TY - JOUR
T1 - The effect of crack length on SIF and elastic COD for elbow with circumferential through wall crack
AU - Kim, Min Kyu
AU - Jeon, Jun Hyeok
AU - Choi, Jae Boong
AU - Kim, Moon Ki
N1 - Publisher Copyright:
© 2020 Korean Nuclear Society
PY - 2020/9
Y1 - 2020/9
N2 - Many damages due to flow-accelerated corrosion and cracking have been observed during recent in-service inspections of nuclear power plants. To determine the operability or repair for damaged pipes, an integrity evaluation related to the damaged piping system should be performed by using already proven code and standards. One of them, the ASME Code Case is most popularly used to integrity assessment in nuclear power plants. However, the recent version of CC N-513 still recommends the simplified method which means a damaged elbow is assumed as an equivalent straight pipe. In addition, to enhance the accuracy integrity assessment in elbow, several previous studies recommend that the SIF and elastic COD values for an elbow with relatively large crack could be predicted by an interpolation technique. However, those estimates for elbow with relatively large crack might be derived to inaccurate results for crack growth analysis, such as for the allowable crack size and life estimation. Therefore, in this paper, the effect of crack length (0.3≤θ1/π ≤ 0.5) on SIF and elastic COD for elbow is systematically investigated. Then, for large crack in elbow, accurate estimates for SIF and elastic COD, which are widely used to assess the integrity of elbows, are proposed. Those proposed solutions are expected to be the technical basis for revisions of CC N-513-4 through the validation.
AB - Many damages due to flow-accelerated corrosion and cracking have been observed during recent in-service inspections of nuclear power plants. To determine the operability or repair for damaged pipes, an integrity evaluation related to the damaged piping system should be performed by using already proven code and standards. One of them, the ASME Code Case is most popularly used to integrity assessment in nuclear power plants. However, the recent version of CC N-513 still recommends the simplified method which means a damaged elbow is assumed as an equivalent straight pipe. In addition, to enhance the accuracy integrity assessment in elbow, several previous studies recommend that the SIF and elastic COD values for an elbow with relatively large crack could be predicted by an interpolation technique. However, those estimates for elbow with relatively large crack might be derived to inaccurate results for crack growth analysis, such as for the allowable crack size and life estimation. Therefore, in this paper, the effect of crack length (0.3≤θ1/π ≤ 0.5) on SIF and elastic COD for elbow is systematically investigated. Then, for large crack in elbow, accurate estimates for SIF and elastic COD, which are widely used to assess the integrity of elbows, are proposed. Those proposed solutions are expected to be the technical basis for revisions of CC N-513-4 through the validation.
KW - Circumferential though-wall crack
KW - Crack length
KW - Elastic crack opening displacement
KW - Elbow
KW - Finite element analysis
KW - Stress intensity factor
UR - https://www.scopus.com/pages/publications/85079156384
U2 - 10.1016/j.net.2020.01.035
DO - 10.1016/j.net.2020.01.035
M3 - Article
AN - SCOPUS:85079156384
SN - 1738-5733
VL - 52
SP - 2092
EP - 2099
JO - Nuclear Engineering and Technology
JF - Nuclear Engineering and Technology
IS - 9
ER -