According to the Notice on Development and Revision of the First Batch of Energy Industry Standards in 2009 （GNKJ （2009） No. 163） issued by the National Energy Administration of the People's Republic of China.
In preparing this code，the drafiing staff made wide investigations，research，and data collection，reviewed the test methods and data concerning density and moisture measurement by nuclear methods used in China and abroad，and incorporated into this code the latest research findings on nuclear densitometer gauges.
This code covers the technical requirements for nuclear densitometer gauges，testing，standard count，gauge calibration，in-place test procedure，as well as safety protective measures.
In this code，the sub clauses in bold are compulsory and must be enforced strictly.
This code is proposed by the China Electricity Council.
flus code is under the jurisdiction of the Technical Committee on Standardization of Hydropower Construction in Electric Power Industry.
Any comments and suggestions proposed during the execution of this code are to be referred to the Standardization Center of China Electricity Council at the following address： No.l，Ertiao Lane，Baiguanglu Road.，Beijing 100761，China.
