What is Decree No. 195 / 1999 Coll.?

Decree of the State Office for Nuclear Safety No. 195 / 1999 Coll., on requirements for nuclear equipment to ensure nuclear safety, radiation protection and emergency preparedness — Decree of the State Office for Nuclear Safety on requirements for nuclear equipment to ensure nuclear safety, radiation protection and emergency preparedness.

When it became Decree No. 195 / 1999 Coll. effectiveness?

Decree No. 195 / 1999 Coll. became effective 03.09.1999.

Is Decree No. 195 / 1999 Coll. still valid?

Yes, Decree No. 195 / 1999 Coll. is still valid and effective.

How many times was it Decree No. 195 / 1999 Coll. amended?

Decree No. 195 / 1999 Coll. has 2 time versions of the text.

Decree No. 195 / 1999 Coll. - Decree of the State Office for Nuclear S...

195

DECLARATION

State Office for Nuclear Security

of 21 August 1999

on requirements for nuclear equipment to ensure nuclear safety, radiation protection and emergency preparedness

According to Section 47 (7) of the State Nuclear Safety Authority, for the implementation of Section 13 (3) (d) and Part A (I. 2) of the Annex to Act No. 18 / 1997 Coll., on the Peaceful Use of Nuclear Energy and Ionising Radiation (Atomic Act), and amending and supplementing certain laws:

ČÁST PRVNÍ

GENERAL PROVISIONS

Subject matter

§ 1

This decree sets out the requirements for the solution of nuclear installations to ensure nuclear safety, radiation protection and emergency preparedness.

§ 2

For the purposes of this decree:

(a) the lowest realisable dose values of ionising radiation optimised in terms of radiation protection under specific legislation, 1)

(b) by normal operation, all states and operations of the planned operation of the nuclear installation, subject to the limits and conditions of safe operation of the nuclear installation; This appropriation is intended to cover the financing of commitments remaining to be settled from previous years.

(c) abnormal operation of a state, operation and event that deviates from a normal operation that is unplanned but is likely to occur when a nuclear installation is operated; These are, for example, rapid unsetting, sudden drop in load, turbine failure, power loss, major circulatory pump failure, etc.; These operating conditions shall not lead to damage to the fuel system or to a breach of fuel elements and a breach of the integrity of the primary circuit; after their completion or removal of the causes and consequences, the nuclear installation is capable of normal operation;

(d) a fuel element of a design unit the basic component of which is nuclear fuel; includes cover, fuel tablets, filling gas, springs, closures, etc.,

(e) a fuel pool of fuel elements which are normally not analysed when the fuel is exchanged in the reactor; includes, in addition to fuel elements, distance grates, upper and lower casings, if any, guide tubes for internal instrumentation or for bundles of control bars or for neutron sources or for files with discrete burning absorbers and cover of the fuel file,

(f) fuel system of fuel sets and their components, internal control components of the active zone as control rods, flaming absorbers, if used, neutron power rods, support plates, etc.,

(g) by violating fuel elements in the distortion of hermeticity of coverage and thus the possibility of leakage of fissile products into the surroundings;

(h) damage to the fuel system of the fuel element breach or exceeding the dimensional tolerance for operational conditions or change of performance beyond the limit considered in the safety analyses;

(i) project limits for normal and abnormal operation of parameters to which the ability to perform project functions is ensured and to prevent the illicit release of radionuclides into the environment;

(j) emergency conditions all events caused by failure or breach of construction structures, technological files and equipment, external influences or operator errors which lead to a breach of the limits and conditions of safe operation and which may cause damage to the fuel system or a breach of the fuel elements;

(k) by a project accident, an accident considered in a project solution of a nuclear installation which may result in the release of radionuclides, ionising radiation or exposure of persons;

(l) the maximum project accident project accident considered in the design of a nuclear installation with the greatest radiological consequences;

(m) the limit parameters of the fuel elements, the maximum parameters of the fuel elements and the degree of damage which must not be exceeded in normal and abnormal operation;

(n) a simple failure event leading to a loss of the ability of an element to perform a specified function, all other elements working correctly; subsequent failures caused by an initial single disorder are considered to be part of this simple disorder.

