Physically based regression correlations of embrittlement data from reactor pressure vessel surveillance programs. Final report

Technical Report · Sun Jan 01 04:00:00 EST 1984

OSTI ID:5336511

Perrin, J F; Wullaert, R A; Odette, G R; Lombrozo, P M

Physically based correlations for irradiation embrittlement, as manifested in shifts in Charpy V-Notch transition temperatures, were developed for plate and welds of light water reactor pressure vessel steels. The data was taken from power reactor surveillance programs contained in the Electric Power Research Institute Irradiated Pressure Vessel Steel Data Base. Alternate physical models, based on irradiation induced production of either small microvoids or copper precipitates acting as the primary source of embrittlement, were used to guide and interpret statistical least square regression analyses. Results demonstrated that the critical embrittlement variables are copper and nickel content and fluence; they suggested that separate correlations should be made for plate and weld conditions. Irradiation temperature, neutron flux and other compositional and metallurgical factors were found to be either unimportant or secondary variables. The statistical correlations were quantitatively consistent with a copper precipitation mechanism, coupled with a phenomenological treatment of synergistic copper-nickel interactions. The correlations yielded mean residual errors of approx. 12 to 13/sup 0/C for plate and approx. 12 to 15/sup 0/C for weld; this is about 33% and 18% of the average shifts, respectively. The correlation results are not unique, but can be reliably applied to a range of conditions clearly identified in the analysis. An upper bound shift of the nominal prediction plus 24/sup 0/C is recommended.

• Research Organization: Fracture Control Corp., Goleta, CA (USA); California Univ., Santa Barbara (USA)
• OSTI ID: 5336511
• Report Number(s): EPRI-NP-3319; ON: DE84920299
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360106* -- Metals & Alloys-- Radiation Effects
ALLOYS
CHEMICAL COMPOSITION
CONTAINERS
COPPER ADDITIONS
COPPER ALLOYS
EMBRITTLEMENT
IRON ALLOYS
IRON BASE ALLOYS
MATHEMATICS
PHYSICAL RADIATION EFFECTS
PRESSURE VESSELS
RADIATION EFFECTS
REGRESSION ANALYSIS
STATISTICS
STEELS
SURVEILLANCE