1. Application of the Code of Conduct in Polish research reactor MARIA
Regional Meeting on Application of the
Code of Conduct on the Safety of Research Reactors,
Lisbon, Portugal, 2-6 November 2015
Application of the Code of Conduct in Polish research reactor MARIA
Andrzej Gołąb
National Centre for Nuclear Research
Otwock-Świerk, Poland

2. Content Short presentation of High Flux Research Reactor MARIA
The last safety review events of research reactor Maria
PERIODIC SAFETY REVIEW OF REACTOR MARIA
Safety Analysis of the MARIA reactor
4.1. Decrease of the core cooling capability by means of the fuel channel circuit and pool cooling circuit
4.2. Deterioration of the cooling feasibility by the secondary circuit
4.3. Insertion of positive reactivity and power fluctuation
4.4. Failures of the core structural components or experimental equipment
4.5. Accidents induced by external events
4.6. Beyond design accidents
4.7. Accidents induced by internal events
Ageing management
Decommissioning Plan
Emergency Plan for reactor Maria
Conclusion

3. 1. Short presentation of High Flux Research Reactor MARIA
Designed and constructed by Polish industry
First criticality reached in December 1974
1985 ÷ 1991 – modernization period:
Put again into operation in 1992 3

4. General characteristics of MARIA reactor
Nominal power
30MW
Maximum thermal neutron flux:
in fuel
in beryllium
2.5 · 1018 n/m2s
4.0 · 1018 n/m2s
Moderator
water and beryllium
Reflector
graphite (blocks in Al cans) and water
Fuel element:
Material and enrichment
shape
overall dimensions
dispersion U3Si2 in Al. - 19,75% U-235
5 concentric tubes
100 cm length
Primary fuel cooling system:
type of fuel channel
pressure range
temperature, core inlet (outlet), water flow rate:
through channel
total
Field tube
0.8 ÷ 1.8 Mpa
50 (100) ºC
25 m3/h or 30 m3/h
550 ÷ 650 m3/h
Primary pool cooling system:
pressure
temperature:
at core matrix inlet
at core matrix outlet
Water flow rate
Atmospheric
40 ºC
50 ºC
1400 m3/h

5. The main areas of reactor application are:
production of radioisotopes
irradiation of uranium plates for Mo-99 production
testing of fuel and structural materials for nuclear power engineering
neutron radiography
neutron activation analysis
neutron transmutation doping
research in neutron and condensed matter physics
training

6. reactor relicensing – March 2015 updating following documents:
2. The last safety review events of research reactor Maria:
INSARR mission – April 2014
reactor relicensing – March 2015
updating following documents:
safety analysis report,
emergency preparedness plan,
preliminary decommissioning plan,
ageing management programme,
radiation protection programme,
quality assurance programme,
classification of system and components important to safety.

7. 3. PERIODIC SAFETY REVIEW OF REACTOR MARIA
On the base of Atomic Law (art. 37e) NCBJ is obligated to carried out safety review of reactor Maria every 4 years.
Plan of safety review has to be approved by President of National Atomic Energy Agency (Regulatory Body). Plan has to be submitted to the President of NAEA 6 months before beginning of the safety review.
Report of safety review has to be submitted to the President of NAEA, not later than 3 months after carrying out the safety review and has to be approved.

8. 4. Safety Analysis of the MARIA reactor
Classification of abnormal events regarded in Safety Analyses of MARIA reactor is carrying out on the base of Atomic Law and the Regulation of The Council of Ministers of 31 August 2012.
Adapting recommendation of IAEA, contained in Safety Requirements NS-R-4, to specific of reactor Maria the following initiating events were discussed:

9. Coolant flow vanishing in the fuel channel circuit
4.1. Decrease of the core cooling capability by means of the fuel channel circuit and pool cooling circuit
Coolant flow vanishing in the fuel channel circuit
Blocking of coolant flow in a fuel channel
Bypassing of flow through the fuel element
Loss of the tightness in the fuel element cooling circuit
Decline of water flow in the pool cooling system
Water escape from reactor pool cooling circuit
Bypassing of coolant flow rate in the pool through the slots in the core matrix

10. Reactivity disturbances when the reactor is scrammed
4.2. Deterioration of the cooling feasibility by the secondary circuit
4.3. Insertion of positive reactivity and power fluctuation
Reactivity disturbances when the reactor is scrammed
Reactivity disturbances when the reactor start-up
Reactivity disturbances during the operation on nominal power
Reactivity disturbances during fuel storing

11. 4.4. Failures of the core structural components or experimental equipment
Mechanical failure of the fuel element
Failures of core structural components
Loss of air-tightness of the can containing the target material
4.5. Accidents induced by external events
Accidents associated with power supply system
Earthquake impact on reactivity disturbances
Fall of an airplane on the reactor
External flood

12. 4.6. Beyond design accidents
Breach of the main piping or the fuel channel
Partial melting of reactor core
4.7. Accidents induced by internal events
Internal fire
Internal flood
Generally deterministic approach is applied in reactor safety analysis. In the case of mechanical failure of the fuel element and fall of an airplane on the reactor safety analysis are completed by probabilistic approach.

