Theta Consult Ltd.

Complete engineering in the field of radiation protection and radiation control

Theta Consult Ltd. is a Bulgarian private company with a long history and impeccable reputation in the field of radiation control and radiation protection.


Theta Consult Ltd was established in 1994, by professors and science workers from the Faculty of Physics at Sofia University “St Kliment Ohridski”, leaded by Prof. Dr. Tsvetan Bonchev. Initially, all efforts were focused on investigating the aftermath of the Chernobyl accident, as well as solving important problems at NPP Kozloduy.
Subsequently, the activities expanded but remained related to radiation control and radiation protection – measurement of radiation parameters, delivery and service of radiation monitoring equipment, transportation of radioactive substances, etc.
(More information regarding the present company activities, can be found in the sections Services and Supplies.)

Prof. Tsvetan Bonchev (1929 – 1995)Елешница-юли-2016-11-1200x803.jpg

The Team

Theta Consult’s team was established by former teachers from the Faculty of Physics of Sofia University „St. Kliment Ohridski“, former workers from NPP Kozloduy as well as many young spcialists (Physicists and Engineers), who graduated from Sofia University „St. Kliment Ohridski“ and the Technical University of Sofia. This is how we achieved to build the connecting link between the generations of specialists and ensured the transfer of valuable knowledge in the area of radiation protection.


The company’s management team consists of General Managers and Team Leaders.
General Managers are:

Mr. Tsvetan Andreev
General Manager of Theta Consult since 2007. Before that he worked for 33 years, 3 months and 1 day at NPP Kozloduy, entirely engaged with radiation protection.
He took part in the 21st Bulgarian Antarctic Expedition (BAE) 2012-2013. He is also a river and a sea captain, a sailor, a scuba diver, a skier and a horse rider.Сапарева-баня-ММ-12.2015-97.jpgСапарева-баня-ММ-12.2015-86.jpg

Mr. Yavor Andreev
General Manager of Theta Consult since 2016 after 10 years of working at different positions in the company. He holds a Bachelor’s degree in Industrial Engineering in English from Technical University of Sofia. He also holds a Master’s degree in Population Protection and Critical Infrastructure from the Military Academy “G.S. Rakovski” in Sofia.
He is a Chairman of baseball and softball club, a river and a sea captain, a passionate skier and a mountain biker. He is a Deputy Chairman of the youth section of the Bulgarian Nuclear Society.

Licences and Permissions

Theta Consult Ltd. holds all necessary licenses and permissions, required for operating in it’s specialized area.
The company has developed and applies in it’s operation certified systems for quality management, information security management and management of operational health and safe working conditions.
The operational staff is qualified to work with sources of ionizing radiation and to transport radioactive substances (ADR), as well as to provide consultancy services on these topics.ЛИЦЕНЗИЯ_ПРЕВОЗ_РАВ-Т-5506.jpg

Licence for Transportation of Radioactive Substances

Transportation of radioactive substances is carried in accordance with European agreement for transport of hazardous loads by road – ADR. Following the ADR classification, the radioactive substances are classified as Class 7. Most often, such kinds of loads are medical radioisotopes or industrial sources of ionizing radiation.ЛИЦЕНЗИЯ-ЗА-РАБОТА-С-ИЙЛ.jpg

Licence for Operation with Ionizing Radiation Sources

The licence for operation with sources of ionizing radiation is issued by the Nuclear Regulatory Agency and allows operation with sources of ionizing radiation, for the purposes of technical service, installation and dismantling of specialized equipment, as well as measurement of radioactive parameters.

Management Systems

ISO 9001:2015

Theta Consult Ltd owns certified System for Quality management since 2001. In 2018 the company migrated to the new revision of the standard БДС EN ISO 9001:2015

Theta Consult Ltd operates under the slogan

“When quality is a priority, the success is not delayed!”Сертификат_СУК_2020.jpgСертификат_СУЗБУТ_2020.jpg

ISO 45001:2018

Since 2016 Theta Consult Ltd owns a certified system for management of operational health and safety labor conditions, in accordance with BS OHSAS 18001:2007, and in 2019 migrated to the new standard (БДС ISO 45001:2018)

ISO 27001:2017

Since March 2020 Theta Consult Ltd owns certified Information Security Management System, in accordance with БДС EN ISO/IEC 27001:2017.


represented at the Bulgarian market

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For the quality and timely execution of orders/contracts for the supply of products or provisioning of services, Theta Consult Ltd. receives often References or Good Performance Certificates from its various customers.


Executive Environment Agency (ExEA) expresses it’s positive opinion and satisfaction from the performance of the operations in the laboratories for radiation measurements of ExEA, and recommends Theta Consult Ltd as a correct partner.

Kamelia Radeva

Border Police

The high level of professionalism of the managers and the specialists of Theta Consult Ltd, contributes for the successful performance of the tasks of General Directorate “Border Police”.

Zaharin Panov
Chief Commissioner

NPP Kozloduy

The contract is finished in time, with a very good quality.

N. Nikolov
Head of Laboratory for sources of ionizing radiation

National Centre of Radiobiology and radiation protection

Extremely professional and responsible attitude to the jobs.

Prof. R. Georgieva


The professional and responsible attitude to the performed activities gives reason to LUKOIL Neftochim Burgas to recommend Theta Consult Ltd. as a reliable and correct partner.

Chief Enineer


Our cooperative work with Theta Consult has been performed with a spirit of partnership and mutual understanding.

Craig W. Nelson
Core Program Manager


Theta Consult Ltd. works with various legal and private persons, representatives of the state and private business, participants at the labor market.

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20, Lavski rid St.                                1680 Sofia                                           Bulgaria


phone: +359 2 964 0950             mobile: +359 885 105975                      e-mail: