Regulatory oversight of nuclear safety in Finland : Annual report 2014
Kainulainen, Erja (2015-07-01)
Kainulainen, Erja
Säteilyturvakeskus
01.07.2015
Julkaisun pysyvä osoite on
https://urn.fi/URN:ISBN:978-952-309-270-9
STUK-B : 191
https://urn.fi/URN:ISBN:978-952-309-270-9
STUK-B : 191
Kuvaus
1. painos
Tiivistelmä
Management review
In 2014, all Finnish nuclear power plants operated safely and caused no danger to their surrounding environment or employees. The collective radiation doses of employees were yet again historically low and the radioactive releases into the environment very small. The low employee radiation doses were the result of short annual outages and improvements implemented by the NPPs. Radioactive waste generated in the operational processes of the NPPs accumulated as anticipated. Its processing and final disposal in underground facilities took place in a controlled manner. An emergency preparedness drill was arranged at the Loviisa NPP in November to practice, for the first time in Finland, a simultaneous emergency at two plant units.
In 2014, six events warranting a special report were reported by Loviisa NPP. These events did not influence the safety of the employees or the area surrounding the plant. Fortum Power and Heat Oy (hereinafter referred to as “Fortum”) has several pending long-term nuclear safety development projects that involve development of the management system, processing of operational events, as well as maintenance of the operational limits and conditions. STUK will monitor their progress and assess effectiveness of the measures. As part of the oversight of the organisation, STUK ordered a study to assess the nuclear safety culture of Fortum and the functionality of related procedures. The report states that safety is appreciated at Loviisa NPP and the safety culture in general is at an acceptable level. However, the NPP must continue active development of the safety culture.
In 2014, three events warranting a special report were reported by the operating units at Olkiluoto. These events did not influence the safety of the employees or the area surrounding the plant. STUK performed an annual outage inspection in compliance with the inspection programme during the annual outage. Good operations and examples of continuous improvement were observed during the inspection. During inservice inspections carried out during the annual outage, Teollisuuden Voima Oyj (hereinafter “TVO”) detected cracks in the feedwater lines of both plant units. The cracked mixing points will be replaced during the next annual outage. In 2014, STUK focused its regulatory oversight on the plant’s management, modification and procurement processes. A reformed modification work process was introduced in 2014.
At both Olkiluoto and Loviisa, modifications required for improving safety continued regarding plant systems, structures and components as well as operating procedures. An expansion project of the interim storage facility for spent nuclear fuel at Olkiluoto proceeded as planned in 2014. System modifications have been completed. A decision on an application to increase the capacity of the interim storage facility for spent nuclear fuel is being processed by STUK. An upgrade project regarding the reactor coolant pumps, their control and the frequency converters needed to supply power to the pumps has been started at Olkiluoto. STUK approved the project’s conceptual design plans in 2014. As a result of the Fukushima accident, Olkiluoto will improve, for example, systems used to cool the reactor and add whole new systems for pumping water into the reactor in case of a complete loss of AC power. In 2014, a modification of an auxiliary feedwater system recirculation line was implemented at Olkiluoto 1. It reduces the system’s dependence on seawater cooling.
The purpose of an I&C renewal project launched at Loviisa NPP in 2005 was to digitalise almost the entire I&C system of the plant. In 2014, Fortum announced that the supplier of the modernisation had been changed and the scope of the renewal project had been significantly cut back, which is why the project would not be completed until by the end of 2018. Modifications implemented in 2014 included improving reliability of the reactor coolant system’s pressure control system at Loviisa 2 and installing qualified safety valves for the secondary side water and water/steam flow. As a result of the Fukushima accident, four air-cooled heat exchangers have been installed that will ensure cooling of the fuel in the reactor and the fuel pools in case heat transfer to the sea is lost. Furthermore, separate flood protection components have been installed in some systems important to safety. The protection elements take into account exceptionally high seawater levels during a storm.
