Ignalina: Decommissioning Chernobyl’s Big Sister

This is a web supplement to "Riding Off into the Sunset: Nuclear Decontamination and Decommissioning Update," appearing in the July 2015 issue of POWER.

The Ignalina Nuclear Power Plant (INPP) is located in eastern Lithuania near Visaginas-a town of more than 20,000 people founded in the mid-1970s for workers constructing INPP and for the purpose of supporting the plant. INPP (Figure 1) operated two RBMK-1500 water-cooled graphite-moderated channel-type power reactors-the same reactor type as was installed at the Chernobyl Nuclear Power Plant, although that plant had four 1,000-MW reactors.

1. The Ignalina Nuclear Power Plant (INPP). During its most productive year, the dual-unit facility located in eastern Lithuania supplied more than 88% of the country's total electricity demand. Courtesy: SE Ignalina NPP

Following the Chernobyl accident in 1986, plans for additional units at INPP were scrapped, even though Unit 3 was estimated to be about 60% complete. The two finished units were allowed to operate, albeit at a reduced thermal power output (roughly 87.5% of the original design capacity).

International Pressure Forces a Decision

During the process of preparing for accession to the European Union (EU) and North Atlantic Treaty Organization (NATO), and at the urging of the international community, the Lithuanian government agreed to retire INPP. Unit 1 was permanently shut down in December 2004 and Unit 2 was removed from service in December 2009. As part of the agreement, the EU is funding a portion of INPP's decommissioning costs.

SE INPP Director General Darius JanuleviAius (Figure 2) told POWER that INPP developed a preliminary decommissioning plan that considered three dismantling strategy options: immediate dismantling, deferred dismantling and safe enclosure, and entombment. In February 2001, under the auspices of the International Atomic Energy Agency (IAEA) project "Support for Decommissioning of Ignalina NPP Unit 1," IAEA experts prepared a report in which the immediate dismantling method was recommended.

2. INPP Director General Darius JanuleviAius. The Minister of Energy appointed JanuleviAius to his current position on March 4, 2013. Courtesy: SE Ignalina NPP

The report stated that regardless of the decommissioning strategy chosen, the process of dismantling Unit 1 would not affect the safe operation of Unit 2, and the entire decommissioning process would adhere to the INPP organizational model. As a result, on November 26, 2002, the Lithuanian government adopted a resolution to decommission Unit 1 by means of immediate dismantling in order to ensure that the process did not lead to serious social, economic, financial, and environmental consequences.

Utilizing Valuable Staff Experience

INPP representatives supported the option because it promised a higher level of employment than other methods. Although some experienced power plant decommissioning specialists would be needed, the INPP staff could be used to perform much of the decommissioning work, which had been one of the plant's top priorities.

Between 2001 and 2004, the final decommissioning plan (FDP) was prepared by INPP and approved by the Lithuanian Ministry of Economy. (The Ministry of Economy coordinated the INPP decommissioning until 2009. Since that time, the Ministry of Energy has taken over the responsibility.) The FDP is now in its seventh edition, having been most recently approved by the Minister of Energy on August 25, 2014. The latest version includes amendments reflecting experience gained by the enterprise.

JanuleviAius suggested that there are several advantages of using the immediate dismantling strategy. He said that using the existing workforce has provided a big benefit because the staff has extensive knowledge of the facility. No other graphite-moderated reactor of such capacity has ever been decommissioned, so there isn't a lot of outside experience to rely on.

The ability to use existing plant infrastructure has also been an advantage, mitigating additional costs that could have been incurred for equipment preservation and extended maintenance. Some other benefits that JanuleviAius noted include having a defined regulatory framework, better cost definition, and no legacy to future generations.

Proceeding with immediate dismantling also has its drawbacks, however. Among them is that the costs associated with decommissioning must be incurred much sooner, there are higher radiation levels, and there isn't the necessary infrastructure for radioactive waste management immediately available.

At least some of the INPP staff envisions parlaying this experience into future projects. The entire process is helping many of them become experts on safe and efficient nuclear facility decommissioning and radioactive waste management. The unique knowledge obtained through the decommissioning of an RBMK-type reactor could very likely be systematized and applied to other nuclear energy projects. In this way, the immediate dismantling strategy is presenting an opportunity both for the enterprise and its highly qualified specialists.

