NB/T 20003.7-2021Non-destructive testing for mechanical components in nuclear island of nuclear power plants - Part 7: Visual testing (English PDF)

3.1 direct visual testing

visual testing method where there is a continuous light path between the testing personnel's eyes and the testing area

Note: The testing can be conducted without the aid of any equipment, or with the assistance of mirrors, or lenses (but not including telescopes).

3.2 remote visual testing

visual testing method where there is a discontinuous and intermittent light path between the testing personnel's eyes and the testing area

Note: The testing can be conducted using photography, video systems, automated systems, and robots.

3.3 neutral gray card

cardboard providing 18% reflectance neutral gray

Note: The neutral gray card used for visual testing typically features black lines with a width of less than or equal to 0.8 mm, used for verifying resolution.

4.1 Visual testing personnel

The requirements specified in 5.1 of NB/T 20003.1-2021 shall apply.

Testing personnel shall undergo an examination of visual acuity annually. Their uncorrected or corrected near and far visual acuity shall not be less than 4.8, and the test method shall meet the requirements of GB 11533.

The testing personnel shall undergo color vision examination annually, and such examination shall not reveal color blindness or color weakness.

4.2 Testing documents

4.2.1

The testing documents shall include testing procedures, process cards, testing checklists, and other detailed testing documents, which shall meet the requirements of 5.4 in NB/T 20003.1-2021. Visual testing shall be carried out according to the effective written testing procedures.

4.2.2

The testing procedures shall cover at least the following contents:

——scope of application: type, size, testing range, and material of the workpiece under test;

——quoted laws, regulations, standards, design documents, etc.;

——qualification of testing personnel;