Most of the detailed design of the Olkiluoto 3 plant unit has been approved by STUK, and the volumes of construction work and component manufacture have decreased. Installation activity at the Olkiluoto 3 construction site has also slowed down starting in early 2014. Manufacture and installation of the emergency diesel generator auxiliary system pipelines were almost the only works still ongoing in 2014. Pressure and leak tightness tests of the containment took place at the nuclear island in February. STUK inspected the plant site before testing and oversaw the testing. Results of the tests clearly met the acceptance criteria. The most important open issue regarding plant design at Olkiluoto 3 is the I&C systems. In 2014, the licensing of I&C proceeded well as STUK approved the overall I&C plan, i.e. architecture, and found that the analysis of I&C active failures were acceptable. Next, STUK started reviewing the technical I&C materials. In 2014, STUK ordered a preliminary report on the safety culture during commissioning of Olkiluoto 3. Challenges highlighted in the report included the highly complex stage during the lifecycle of the plant and the fact that open items and deviations from the construction stage tend to cumulate. Issues that were deemed especially challenging included potential slow processing of unexpected events and people focusing only on their own work in a very narrow sector. The results will assist STUK in targeting its regulatory oversight to the key issues and challenges during the commissioning stage.
In 2014, STUK drafted preliminary safety assessments on supplementary applications for the decisions-in-principle on Fennovoima’s Hanhikivi 1 and TVO’s Olkiluoto 4. In its preliminary safety assessment on Fennovoima’s Hanhikivi 1 plant unit, STUK stated that an AES-2006 nuclear power plant of Rosatom can be constructed in a manner that meets the Finnish safety requirements. However, STUK raised some issues where meeting of the Finnish safety requirements would require changing of the NPP design, such as provisions for an airplane crash, internal floods, fires and severe accidents. STUK also stated that Fennovoima must improve its expertise and develop its management system in order to be capable to assess and ensure the safety of a new NPP, as well as to draft the construction license materials to be submitted to STUK. In its supplementary application, TVO applied for an extension of five years to the deadline for submitting a construction license application for the new nuclear power plant unit at Olkiluoto in compliance with the 2010 decision-in-principle. STUK stated that there are no nuclear safety issues that would prevent the extending of the deadline. The Government approved Fennovoima’s supplementary application for the decision-in-principle and the Parliament ratified it. The Government refused TVO’s application on an extension to the deadline for the construction license application. In 2014, STUK continued its preparations for the processing of the construction license applications.
The processing and storage of nuclear waste and spent nuclear fuel, as well as the nuclear fuel repository project, proceeded safely, and no problems were detected at Loviisa or Olkiluoto. Due to the successful planning of operations, the plants accumulated clearly less nuclear waste than NPPs on average. At Loviisa NPP, STUK supervised the commissioning of a liquid waste solidification facility. Damage was observed in concrete containers used in solidification at the end of 2013. Trial runs were discontinued to study their cause. STUK deemed the conclusions made based on reports correct. Loviisa NPP continued its activities and studies pertaining to the commissioning of the solidification facility, and the trial runs should be completed by the end of 2015. STUK reviewed and approved a periodic safety assessment of the Loviisa low- and intermediate-level operational waste repository and stated that the safety level of the repository is good and its operation can be safely continued. VTT Technical Research Centre of Finland is preparing the decommissioning of a research reactor at Otaniemi. STUK issued statements on the environmental impact assessment program for the decommissioning and a related report.