The Path Forward

As in all decommissioning projects, radioactive waste management is a big piece of the pie. At INPP, four major radioactive waste management projects will be completed. The Interim Spent Fuel Storage Facility (ISFSF, Figures 3, 4, and 5) and the Solid Radioactive Waste Management and Storage Facility (SWMSF) are both under way. The other two-the Very-Low-Level Waste Landfill Facility (VLLWLF) and the Near-Surface Repository-are still in the design stage. The plant also has an operating Buffer Storage for Landfill Facility.

3. Interim spent fuel storage facility (ISFSF). Casks are stored in the central hall of the ISFSF. Courtesy: SE Ignalina NPP

4. Heavy load. Moving casks requires special rail car transporters designed for the weight. Courtesy: SE Ignalina NPP

5. Safe placement of casks is important. This overhead view was taken during cold trials conducted in the ISFSF. Courtesy: SE Ignalina NPP

Because the ISFSF is still under construction, the spent fuel cannot be removed from the units yet. The core of Unit 1 has been defueled, but spent fuel remains in both units' pools and in the Unit 2 reactor core. For that reason, INPP is still considered to be in the initial stage of decommissioning.

Dismantling work started on Unit 1 in 2010. Some progress has been made in the removal of the heat station, emergency core cooling system, gas circuit and ventilation system, no-longer-needed safety-related equipment in INPP Unit 1 Building V1, and in the turbine hall (Figures 6, 7, and 8).

6. INPP Unit 2 turbine hall. Tarps and plastic covers help maintain cleanliness while work is in progress to disassemble various pieces of equipment throughout the facility. Courtesy: Saulius DamuleviAius

7. INPP Unit 2 reactor hall. Little dismantling work can be done on the Unit 2 reactor until fuel is removed from the core, which isn't expected to occur until 2019. Courtesy: Saulius DamuleviAius

8. Cutting it down to size. A worker makes a cut on part of the dismantled turbine. Courtesy: SE Ignalina NPP

A new free release measurement facility has been in use at the site since August 16, 2010 (Figures 9 and 10). The facility is equipped with the tools needed to measure the radioactivity of materials so that those not exceeding free release criteria can be disposed of, or reused, without applying radioactive safety requirements. This is a more cost effective solution when removing noncontaminated plant materials, while still being environmentally responsible. The facility is expected to process and release about 110,000 tons of material by the time decommissioning is finished. INPP says that since 2010, it has dismantled 24,700 tons of the 131,000 tons of equipment estimated to be on site (Figure 11).

9. INPP free release measurement facility. Releasing noncontaminated material for conventional disposal or recycling is more cost effective than treating it as contaminated waste. Courtesy: SE Ignalina NPP

10. Free to release? Following decontamination, workers perform a measuring procedure on dismantled parts from the Unit 1 turbine hall. Courtesy: Saulius DamuleviAius

11. INPP radioactive waste cementation facility. A worker views the crane and barrels being used as part of the radioactive waste disposal process. Courtesy: Saulius DamuleviAius

Key decommissioning milestones and the estimated year of completion include:

• ISFSF construction and commissioning completed (2017)
• SWMSF construction and commissioning completed (2018)
• VLLWLF commissioning completed (2018)
• Unit 2 reactor defueling completed (2019)
• Near-Surface Repository commissioning completed (2020)
• Units 1 and 2 spent fuel storage pools defueling completed (2022)
• Units 1 and 2 reactors R1, R2 zones dismantling completed (2027)
• Units 1 and 2 reactors R3 zones dismantling and decontaminating completed (2034)
• Unrestricted release of reactor areas (2036)
• Site restoration completed (2038)

Lessons Learned at INPP

Staffing was a key factor when implementing the immediate dismantling strategy. INPP remains the main employer in the local region by a wide margin. Although plant operators have some of the essential knowledge needed for decommissioning, retraining is still necessary for the project to be successful. In addition, developing a strategy in advance to assign departments or personnel to perform particular activities or provide particular services has proven to be helpful in order to retain in-house know-how and the benefit of past experience.

INPP also believes it is important to learn from and adopt proven solutions. The plant had been using spent fuel casks since 2000. Even so, an effort to innovate to a large-cask concept resulted in a complex licensing process, and the bigger size and weight caused engineering challenges. In some cases, the proven solution could be the best option and reinvention should be avoided.

