NB/T 20325.1-2014 English PDF (NB/T20325.1-2014)

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NB/T 20325.1-2014: Prestressing technology specification for safety containments of PWR nuclear power plants. Part 1: Material
NB/T 20325.1-2014
NB
ENERGY INDUSTRY STANDARD OF
THE PEOPLE’S REPUBLIC OF CHINA
ICS 27.120.99
F 63
Filing No.. 47844-2015
Prestressing technology specification for safety containments
of PWR nuclear power plants - Part 1. Material
ISSUED ON. OCTOBER 15, 2014
IMPLEMENTED ON. MARCH 1, 2015
Issued by. National Energy Administration
Table of Contents
Foreword ... 3 
1 Scope ... 4 
2 Normative references ... 4 
3 Terms and definitions ... 5 
4 Technical requirements ... 7 
5 Inspection rules ... 12 
6 Identifications and packaging ... 17 
7 Transportation and storage ... 18 
Annex A (Normative) Pressure test method for grouting caps ... 19 
Annex B (Normative) Table for the surface quality inspection levels of
prestressing strands ... 20 
Annex C (Normative) Pseudo coagulation test method for cement ... 21 
Foreword
NB/T 20325 Prestressing technology specification for safety containments of
PWR nuclear power plants is divided into 3 parts.
— Part 1. Material;
— Part 2. Test;
— Part 3. Construction.
This Part is Part 1 of NB/T 20325.
This Standard was drafted in accordance with the rules given in GB/T 1.1-2009.
This Standard was proposed by the Technical Committee for Standardization
of Nuclear Power Standards in Energy Industry.
This Standard shall be under the jurisdiction of the Institute for Standardization
of Nuclear Industry.
Lead editorial organization of this Standard. China Nuclear Industry Huaxing
Construction Co., Ltd.
Joint editorial organization of this Standard. China General Nuclear Power
Engineering Co., Ltd.
Participating drafting organization of this Standard. China Nuclear Power
Engineering Co., Ltd.
Main drafters of this Standard. Hao Faling, Wan Jixiang, Liu Qiang, Du
Chunsheng, Yang Gang, Wang Huicheng, Wang Lili, Liao Chunsheng, Zhang
Bo and Zheng Changcai.
Prestressing technology specification for safety containments
of PWR nuclear power plants – Part 1. Material
1 Scope
NB/T 20325 specifies the technical requirements, inspections, symbols and
packaging of the materials, prestressed slurry test, full-scale simulated grouting
experiment, friction test, prestressed construction technology and quality
requirements for the prestressing system for safety containments of PWR
nuclear power plants.
This Part of NB/T 20325 specifies the technical requirements, inspection rules,
symbols and packaging of the materials for the prestressing system for safety
containments of PWR nuclear power plants.
This Part is applicable to the material selection of the prestressing system for
safety containments of PWR nuclear power plants. As for the material selection
of the prestressing system for safety containments of other reactor types of
nuclear power plants, this Part may be referred to for implementation.
2 Normative references
The following documents are essential to the application of this document. For
dated references, only the editions with the dates indicated are applicable to
this document. For undated references, only the latest editions (including all the
amendments) are applicable to this document.
GB 175 Common portland cement
GB 8076 Concrete admixtures
GB 8162 Seamless steel tubes for structural purposes
GB 23439 Expensive agents for concrete
GB/T 228.1 Metallic materials - Tensile testing - Part 1. Method of test at
room temperature
GB/T 1346 Test methods for water requirement of normal consistency,
setting time and soundness of the portland cement
GB/T 1348 Spheroidal graphite iron castings
GB/T 1839 Test method for gravimetric determination of the mass per unit
area of galvanized coatings on steel products
GB/T 2518 Continuously hot-dip zinc-coated steel sheet and strip
GB/T 3091 Welded steel pipes for low pressure liquid delivery
GB/T 5224 Steel strand for prestressed concrete
GB/T 8074 Testing method for specific surface of cement - Blaine method
GB/T 14370 Anchorage, grip and coupler for prestressing tendons
GB/T 17671 Method of testing cements - Determination of strength
GB/T 21839 Steel for prestressed concrete - Test methods
JGJ 63 Standard of water for concrete
JGJ 85 Technical specification for application of anchorage, grip and coupler
for prestressing tendons
JG 225 Corrugated metal ducts for prestressed concrete
JG 3007 Corrosion-resistant and lubricating grease specialized for
unbonded tendons
DL/T 1059 Heat shrinkable tube for bus-bars of electrical equipment
NB/T 20303 Design requirements for prestressed concrete containments for
pressure water reactor nuclear power plants
NB/T 20325.2 Prestressing technology specification for safety containments
of PWR nuclear power plants - Part 2. Test
3 Terms and definitions
The following terms and definitions are applicable to this document.