The project by Posiva Oy (hereinafter referred to as “Posiva”) on final disposal of spent nuclear fuel has proceeded: Posiva submitted a construction license application for the encapsulation plant and disposal facility to the Government in late 2012. Posiva submitted to STUK the safety documentation required by the Nuclear Energy Decree and STUK started reviewing the materials in early 2013. The fact that some of the application materials were submitted to STUK late and the need for additional information to some documents was postponed the review process, which was completed in late 2014. A statement by the Advisory Committee on Nuclear Safety on the Posiva construction license application and the preliminary safety assessment by STUK, as well as STUK’s statement, could not be submitted to the Ministry of Employment and the Economy until in early 2015. The process was very demanding because it was the first preliminary safety assessment for a repository of this type in the world. STUK used a team of Finnish and international experts from a variety of technical sectors as an aid in its review. In addition to reviewing the documents, STUK conducted inspections of Posiva’s management system and organisation. STUK was able to determine that the encapsulation plant and disposal facility can be constructed in such a manner that it will be safe. In separate decisions on documents by virtue of section 35 of the Nuclear Energy Act, STUK presented specific requirements regarding the construction stage. The requirements included supplementing the system design of the encapsulation plant in compliance with the construction stages, further studies on the performance of the barriers of the repository and development of the long-term safety case for the operating license application.
The construction of the underground research facility (Onkalo) was completed for the most part by the end of 2012. In 2014, Posiva excavated facilities to be used to test the final disposal method, as well as the last of the shafts and tunnels, and completed structural engineering works. STUK supervised the construction of the underground research facility, the operations of Posiva’s organisation and the research carried out at Onkalo.
The safeguards of nuclear materials in Finland was implemented in compliance with the international agreements. Annual verifications of design information were implemented for the nuclear power plant units under construction and the physical inventories of nuclear materials of the operating NPPs were verified. STUK verified the correctness of stored fuel data by means of spent fuel measurements. Furthermore, STUK inspected the operations of other nuclear material holders and physical inventory results. As a summary of the inspections and oversight in 2014, STUK could state that nuclear energy was used in compliance with the reports and no unannounced activities took place. Inspection results submitted by the IAEA and the European Commission as well as conclusions made based on the inspection activities also support STUK’s observations. In 2014, the IAEA and the Commission started electronic transfer of surveillance data from Loviisa NPP directly to the Commission and further to the IAEA. Enabling the electronic transfer of monitoring data is an obligation laid down in the Additional Protocol of the Safeguards Agreement between Finland and the IAEA. STUK’s duty was to support the NPPs and international organisations when they ensure that the electronic data transfer complies with all requirements pertaining to nuclear security and information security. In 2014, STUK participated in a laser scanning campaign of the Onkalo facility carried out by the Commission and the IAEA where it was verified that Onkalo has been constructed as reported. The results of the campaign can be used as reference data in future inspections of Onkalo.
In 2014, all Finnish nuclear power plants operated safely and caused no danger to their surrounding environment or employees. The collective radiation doses of employees were yet again historically low and the radioactive releases into the environment very small. The low employee radiation doses were the result of short annual outages and improvements implemented by the NPPs. Radioactive waste generated in the operational processes of the NPPs accumulated as anticipated. Its processing and final disposal in underground facilities took place in a controlled manner. An emergency preparedness drill was arranged at the Loviisa NPP in November to practice, for the first time in Finland, a simultaneous emergency at two plant units.
In 2014, six events warranting a special report were reported by Loviisa NPP. These events did not influence the safety of the employees or the area surrounding the plant. Fortum Power and Heat Oy (hereinafter referred to as “Fortum”) has several pending long-term nuclear safety development projects that involve development of the management system, processing of operational events, as well as maintenance of the operational limits and conditions. STUK will monitor their progress and assess effectiveness of the measures. As part of the oversight of the organisation, STUK ordered a study to assess the nuclear safety culture of Fortum and the functionality of related procedures. The report states that safety is appreciated at Loviisa NPP and the safety culture in general is at an acceptable level. However, the NPP must continue active development of the safety culture.
In 2014, three events warranting a special report were reported by the operating units at Olkiluoto. These events did not influence the safety of the employees or the area surrounding the plant. STUK performed an annual outage inspection in compliance with the inspection programme during the annual outage. Good operations and examples of continuous improvement were observed during the inspection. During inservice inspections carried out during the annual outage, Teollisuuden Voima Oyj (hereinafter “TVO”) detected cracks in the feedwater lines of both plant units. The cracked mixing points will be replaced during the next annual outage. In 2014, STUK focused its regulatory oversight on the plant’s management, modification and procurement processes. A reformed modification work process was introduced in 2014.
