NSUF 21-4276: Changes in mechanical and chemical-structural properties of gamma irradiated calcium silicate hydrates to an absorbed dose of 189 MGy with respect to pristine samples subjected to the same temperature history ProposalNew
The proposed project objectives are to study the changes in viscoelastic behavior, chemical structure and morphology of calcium silicate hydrates after a gamma dose of 189 MGy. Calcium silicate hydrates are considered the glue of cement and hence are important for the stability of the concrete bio-shield in nuclear power plants. The impact of high gamma doses on the viscoelastic properties of calcium silicate hydrates is not fully understood. Results from previous experiments with samples irradiated to 2.24 MGy and 25 MGy indicate that there may be a creep reduction with gamma irradiation. The proposed experiment will study the impact of a high gamma dose (189 MGy) on the main binding phase of cement to inform models that predict the degradation of cement and concrete with irradiation. Since creep has been proven to delay the onset of irradiation damage, a reduction in creep will certainly impact the level of predicted damage. The use of control samples subjected to the same temperature history than those irradiated will serve to separate heating and irradiation/radiolytic effects. The outcome of the experiments is mainly the production of stress relaxation and creep curves after irradiation, accompanied by the study of chemical-structural properties to understand the factors that may drive the changes in viscous response, such as the loss of water from the interlayer, increase in -OH groups, and/or the precipitation of pseudomorphs. The chemical-structural changes will be studied with thermogravimetry and XRD. Morphology and compositional changes will be examined with SEM. Viscoelastic properties will be obtained through matrices of 100 indents for stress relaxation and creep nanoindentation experiments. The main goal is to inform coupled irradiation-creep-damage predictive models to support the license renewal of the light water reactor US fleet to 80 years of operation. The samples will be available at the end of May and the experiments will be finished in 3 sessions of 5, 5 and 3 days each during June-July.
Additional Info
| Field | Value |
|---|---|
| Abstract | The proposed project objectives are to study the changes in viscoelastic behavior, chemical structure and morphology of calcium silicate hydrates after a gamma dose of 189 MGy. Calcium silicate hydrates are considered the glue of cement and hence are important for the stability of the concrete bio-shield in nuclear power plants. The impact of high gamma doses on the viscoelastic properties of calcium silicate hydrates is not fully understood. Results from previous experiments with samples irradiated to 2.24 MGy and 25 MGy indicate that there may be a creep reduction with gamma irradiation. The proposed experiment will study the impact of a high gamma dose (189 MGy) on the main binding phase of cement to inform models that predict the degradation of cement and concrete with irradiation. Since creep has been proven to delay the onset of irradiation damage, a reduction in creep will certainly impact the level of predicted damage. The use of control samples subjected to the same temperature history than those irradiated will serve to separate heating and irradiation/radiolytic effects. The outcome of the experiments is mainly the production of stress relaxation and creep curves after irradiation, accompanied by the study of chemical-structural properties to understand the factors that may drive the changes in viscous response, such as the loss of water from the interlayer, increase in -OH groups, and/or the precipitation of pseudomorphs. The chemical-structural changes will be studied with thermogravimetry and XRD. Morphology and compositional changes will be examined with SEM. Viscoelastic properties will be obtained through matrices of 100 indents for stress relaxation and creep nanoindentation experiments. The main goal is to inform coupled irradiation-creep-damage predictive models to support the license renewal of the light water reactor US fleet to 80 years of operation. The samples will be available at the end of May and the experiments will be finished in 3 sessions of 5, 5 and 3 days each during June-July. |
| Award Announced Date | 2021-06-07T16:15:04.42 |
| Awarded Institution | None |
| Facility | None |
| Facility Tech Lead | Kory Linton |
| Irradiation Facility | None |
| PI | Nishant Garg |
| PI Email | [email protected] |
| Project Type | RTE |
| RTE Number | 4276 |