NB/T 20172-2012Technical rules for nuclear engineering surveying datum network establishment (English PDF)

Foreword

This document was issued on 19 October 2012 by the National Energy Administration of the PRC and takes effect on 1 March 2013.

It is a NB/T standard: recommended rather than compulsory, but it is the text a Chinese reviewer applies when assessing a submission.

It is classified under ICS 27.120.99, Chinese classification F63.

This standard has been drafted in accordance with the rules given in GB/T 1.1-2009.

This standard was proposed by the Technical Committee for Nuclear Power Standardization of the Energy Industry.

This standard is under the administration of the Nuclear Industry Standardization Research Institute.

This standard was drafted under the responsibility of China Nuclear Power Engineering Co., Ltd. The participating drafting organizations are Shenzhen China Nuclear Power Engineering Design Co., Ltd., China Nuclear Industry Huaxing Construction Co., Ltd., and China Construction Second Engineering Bureau Co., Ltd.

The chief drafters of this standard are: Lei Wangcheng, Yin Hongbin, Li Xin, Song Zhanrui, Wang Yafei, Liu Qirui, Cao Luxin, Sun Xiaolong, Gao Jian, Li Guanghua, Yuan Desheng and Luo Kai.

The foreword occupies page III of the printed document and carries no further notes on supersession or on relationships with international standards.

Publication data

Standard designation as printed on the cover: NB/T 20172-2012.

Chinese title on the cover: He dian gong cheng ce liang ji zhun wang de jian li he guan li gui ding (in Chinese characters on the original cover).

English title as printed on the cover: Technical rules for nuclear engineering surveying datum network establishment.

Classification data printed on the cover: ICS 27.120.99; Chinese Standard Classification Code (CCS) F63; record (filing) number 38362-2013.

Issuing body: National Energy Administration of the People's Republic of China. The document is a professional standard of the energy industry of the People's Republic of China (NB series).

Date of issue: 19 October 2012. Date of implementation: 1 March 2013.

The cover carries no supersession note, so this edition does not replace an earlier standard.

Document extent according to the official table of contents: eleven numbered clauses followed by seven annexes, the last of which ends on page 61.

1 Scope

NB/T 20172-2012 sets out how the surveying datum network of a nuclear power project is established and managed. A nuclear plant is built to tolerances that make the control network a safety-relevant item: the reactor building, the turbine hall and the intake structures must be set out from a single consistent framework that does not move or drift over the ten or more years from first excavation to final commissioning, and every settlement measurement made afterwards is referred back to it. The rules define the terms and symbols, then the design of the network - its accuracy classes, the number and siting of monuments, the monument construction that keeps a point stable in the long term, and the relationship to the national and to the site coordinate and height systems. Observation follows: the satellite, total station and levelling methods permitted, the instruments and their calibration, the observation programme and the weather and time constraints on it, the reduction and adjustment of the measurements, and the accuracy assessment of the adjusted network. The rules then cover the densification of the network as construction proceeds, the setting out of structures from it, and the deformation monitoring network derived from it. Finally, and unusually for a surveying document, they set out the management of the network in service: the periodic re-observation, the checking of monument stability, the custody of the records and the handover to the operating organisation.

This standard specifies the layout principles, technical specifications, working methods, collation and submission of results, maintenance of the networks of each level, and the management of instrument use for the surveying datum networks of every level used in nuclear power engineering surveying.

This standard applies to the technical design, field work, inspection and acceptance activities involved in the establishment of surveying datum networks for nuclear power station construction projects.

The scope statement therefore covers the whole life of the datum network, from the design of the network through field observation to the checking and formal acceptance of the delivered results.

2 Normative references

The following documents are indispensable for the application of this standard. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document, including all amendments, applies.

GB/T 12897, Specifications for first and second order levelling.

GB/T 12898, Specifications for third and fourth order levelling.

GB/T 15314, Precision engineering survey specifications.

GB/T 18314, Specifications for Global Positioning System (GPS) surveys.

GB/T 19001, Quality management systems - Requirements.

GB 50026, Code for engineering surveying.

CH 1016, Safety specifications for surveying and mapping personnel.

JGJ/T 8, Code for deformation measurement of building and structure.

3 Terms, symbols and codes

The following terms, symbols and codes apply to this document.

3.1 Terms

3.1.1 surveying datum network: a survey control network that provides the horizontal or elevation surveying datum for the construction of the engineering works, or that serves as the datum for the establishment of a control network of the next lower level.

3.1.2 primary control network: the survey control network established over the area of the nuclear power project. It may be established directly on the basis of the national control network, or an independent coordinate system may be established first and afterwards connected by observation to the national control network.