At both Olkiluoto and Loviisa, modifications required for improving safety continued regarding plant systems, structures and components as well as operating procedures. An expansion project of the interim storage facility for spent nuclear fuel at Olkiluoto proceeded as planned in 2014. System modifications have been completed. A decision on an application to increase the capacity of the interim storage facility for spent nuclear fuel is being processed by STUK. An upgrade project regarding the reactor coolant pumps, their control and the frequency converters needed to supply power to the pumps has been started at Olkiluoto. STUK approved the project’s conceptual design plans in 2014. As a result of the Fukushima accident, Olkiluoto will improve, for example, systems used to cool the reactor and add whole new systems for pumping water into the reactor in case of a complete loss of AC power. In 2014, a modification of an auxiliary feedwater system recirculation line was implemented at Olkiluoto 1. It reduces the system’s dependence on seawater cooling.
The purpose of an I&C renewal project launched at Loviisa NPP in 2005 was to digitalise almost the entire I&C system of the plant. In 2014, Fortum announced that the supplier of the modernisation had been changed and the scope of the renewal project had been significantly cut back, which is why the project would not be completed until by the end of 2018. Modifications implemented in 2014 included improving reliability of the reactor coolant system’s pressure control system at Loviisa 2 and installing qualified safety valves for the secondary side water and water/steam flow. As a result of the Fukushima accident, four air-cooled heat exchangers have been installed that will ensure cooling of the fuel in the reactor and the fuel pools in case heat transfer to the sea is lost. Furthermore, separate flood protection components have been installed in some systems important to safety. The protection elements take into account exceptionally high seawater levels during a storm.
Most of the detailed design of the Olkiluoto 3 plant unit has been approved by STUK, and the volumes of construction work and component manufacture have decreased. Installation activity at the Olkiluoto 3 construction site has also slowed down starting in early 2014. Manufacture and installation of the emergency diesel generator auxiliary system pipelines were almost the only works still ongoing in 2014. Pressure and leak tightness tests of the containment took place at the nuclear island in February. STUK inspected the plant site before testing and oversaw the testing. Results of the tests clearly met the acceptance criteria. The most important open issue regarding plant design at Olkiluoto 3 is the I&C systems. In 2014, the licensing of I&C proceeded well as STUK approved the overall I&C plan, i.e. architecture, and found that the analysis of I&C active failures were acceptable. Next, STUK started reviewing the technical I&C materials. In 2014, STUK ordered a preliminary report on the safety culture during commissioning of Olkiluoto 3. Challenges highlighted in the report included the highly complex stage during the lifecycle of the plant and the fact that open items and deviations from the construction stage tend to cumulate. Issues that were deemed especially challenging included potential slow processing of unexpected events and people focusing only on their own work in a very narrow sector. The results will assist STUK in targeting its regulatory oversight to the key issues and challenges during the commissioning stage.
In 2014, STUK drafted preliminary safety assessments on supplementary applications for the decisions-in-principle on Fennovoima’s Hanhikivi 1 and TVO’s Olkiluoto 4. In its preliminary safety assessment on Fennovoima’s Hanhikivi 1 plant unit, STUK stated that an AES-2006 nuclear power plant of Rosatom can be constructed in a manner that meets the Finnish safety requirements. However, STUK raised some issues where meeting of the Finnish safety requirements would require changing of the NPP design, such as provisions for an airplane crash, internal floods, fires and severe accidents. STUK also stated that Fennovoima must improve its expertise and develop its management system in order to be capable to assess and ensure the safety of a new NPP, as well as to draft the construction license materials to be submitted to STUK. In its supplementary application, TVO applied for an extension of five years to the deadline for submitting a construction license application for the new nuclear power plant unit at Olkiluoto in compliance with the 2010 decision-in-principle. STUK stated that there are no nuclear safety issues that would prevent the extending of the deadline. The Government approved Fennovoima’s supplementary application for the decision-in-principle and the Parliament ratified it. The Government refused TVO’s application on an extension to the deadline for the construction license application. In 2014, STUK continued its preparations for the processing of the construction license applications.
