There are two kinds of post-tensioning system for nuclear power plants. one is bonded-type and the other is unbonded-type post-tensioning system. It is difficult to directly evaluate the effective tensile force of tendon in the case of bonded-type. Therefor, it can be evaluated by system identification(SI) method. In order to use SI technique, it should be obtained the strain measurement results of the containment building wall. This paper is mainly focused on the stain measurement according to the internal pressure of containment building using fiber optic sensor and tried to use it as a basic data of the SI technique in the future.

Abstract
 1. 서 론
 2. 변형률 계측
 3. 평가결과 및 고찰
 4. 결 론
 참고문헌

• 이홍표(한국수력원자력 중앙연구원) | Lee, Hong Pyo 교신저자
• 조명석(한국수력원자력 중앙연구원) | Cho, Myung Sug
• 이금석((주)에프비지코리아) | Lee, Geum Suk