3.1.2 (continued) The primary control network is used mainly for topographic surveying and mapping, engineering investigation, construction of the early works of the nuclear island, and the construction positioning of the buildings and structures attached to the nuclear power plant.

3.1.3 secondary control network: a free network established on the basis of the primary control network and located around the main plant buildings. Its control point marks are concrete observation pillars fitted with forced centring devices.

3.1.3 (continued) The secondary network serves mainly the positioning and setting out of the buildings and structures inside the main plant area and provides the surveying datum for micro-grid layout, control densification, equipment installation and deformation monitoring.

3.1.4 micro-grid control network: a control network established on the basis of the secondary control network, taking the individual plant building as the unit. Its control point marks are generally embedded in the building foundation slab or in the upper floor slabs.

3.1.4 (continued) The micro-grid network is used mainly for the construction of the internal structures of the plant building and for equipment installation positioning; it is abbreviated to micro-grid.

3.1.5 subsidence deformation monitoring network: the survey control network set up to monitor the subsidence deformation of the buildings and structures of the nuclear power plant. It consists mainly of datum points, working reference points and deformation monitoring points.

3.2.1 Symbols

A: the fixed error in the nominal accuracy of the GPS receiver.

a: the semi-major axis of the earth ellipsoid; also the fixed error in the nominal accuracy of the distance measuring instrument.

a with subscript i j: the semi-major axis of the relative error ellipse between two points.

a with subscript w: the semi-major axis of the point position error ellipse.

B: the proportional error coefficient in the nominal accuracy of the GPS receiver.

b: the semi-minor axis of the earth ellipsoid; also the proportional error coefficient in the nominal accuracy of the distance measuring instrument.

b with subscript i j: the semi-minor axis of the relative error ellipse between two points.

b with subscript w: the semi-minor axis of the point position error ellipse.

C: the collimation axis error.

D: the horizontal distance, on the mean elevation surface of the two ends of the measured side, between those two ends (horizontal length, side length).

D with subscript m: the horizontal distance reduced to the mean elevation surface of the survey area.

D with subscript 0: the length of the measured side reduced to the Gauss projection plane.

D with a further subscript: the horizontal distance reduced to a specified elevation surface.

d with subscript s: the discrepancy in length between repeated measurements of a GPS baseline.

f: the correction to the vertical angle for earth curvature and atmospheric refraction.

H: the elevation.

H with subscript m: the mean elevation of the two end points of the measured side.

H with a further subscript: the mean elevation of the survey area.

h: the height difference.

h with subscript g: the height of the quasi-geoid of the nuclear power engineering area above the reference ellipsoid surface.

i: the angle between the sight axis of the level and the axis of its level tube; the index error; and the transverse tilt error of the angle measuring instrument.

i with a prime: the value of the smallest graduation interval of the horizontal circle.

k: the atmospheric refraction coefficient.

L: the length of the levelling loop or levelling route line.

M: the mean square error.

M with subscript i j: the relative point position mean square error between adjacent points.

M with subscript p: the point position mean square error.

M with subscript W: the total mean square error of the measured height difference per kilometre in levelling.

M with subscript delta: the random mean square error of the measured height difference per kilometre in levelling.

m: the survey mean square error.

m with subscript D: the distance measurement mean square error.

m with subscript t: the azimuth mean square error.

m with subscript g: the fixed angle mean square error.

m with subscripts X, Y and Z: the mean square errors of the point coordinates.

m with subscripts delta X, delta Y and delta Z: the mean square errors of the coordinate increments.

m with subscript a: the angle measurement mean square error.

m with subscript a v, expressed in seconds of arc: the mean square error of a single-trip vertical angle observation.

N: the number of levelling loops, connecting routes, asynchronous loops, traverses or closed loops.

n: the number of observation stations, sets of observations, sections, sides, points, traverse turning angles or triangles.

n with subscript delta: the number of discrepancy values delta.

P: the weight of the observed value.

R: the radius of curvature of the reference ellipsoid; also the repeatability of the GPS baseline.

R with subscript A: the radius of curvature of the normal section arc, on the reference ellipsoid surface, in the direction of the measured side.

R with subscript m: the mean radius of curvature of the reference ellipsoid surface in the nuclear power engineering area.

S: the slope distance after correction for the additive constant, the multiplication constant and the meteorological data (inclined side length).

S with a prime: the side length reduced to the reference ellipsoid surface.

T: the denominator of the relative mean square error of the measured side.

v: the height of the signal target, that is, of the target board or of the prism centre.

W: the triangle closure, the loop closure and the route closure.

W with subscripts a, b, f, g, j and r: the limits of the free terms of, respectively, the circumference angle condition, the side (baseline) condition, the azimuth condition, the fixed angle condition, the pole condition and the combined side and angle condition.