The processing and storage of nuclear waste and spent nuclear fuel, as well as the nuclear fuel repository project, proceeded safely, and no problems were detected at Loviisa or Olkiluoto. Due to the successful planning of operations, the plants accumulated clearly less nuclear waste than NPPs on average. At Loviisa NPP, STUK supervised the commissioning of a liquid waste solidification facility. Damage was observed in concrete containers used in solidification at the end of 2013. Trial runs were discontinued to study their cause. STUK deemed the conclusions made based on reports correct. Loviisa NPP continued its activities and studies pertaining to the commissioning of the solidification facility, and the trial runs should be completed by the end of 2015. STUK reviewed and approved a periodic safety assessment of the Loviisa low- and intermediate-level operational waste repository and stated that the safety level of the repository is good and its operation can be safely continued. VTT Technical Research Centre of Finland is preparing the decommissioning of a research reactor at Otaniemi. STUK issued statements on the environmental impact assessment program for the decommissioning and a related report.
The project by Posiva Oy (hereinafter referred to as “Posiva”) on final disposal of spent nuclear fuel has proceeded: Posiva submitted a construction license application for the encapsulation plant and disposal facility to the Government in late 2012. Posiva submitted to STUK the safety documentation required by the Nuclear Energy Decree and STUK started reviewing the materials in early 2013. The fact that some of the application materials were submitted to STUK late and the need for additional information to some documents was postponed the review process, which was completed in late 2014. A statement by the Advisory Committee on Nuclear Safety on the Posiva construction license application and the preliminary safety assessment by STUK, as well as STUK’s statement, could not be submitted to the Ministry of Employment and the Economy until in early 2015. The process was very demanding because it was the first preliminary safety assessment for a repository of this type in the world. STUK used a team of Finnish and international experts from a variety of technical sectors as an aid in its review. In addition to reviewing the documents, STUK conducted inspections of Posiva’s management system and organisation. STUK was able to determine that the encapsulation plant and disposal facility can be constructed in such a manner that it will be safe. In separate decisions on documents by virtue of section 35 of the Nuclear Energy Act, STUK presented specific requirements regarding the construction stage. The requirements included supplementing the system design of the encapsulation plant in compliance with the construction stages, further studies on the performance of the barriers of the repository and development of the long-term safety case for the operating license application.
The construction of the underground research facility (Onkalo) was completed for the most part by the end of 2012. In 2014, Posiva excavated facilities to be used to test the final disposal method, as well as the last of the shafts and tunnels, and completed structural engineering works. STUK supervised the construction of the underground research facility, the operations of Posiva’s organisation and the research carried out at Onkalo.
The safeguards of nuclear materials in Finland was implemented in compliance with the international agreements. Annual verifications of design information were implemented for the nuclear power plant units under construction and the physical inventories of nuclear materials of the operating NPPs were verified. STUK verified the correctness of stored fuel data by means of spent fuel measurements. Furthermore, STUK inspected the operations of other nuclear material holders and physical inventory results. As a summary of the inspections and oversight in 2014, STUK could state that nuclear energy was used in compliance with the reports and no unannounced activities took place. Inspection results submitted by the IAEA and the European Commission as well as conclusions made based on the inspection activities also support STUK’s observations. In 2014, the IAEA and the Commission started electronic transfer of surveillance data from Loviisa NPP directly to the Commission and further to the IAEA. Enabling the electronic transfer of monitoring data is an obligation laid down in the Additional Protocol of the Safeguards Agreement between Finland and the IAEA. STUK’s duty was to support the NPPs and international organisations when they ensure that the electronic data transfer complies with all requirements pertaining to nuclear security and information security. In 2014, STUK participated in a laser scanning campaign of the Onkalo facility carried out by the Commission and the IAEA where it was verified that Onkalo has been constructed as reported. The results of the campaign can be used as reference data in future inspections of Onkalo.
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