3.1 Anchorage
It refers to the permanent anchor devices for holding the tension of the
prestressing strand and transmitting it to the concrete, including the bearing
plates, anchor plates and clips.
3.2 Bearing plate
4.3 Steel pipe
It is suitable to use the ERW high frequency welded steel pipes with straight
seams or seamless steel pipes, whose grades are between Q195 and Q345.
The steel pipes shall conform to GB/T 3091 or GB 8162.
The elongation shall be greater than or equal to 15%.
The steel pipes shall be straight. The flexibility of overall length shall be less
than 0.2% of the steel pipe’s length. The diameter deviation shall be ± 1.5mm.
The wall thickness shall not be less than 2mm, with a deviation of -0.2mm or
+0.4mm.
The steel pipes shall be applicable to the flaring and bending requirements. The
inner and outer surfaces shall be smooth and without any overlaps and gas
holes.
4.4 Anchorage
Anchorages shall conform to the requirements of GB/T 14370 and NB/T 20303.
The products requiring tunnel grouting shall be equipped with grout holes or
exhaust holes. The hole sites and hole diameters of the grout holes shall comply
with the requirements for grouting process. Furthermore, the grout holes shall
be provided with the structures connected with the grout pipes.
4.5 Prestressing strand
USE the standard prestressing strands laid by seven steel wires. The tensile
strength shall not be less than 1,770MPa.
During initial type inspection, the specifications, grades and chemical
compositions of the raw materials shall comply with the following requirements.
a) Nominal diameter and deviation. 15.7mm ± 0.2mm.
b) Nominal area. 150 mm2.
c) Nominal mass and deviation. 1.178 kg/m (1 ± 2%).
d) The increased range of the core steel wire’s diameter shall not be less than
3%.
e) The total percentage elongation at maximum force (L0 ≥ 500mm) shall not
be less than 3.5%.
f) Direction of lay. right-hand direction of lay.
requirements of GB 175.
4.9 Mixing water (ice)
The chloride content shall not be greater than 0.025%. Other indicators shall
comply with the requirements of JGJ 63.
4.10 Admixture
The water reducing agent shall use the product with stable properties and good
adaptability with the cement in use. The water reducing rate shall not be less
than 20%. Other indicators shall comply with the requirements of GB 8076. The
retarder shall conform to GB 8076. The water reducing agent and retarder in
use shall have good adaptability.
The expanding agent shall comply with the requirements of GB 23439. It is not
allowed to use the expanding agent using aluminum powder as expansion
source.
4.11 Cement paste
SEE NB/T 20325.2 for the test method.
4.11.1 Water cement ratio
The water cement ratio shall be within the range of 0.30 to 0.38.
4.11.2 Bleeding rate and expansion rate
The bleeding rate of 3h is not suitable to be greater than 2%, and shall not be
greater than 3%. All of the bleeding shall be able to be absorbed by the paste
within 24h.
The expansion rate of the expansive cement paste shall not exceed 6%, and
shall be greater than the bleeding rate.
4.11.3 Setting time
Under the laboratory conditions, the retarding paste’s initial setting time shall
be less than 50h, and the final setting time at 5°C shall be less than 80h.
4.11.4 Fluidity
After stirring for 6h, the retarding cement paste’s fluidity shall be less than 14s.
After stirring for 10h, the retarding cement paste’s fluidity shall be less than 25s.
The ambient temperature is suitable to be within the range of 5°C to 35°C. The
paste temperature is not suitable to be higher than 32°C.
5.1.1 The type inspection refers to the inspection for the overall property
control of the products. CONDUCT the type inspection under one of the
following circumstances.
a) During normal production of the anchorages and prestressing strands with
the same model, the type inspection shall be conducted once every two
years;
b) When there are changes in raw materials and manufacturing process;
c) When resuming production after one-year production halt;
d) When there are major differences between the exit-factory inspection results
and the last type inspection...