W with subscripts x, y and z: the closures of the coordinate components.

alpha: the observed angle (transmission angle); also the flattening of the earth.

alpha with subscript v: the observed value of the vertical angle.

beta: the observed angle (distance derivation angle); also the turning angle.

delta: the discrepancy or non-conformity value.

delta with subscript c: the closure of the station circumference angle in the left and right angle observation of a traverse.

delta with subscript d: the discrepancy in length between the forward and the backward measurement of a distance.

delta with subscript f: the azimuth closure.

delta h: the discrepancy in height difference.

delta with subscript a: the compensation error of a compensator-type automatic level.

delta with subscript 1 to 2: the direction correction value for the direction observed from station 1 to target point 2.

µ: the mean square error of unit weight.

sigma: the standard deviation, and in particular the standard deviation of a GPS baseline, that is, the baseline measurement mean square error.

3.2.2 Codes

CORS: continuous operational reference system, the integrated service system for continuously operating satellite positioning.

DJ: the model code of angle measuring instruments, that is, optical theodolites, electronic theodolites and total stations. The main model numbers are DJ05, DJ1, DJ2 and DJ6.

DS: the model code of levels, that is, optical levels, including automatic compensation levels, and electronic levels. The main model numbers are DS05 (DSZ05), DS1 (DSZ1) and DS3.

GPS: global positioning system.

GPS-RTK: GPS real time kinematic measurement.

PDOP: position dilution of precision, the spatial position accuracy factor of GPS measurement.

Phi: the diameter.

Structure of the document

The standard is organised in eleven clauses. Clauses 1 to 4 give the scope, the normative references, the terms, symbols and codes, and the general rules that govern the whole document.

Clause 5 covers the primary control network and is the longest clause of the standard, running from page 4 to page 25. It deals in turn with the layout principles, the accuracy indices and layout specifications, the technical design, point selection and monument burial, horizontal angle observation, distance measurement, GPS measurement, levelling measurement, trigonometric levelling by electromagnetic distance measurement, the recording, collation, checking and computation of the observation results, and the submission of results.

Clause 6 covers the secondary control network, from page 25 to page 36, with the same structure of sub-clauses, adding the point marks of the network and the accuracy requirements for the working instruments.

Clause 7 covers the micro-grid network of the plant buildings, from page 36 to page 38, and deals with the layout principles, the accuracy indices, the positioning of the micro-grid, its observation, and the treatment and submission of the results.

Clause 8 covers the densification of the survey control network at each of the three levels, on pages 38 and 39.

Clause 9 covers the subsidence deformation monitoring network, from page 40 to page 41, dealing with its layout principles, its method of establishment and accuracy criteria, the technical requirements for the monitoring, the record keeping and the processing and analysis of the deformation monitoring data, and the submission of results.

Clause 10 covers the maintenance and management of the surveying datum for each of the four networks, on page 42, and clause 11 covers the calibration, inspection, use, transport and maintenance of the surveying instruments, on pages 42 and 43.

Seven annexes follow the clauses: Annex A, informative, gives the parameters of the earth ellipsoid; Annexes B to G are normative and cover point selection, monuments and burial, the inspection and calibration of instruments and equipment, the circle setting table for horizontal angle direction observation, the survey record books, the point marks of the secondary network survey points, and the point marks of the plant building micro-grid survey points.

4 General rules

4.1 These rules have been formulated in order to unify the technical requirements for the establishment of surveying datum networks for nuclear power engineering and to standardise the corresponding technical and management activities.

4.2 The establishment of the surveying datum network for nuclear power engineering shall comply with these rules, with the relevant national surveying codes and with the requirements of the engineering design documents.

4.3 For the surveying datum network of nuclear power engineering the point position coordinate mean square error is taken as the principal index for judging accuracy, and twice that mean square error is taken as the limiting error.

4.4 The establishment of the datum network shall follow the principle of staged and graded layout, in step with the progress of the engineering works.

4.5 Surveying instruments and equipment shall be calibrated and inspected at regular intervals, and the data processing software shall be appraised or verified by the relevant institution.

4.6 The datum networks of each level shall follow the unified numbering system of the nuclear power engineering technical documents. Where a new point and an old point coincide, the old point name should be adopted.

4.7 The organisation contracted to carry out the surveying work for the nuclear power engineering datum network shall hold the corresponding surveying and mapping qualification.

4.8 Organisations engaged in the surveying of nuclear power engineering datum networks shall comply with the national Safety Law and with the Law on Guarding State Secrets, and shall satisfy the safety requirements of nuclear power construction.