13. 5. Ageing management
Ageing monitoring of reactor systems and components is carried out on the base of procedure: „Ageing management of reactor Maria” No. 03-ZR-15 – updated this year.
This procedure contains the list of reactor systems and components which are surveyed due to ageing and methods and intervals of examination are presented.
To keep the reactor technical state in high level, assuring its safety and disposebility continuous process of reactor modernization is carried out.

14. In the last few years the following important modernization tasks were performed:
implementation of a new neutron measurement lines based on Hartman-Brown’s instrumentation,
implementation of a new instrumentation for controlling thermo-hydraulics reactor parameters such as: temperatures, flow-rates, pressure,
modernization of radiation protection systems, a new system is based on „intelligent” Eberline detectors,
modernization of a fuel elements integrity detection system,
replacement of heat exchangers internals,

15. implementation of a new visualisation and recording system (SAREMA),
modernization of a preparatory station for secondary circuit water supplying system,
implementation of a new visualisation and recording system (SAREMA),
replacement of batteries in emergency electrical supplying system,
Replacement of primary cooling system main pumps.
Besides, the continuous process of ageing control of following important reactor components is being carried out, i.e.:
reactor core beryllium blocks,
reactor reflector graphite blocks,
pipe-lines of primary cooling systems. 15

16. 6. Decommissioning Plan
Preliminary Decommissioning Plan has been elaborated as the consequence of implementation of Code of Conduct.
This plan contains:
Identification of radioactive contaminated materials
Scope of dismantling activities
Description of dismantling technology
Techniques of dismantling
Techniques of decontamination
Waste management
Rules of organization 16

17. The main principles to be undertaken are:
to perform partial decommissioning (safe enclosure)
decommissioning will be carried out as soon as possible after reactor shut-down
decommissioning will be carried out by reactor operational personnel

18. 7. Emergency Plan for reactor Maria
The reactor facility is a part of the National Centre for Nuclear Research (NCBJ). It is physically separated by special protection system.
General Director of NCBJ appoints the Deputy Director of NCBJ for Nuclear Safety and Radiation Protection (DNSRP) and establishes Emergency Service for Nuclear Centre. The Service is aimed to prevent hazardous events, supervise proper preparation of the emergency measures and to mitigate consequences of the accidents. The Service pursues continuous supervision of the condition of the NCBJ facilities.

19. The Emergency Service operates closely with public organizations established to ensure safety. These include: Centre for Radiation Events of National Atomic Agency, Central Laboratory for Radiation Protection, State Fire Brigade, Health Centre in Otwock, Crisis Management Centre in Otwock.

20. EMERGENCY CONSULTANTS
GENERAL DIRECTOR
EMERGENCY MANAGER
of Nuclear Centre
EMERGENCY DISPATCHER
EMERGENCY CONSULTANTS
Chief
of Internal Security Service
Guard
Emergency Managers of Nuclear Facilities
Emergency Groups of Facilities
Deputy for Radiation Protection of Nuclear Centre
Deputy for Radiation Protection of POLATOM
Deputy for Technical Measures
Special Technical Teams
Maintenance Personnel
Fig. 8. An organizational chart of Emergency Service for Nuclear Centre

21. The organization of reactor MARIA operational staff
Reactor Emergency Manager (REM) appointed directly by General Director of NCBJ. Reactor Emergency Group to be called Emergency Service for the reactor MARIA facility. The group consists of selected and trained members of the operational staff. REM is the manager of the reactor MARIA operational staff. The following is associated with the position of REM: deputy manager of the MARIA reactor and manager of the reactor shift.

22. Emergency levels
Emergency Plan identifies the following levels of hazard:
internal – in the reactor site,
local – in the area of the Nuclear Centre,
public – outside the Nuclear Centre.
The limits are established in the Emergency Plan which are the basis for making decision to start the emergency actions.

23. Practical training includes:
emergency exercises including cooperation of involved units (Reactor Emergency Group, Emergency Dispatcher of Nuclear Centre, technical services, internal protection services, external units)
emergency equipment usage

24. 8. Conclusion
Significant improvements in application of the Code of Conduct are following:
Assuring of full independence of Regulatory Body and Operating Organization
Elaboration of succession plan for the personnel to assure adequate human resources needed for safe reactor operation
Reorganization of radiological zoning inside reactor building
Development of ageing management programme
Elaboration of classification of system and components important to safety
Development of maintenance program
Modification of reactor ventilation system in order to minimize radioactive releases in accident conditions 24 24

25. New activities in implementation of the Code of Conduct are following:
Development of procedure for the core configuration change
Assuring the independence of reactor radiation protection officer from the reliance of reactor manager
Improvement of reactor protection system to assure redundancy of some safety channels

26. Thank you for your attention