the leaching test using the cement paste, we confirmed that we were able to obtain the low alkalinity cement (HFSC) by addition of pozzolanic materials such as silica-fume and flyash. From the result of the fluid test of the mortar, we chose the cement for the practicability evaluation. The practicability of low alkalinity concrete was evaluated by installation test to the trial structure.As a result of these examinations, we proved that the pH value of the leachate from the cementitious material was reduced by adding SF and FA to Portland cement. Simultaneously, SF and FA had to be added in order to obtain the good workability. In addition, workability and mechanical strength of the cement which SF and FA were added are almost equivalent to the ordinary Portland cement. The results shows that the HFSC has high practicability.

PNC Technical Review No.107

PNC TN1340 98-003, 126 Pages, 1998/09

PNC-TN1340-98-003.pdf:17.88MB

no abstracts in English

Effect of direct contact with iron on gas evolution behavior of aluminum

Hashizume, Shuji; Matsumoto, Junko; Bamba, Tsunetaka

Genshiryoku Bakkuendo Kenkyu, 5(1), p.45 - 49, 1998/08

http://ci.nii.ac.jp/naid/40005195032

no abstracts in English

Gas evolution behavior of aluminum in mortar

Hashizume, Shuji; Matsumoto, Junko; Bamba, Tsunetaka

JAERI-Review 96-013, 25 Pages, 1996/10

JAERI-Review-96-013.pdf:1.06MB

no abstracts in English

None

PNC TJ7552 92-002VOL1, 73 Pages, 1992/04

PNC-TJ7552-92-002VOL1.pdf:5.12MB

no abstracts in English

Sodium spray fire analysis (II)

; *

PNC TN241 83-10, 229 Pages, 1983/07

PNC-TN241-83-10.pdf:13.91MB

Sodium spray fire experiments using a 21 m vessel were Performed in order to validate the computer code SPRAY-III. The results of precalculations has been reported in a preceding report, Sodium Spray Fire Analysis. In this study, the validation of SPRAY-III was conducted using the experimental results and the accuracy of calculated results was discussed. The following results were obtained: (1)study under inert gas atmosphere. (a)The peak pressure and temperature obtained by the analysis overestimate the experimental results. But the calculated pressure rose monotonically till the termination of spray injection and it was different from the experimental peak which appeared during the injection. The rise rates of pressure and temperature in analyses were lower than those in experiments. (b)The calculated temperatures of the steel wall liner were only about 55 to 75 % of the experimental values at the end of sodium injection. But the comparison between analysis and experiment with regard to the temperature of mortar wall showed a fairly good agreement. (c)The averaged pool temperature at the end of sodium injection was found to be slightly lower in analysis than in experiment. The analysis shows that the heat transfer between the pool and the gases hardly affects the results during sodium injection. (2)Study under air atmosphere. (a)When all reaction products were assumed to be peroxide in the same manner as in the safety analysis of Monju, the increase rates of both the pressure and the temperature as well as their peak values were found to be underestimation. Hence to obtain conservative results in this 21 m vessel, an increase in the rate constant of reaction with oxygen (Vo from 300 to 1000 ft/sec) must be assumed. However, this value should be investigated in the near future for application to the safety analysis of Monju. (b)The comparison between analysis and experiment with regard to the temperature of the mortar showed a fairly good agreement. ..