ČÁST DRUHÁ

ESSENTIAL REQUIREMENTS FOR NUCLEAR SAFETY, RADIATION PROTECTION AND HAVARIAN PREPARATIONS

§ 3

Deep protection

The nuclear safety of nuclear installations shall be ensured by means of protection to a depth based on the use of multiple physical barriers to the spread of ionising radiation and radionuclides into the environment and with the repeated application of a system of technical and organisational measures to protect and maintain the effectiveness of such barriers, as well as the protection of workers and other persons, the population and the environment.

§ 4

Quality requirements

(1) Construction structures, technological assemblies and equipment (hereinafter referred to as "equipment") relevant to nuclear safety of nuclear installations and radiation protection must ensure their reliable function in normal and abnormal operation and the ability to reduce the consequences of failures and accidents.

(2) Equipment relevant to the nuclear safety of nuclear installations shall be designed to enable the status check and tests of their functional capabilities and reliability by methods corresponding to the present state of science and technology to be carried out in operation. The technical solution of these installations shall include security measures to compensate for undetected damage during the operation of the nuclear installation.

(3) The quality and suitability of the calculation programmes used for analyses relevant to nuclear safety must be verified.

§ 5

Radiation protection in and around nuclear facilities

The nuclear device shall have radiation protection in and around its objects under specific legislation. 1)

§ 6

Emergency preparedness in and around the nuclear facility

The nuclear installation shall have emergency preparedness in and around the nuclear installation according to specific legislation.2), 3)

§ 7

Protection against equipment failures

Nuclear-safety-critical equipment shall ensure, in normal and abnormal operation, tests and emergency conditions, that they are not damaged due to disturbances of other equipment within the nuclear installation. Therefore, it must be able to withstand changes in the environment associated with these disorders and be suitably located and adequately protected from dynamic and other effects (cast objects, pipe vibration, fluid leakage, overload of higher pressure).

§ 8

Heat extraction

(1) The technological files and equipment involved in the separation of heat released by fission, residual and operational heat shall ensure reliable cooling of the reactor under normal and abnormal operation and emergency conditions.

(2) Heat extraction systems shall be backed up, physically separated and interconnected to the extent necessary to fulfil their function even in a simple failure.

§ 9

Fire protection

(1) Equipment relevant to nuclear safety must be designed and located in such a way as to meet the fire protection requirements and other requirements laid down in specific legislation; 4)

(2) Non-flammable substances or substances with reduced combustible properties shall be used in nuclear safety-critical devices.

(3) Nuclear equipment objects shall be equipped with an electrical fire alarm and a fixed fire extinguisher designed in such a way that, in the event of failure or accidental entry into service, the functional capability of the nuclear safety-critical equipment of the nuclear installation is not affected.

(4) A fire hazard assessment shall be carried out for objects relevant to the nuclear safety of the nuclear installation.

(5) A nuclear installation involving a nuclear reactor with a power output above 50 MWt must be provided from the construction stage by the fire protection unit of the permit holder.

§ 10

Protection against phenomena caused by natural conditions or human activity outside nuclear installations

(1) Equipment relevant to the nuclear safety of nuclear installations must be designed in such a way that, in the event of natural events that can be expected to occur (earthquakes, storms, floods, etc.), or events caused by human activity outside the nuclear installation (aircraft crash, explosions around the power plant, etc.), it is possible to:

(a) the reactor is safely shut down and maintained in a subcritical state;

(b) carry out the residual power of the reactor for a sufficient period of time;

(c) ensure that any radioactive leakage does not exceed the values laid down in special legislation.1)

(2) When designing a nuclear installation, consideration shall be given to:

(a) the most serious natural phenomena, historically recorded in and around the site, extrapolated taking into account the limited accuracy of values and time;

(b) a combination of the effects of natural or human activity and emergency conditions caused by such phenomena.

§ 11

Physical protection

Nuclear equipment shall be designed in such a way as to ensure the physical protection of nuclear equipment and materials. 5)

§ 12

Joint use of equipment

For multiple-block nuclear installations which envisage the joint use of nuclear safety-critical equipment, it shall be demonstrated that this solution will not affect its safe operation. In doing so, consideration should be given to the occurrence of emergency conditions for one block and the possibility of proper unsetting and cooling of the remaining blocks.

ČÁST TŘETÍ

ACTIVE REACTOR ZONE

§ 13

Reactor active zone solution

(1) The active zone and the relevant cooling, control and protection systems shall ensure with reserve that the specified project limits are not exceeded during any operational condition.

(2) The reactor active zone and the downstream cooling, control and protective systems must ensure that the resulting effect of immediate feedback in the active zone prevents a rapid increase in reactivity in all critical reactor operating states.

(3) The mechanical parts forming an active zone or mechanical parts situated close to it, including their fixing, must be so designed as to withstand static and dynamic effects in normal and abnormal operation. In the event of an emergency, any breach shall not prevent the reactor being shut down and the cooling of the core.

§ 14

Fuel system solution

(1) The fuel system must withstand the projected exposure in the active zone without damaging it in normal and abnormal conditions, despite all the material deterioration processes considered and the environmental conditions that may occur during operation.

(2) The processes under consideration for deterioration of material properties and environmental conditions must include the application of external coolant pressure, the increase of internal pressure in the fuel element due to fissile products, the exposure of fuel and other fuel file materials, the changes in pressures and temperatures resulting from power changes, chemical effects, static and dynamic stress, including stress caused by coolant flow and the effects of mechanical vibration and changes in heat transmission that may occur as a result of deformations or chemical effects. Uncertainties in data, calculations and manufacturing tolerances shall be respected with an adequate margin.

(3) The specified fuel project limits for normal and abnormal operation, including the permissible leakage of fissile products, must not be exceeded in normal and abnormal operation, while the conditions which may occur in the active zone during abnormal operation must not cause an additional significant deterioration of the fuel system's projected characteristics. The leakage of fissile products must be kept below a minimum value which is practically achievable.

(4) In the emergency conditions of the project accident, the fuel elements and the files must remain in place and must not succumb to such damage as would prevent the absorption organs from being inserted or to prevent the active zone from cooling effectively.

(5) The specified fuel project limits for the emergency conditions of the project accident must not be exceeded.

(6) The design solutions of the fuel files shall allow adequate control of their parts.

(7) The implementation of the fuel files shall be sufficiently experimentally or operationally documented.

§ 15

Neutron flow distribution

(1) For all levels and distribution of neutron flow that may occur during all conditions of the active zone, including those after weaning and during or after the transhipment of fuel and those arising during abnormal operation and during emergency conditions, paragraphs 1 to 5 of Article 14 shall be complied with.

(2) The neutron flow distribution equipment shall be able to detect areas of the active zone in which the level and distribution of the neutron flow could cause fuel project limits to be exceeded for normal and abnormal operation and emergency conditions. The design solutions of the active zone shall support the ability of the control system to maintain the level and course of neutron flow within the prescribed limits in all active zone states during normal and abnormal operation.

(3) The active zone and the relevant cooling, control and protection systems shall be so designed as to ensure that power oscillations which could cause the specified fuel project limits to be exceeded cannot or will be reliably and immediately detected and suppressed.

ČÁST ČTVRTÁ

MANAGEMENT AND PROTECTION SYSTEMS

§ 16

Control systems

(1) The control systems on nuclear installations shall be equipped with instruments to monitor, measure, register and control the operational parameters relevant for ensuring nuclear safety during normal and abnormal operation and in emergency conditions. Communicators and controllers shall be designed and deployed in such a way that the operator is constantly provided with sufficient information on the operation of the nuclear equipment and can intervene operatively if necessary. Control systems shall give the required signals on deviations of important operational parameters and processes from the permissible limits.

(2) Control systems shall record, at regular intervals or as appropriate, values of parameters that are relevant to nuclear safety of nuclear installations according to emergency analysis.

(3) When emergency conditions arise, instrumentation shall provide:

(a) information on the immediate state of the nuclear installation on the basis of which protective measures may be taken;

(b) basic information on the progress of the accident and its record;

(c) information enabling the spread of radionuclides and radiation to the vicinity of a nuclear installation to be characterised so that measures can be implemented in time to protect the population.

§ 17

Protective systems

Nuclear installations involving a nuclear reactor shall be equipped with protective systems which shall be:

(a) be able to recognise abnormal conditions and automatically activate the relevant systems, including the shut-down system referred to in Section 21, to ensure that project limits are not exceeded;

(b) be capable of identifying emergency conditions and putting into operation relevant systems designed to mitigate the consequences of such conditions;

(c) the activities of the control systems and the operation of the nuclear equipment are superior in all states considered in the design of the nuclear equipment, while the operator must be able to activate the protective system manually.

§ 18

Backup of protection systems

(1) Protective systems must be dealt with with with high functional reliability, multiplication and independence of individual channels in such a way that:

(a) no simple failure has caused the system to lose its protective function;

(b) the disconnection (decommissioning) of any component or channel has not resulted in a reduction of the number of independent (redundant) components or channels to one, unless the acceptable reliability of the operation of the protection system cannot be demonstrated in such a case.

(2) Protective systems must allow for periodic testing of the function of individual independent channels in the operation of the reactor and testing of common circuits of independent channels at least at the weaned reactor. These joint circuits shall be designed in such a way that their possible failures lead to the maximum unwinding of the reactor and not to loss of protective function.

§ 19

Relationship of protection and control systems

(1) The protection and control systems must be separated so that the failure of the control systems does not affect the ability of the protection systems to perform the required safety function. The functional and efficient connection of protective and control systems must be limited to the maximum extent that it does not significantly affect nuclear safety.

(2) The protection system must be so designed and set that the project limits cannot be exceeded even if the control system functions badly. Safeguards in all states considered in the design of nuclear equipment are superior to the activities of the control system and the operation of the nuclear equipment.

§ 20

Supervisory

(1) A nuclear installation involving a nuclear reactor must be equipped with at least one operational control unit from which it can be safely and reliably controlled in normal and abnormal operation and even in emergency conditions.

(2) The operational supervisor must be addressed in such a way as to allow access, safe residence and health even under emergency conditions for the protection of operating personnel.

(3) The nuclear installation must enable the reactor to be unloaded and maintained in a safe state, even if the operational control becomes useless. The relevant equipment shall be sufficiently physically and electrically separated from the operational control.

§ 21

Reactor shutdown

(1) The reactor shall be equipped with systems capable of being shut down under normal and abnormal operation and emergency conditions. It must be kept unloaded even in situations causing the highest reactivity of the active zone. The efficiency, speed and weaning reserve shall ensure that the specified project limits are not exceeded.

(2) The decommissioning equipment must consist of at least two different independent systems based on different principles and capable of performing its function even for simple failures.

(3) At least one of the systems referred to in paragraph 2 shall in itself be able to rapidly bring the reactor from normal or abnormal state and emergency conditions into a subcritical state with an adequate margin, provided that a simple failure occurs.

(4) At least one of the systems referred to in paragraph 2 shall in itself be able to put the reactor from normal operation into a subcritical state and to keep the reactor in a subcritical state with an adequate reserve in a situation causing the highest reactivity of the active zone.

(5) When demonstrating the required characteristics of the shut-down device, particular attention shall be paid to failures generated anywhere in the nuclear installation that could deactivate part of those devices.

(6) The shut-down device must be able to prevent spontaneous formation of a critical condition. This requirement shall also be met under activities to increase reactivity in a weaned reactor (e.g. removal of the regulatory authority for the purpose of maintenance or transfer of fuel), even if these devices are simply malfunctioning.

(7) The measurement and test systems shall ensure that the shut-down devices are in the required condition.

(8) Part of these equipment intended for the decommissioning of the reactor may be used in its operation to control the reactivity or to shape the neutron field, provided that the weaning reserve is continuously maintained.

ČÁST PÁTÁ

_

§ 22

Principles for solving the primary circuit

(1) The primary circuit and its auxiliary, control and protection systems must be so addressed that:

(a) the required strength, durability and functional reliability of their parts and equipment have been ensured with sufficient reserve under normal and abnormal operation;

(b) no unacceptable refrigerant leaks have occurred;

(c) they are sufficiently resistant to the formation and development of disturbances and a slow development of potential failures and their early detection has been ensured;

(d) large-scale disorders are excluded,

(e) the action of the pressure relief device (insurance valves) has not caused unacceptable radionuclides to escape from the nuclear installation;

(f) the components of the primary circuit containing the coolant as a pressure vessel, pressure pipes, pipes and their connections, valves, seals, etc., including their fixing, have resisted the static and dynamic stress assumed during all operating conditions and emergency conditions.

(2) The design of the primary circuit equipment must:

(a) determine the materials certified for these purposes and comply with the relevant regulations, technical standards or technical conditions;

(b) provide evidence of theoretical calculation and experimental verification of their adequate dimensioning;

(c) include provisions for deterioration of material properties which may occur during operation due to erosion, corrosion, material fatigue, chemical environment, radiation and ageing, and provision for uncertainty as to the determination of the initial condition of components and the rate of deterioration of their properties;

(d) contain an analysis of the limit states due to the formation and spread of integrity disorders;

(e) establish the method of proving the quality of production and assembly using available modern methods and establish the method of proving the required tightness;

(f) identify the programme and methods for determining its status in service.

(3) The design of the primary circuit equipment shall include the conditions of its tests and maintenance, the conditions of normal and abnormal operation, the emergency conditions, the analysis and the solution of all the effects damaging the device.

(4) The design of the primary circuit equipment shall include measures to maintain the quantity or pressure of the refrigerant so that the specified project limits are not exceeded in any of the normal and abnormal conditions of operation, taking into account volume changes and releases.

(5) Systems to maintain the quantity or pressure of the refrigerant shall have adequate capacity (flow or volume) to meet the requirements of Sections 22 (4) and 24 (1).

§ 23

Primary circuit status check in operation

(1) The primary circuit equipment must enable the nuclear installation to carry out periodic or continuous checks of its state in service and tests necessary for the verification of nuclear safety throughout its operation.

(2) The design of the primary circuit equipment includes:

(a) in-service status control programme and diagnostic methods;

(b) criteria for evaluating the control and test results.

§ 24

Coolant replenishment and cleaning system

(1) The refrigerant replenishment system must be capable of compensating for leakage and volume changes of the refrigerant in normal and abnormal operation, taking into account the coolant sampling to be cleaned in order to comply with the specified project limits.

(2) The coolant cleaning system shall be capable of removing corrosion products and fissile products that escape from fuel elements in their potential failures while maintaining the required purity parameters of the primary circuit.

§ 25

Residual heat removal system

(1) The residual heat removal system must ensure that the design limits of the fuel elements and the primary circuit are not exceeded in a weaned reactor.

(2) The residual heat removal system must ensure sufficient backup of the important equipment of the residual heat removal system, appropriate interconnection, the possibility of disconnecting part of the system, the detection of leakage and the possibility of its capture so that the system works reliably even in a simple failure.

§ 26

Emergency cooling system

The emergency cooling system shall ensure:

(a) reliable cooling of the active zone under emergency conditions caused by the loss of the refrigerant, in order to:

1. the fuel element coverage temperatures did not exceed those set by project limits;

2. the energy contribution of chemical reactions (coverage, water, hydrogen release) does not exceed the permissible value;

3. there have been no changes in fuel elements, fuel assemblies and internal parts of the reactor that could affect cooling efficiency;

4. the residual heat has been discharged for a sufficient period of time;

(b) its sufficient backup, appropriate interconnection, the possibility of disconnecting parts of the system, the detection of leaks and the possibility of capturing them so that the system works reliably even in a simple failure.

§ 27

In-service emergency cooling system status check

The emergency cooling system shall allow periodic tests and inspections to be carried out

(a) the strength and tightness of the system;

(b) active elements of the system and their functional testing;

(c) emergency cooling as a whole and its functional testing under conditions corresponding to its operation (sequence of operations which activate individual installations, switching to replacement power supply systems, other cooling water systems, etc.).

§ 28

Secondary circuit

The solution of the secondary circuit must ensure

(a) reliable heat removal from the primary circuit;

(b) the detection of potential releases from the primary to the secondary circuit, and where such releases are detected, they must allow for restrictions on their further spread so as to avoid exceeding the limits of radionuclide discharges.

ČÁST ŠESTÁ

ENERGY TENDER SYSTEMS

§ 29

Energy supply systems

(1) The exercise of nuclear installations and the supply of own consumption must ensure that:

(a) their external and internal distribution disturbances have affected as little as possible the operation of the reactor and the heat drainage systems;

(b) power plant equipment relevant for operation may have been supplied from two different sources (own generator and network of electricity).

(2) In addition, the electrical supply for the power supply of primary circuit control and protection systems, residual heat removal systems, emergency cooling systems and envelope protection systems must enable the supply from an emergency source, i.e. to be backed up without any limitation of power for the time required for the reliable operation of the systems and whether they have their own generators or an electrical system in operation. The control and protection systems shall be supplied continuously.

Citation	Decree of the State Office for Nuclear Safety No. 195 / 1999 Coll., on requirements for nuclear equipment to ensure nuclear safety, radiation protection and emergency preparedness
Regulation Type	Order
Author	-
Collection	Code of Laws

Date of Promulgation	03.09.1999
Effective from	03.09.1999
Effective until	-
Status	Valid

Decree No. 195 / 1999 Coll.

Decree of the State Office for Nuclear Safety on requirements for nuclear equipment to ensure nuclear safety, radiation protection and emergency preparedness

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