Establishing a specialized group to liaise with regulators proved to be beneficial for INPP. JanuleviAius suggested that decommissioning is not the same as operation, and should not be treated as such. In some cases, being proactive with regulators, keeping them informed, and providing needed input can benefit all stakeholders.

Consideration must also be given to the effect that limited resources can have on a project. Even though major investments may have been made in waste management facilities, it may not be possible to operate them without sufficient funding. This fact must be communicated to stakeholders and regulators to ensure all entities understand the commitments necessary to see a project through to completion.

Processing radioactive waste locally has proven to be very beneficial for the facility. At INPP, all radioactive waste will be removed to disposal or interim storage facilities that are constructed, or are planned for construction, at the site. This decreases public concern over the risks associated with the location of final storage facilities. INPP transports radioactive waste using special procedures, and under the control of radiation protection specialists, using only INPP roads or railways (public roads are not used for the transportation of radioactive waste).

The total amount of waste that was generated during the operation of INPP, or that will be generated during decommissioning, will remain in the vicinity of the plant. Although this option may not be feasible, or even desirable, for all retiring nuclear plants, it has helped to minimize public concern about the INPP decommissioning project.

With the immediate dismantling strategy, radiation dose is a larger concern than it is when utilizing other options. Although robotic equipment is not currently being used at INPP, plant personnel do follow dose reduction techniques based on the ALARA (as low as reasonably achievable) principle. The main practices utilized for dose reduction are:

• Increasing the distance to the source of ionizing radiation.
• Reducing employee working time in increased radiation dose fields.
• Using biological shielding.

Challenges

One of INPP's biggest challenges so far has been ensuring sufficient funding for the entire decommissioning project. One fear is that if sufficient funding is not available, it could force a revision of the FDP, resulting in possible postponement or cancelation of final decommissioning terms. The risk of not being able to operate, or being only partially able to operate, new radioactive waste management and storage facilities could place the long-term viability of the project in jeopardy.

JanuleviAius said that sufficient and uninterrupted funding would become even more important after 2020, when reactor dismantling is planned to commence following the defueling of the reactors and spent fuel pools. He suggested that it would be impossible to ensure environmental and personnel safety if reactor dismantling had to be disrupted during the process.

Another significant challenge is that there is no proven international practice for treating irradiated graphite; new technologies must be developed. For this reason, INPP's current plan is to dismantle the reactor and to place irradiated graphite in storage until a final treatment and storage solution is developed.

The time it takes to complete decommissioning also poses a challenge. INPP expects the process to last more than 30 years. Detailed planning for a project of such scale is very difficult. Moreover, some technological unknowns add risk and uncertainty to the outcome.

Improving Efficiency

INPP's project management strategy has changed several times since the start of decommissioning, resulting in disconnects between departments and goals. JanuleviAius said that there has been a weak understanding about the interconnection of departmental objectives. There had been a longstanding mindset at the plant that developed through years of operation in which each department guarded its resources to some extent and exchange between departments was not a regular occurrence. Changing that culture has been a challenge, but the projects management department is now working closely with plant technicians to obtain better results for projects implementation.

In accordance with European Commission requirements designed to enhance project efficiency, "make or buy" analysis has been conducted by the enterprise since 2014. Analyses are focused on comparing market prices to the cost of utilizing in-house capacities for services and work not related to nuclear safety. The "make or buy" strategy is expected to allow budget reductions for certain activities, increasing the efficiency of activities and usage of funds. The strategy is at odds with INPP's trade union desires, but JanuleviAius acknowledges that it is often very difficult to satisfy both sides.

The estimated total cost of INPP's decommissioning as presented in the latest version of the FDP is a2.5926 billion (with no escalation and no risks included). This amount includes funding by both the EU and the Republic of Lithuania. From the start of decommissioning through 2013, EU financial support for the project was a1.1 billion, with additional support of a450 million foreseen to cover the period of 2014-2020.

Looking into the INPP Crystal Ball

There is obviously a lot of work to be done during the next 20 plus years, but INPP expects to achieve a brownfield status by 2038. The expectation is for all active residues from the entire plant to be disposed of or stored on the INPP site. The main goal of the decommissioning is to dismantle the majority of INPP buildings and structures using conventional methods, that is, as a non-nuclear energy unit, within a reasonable period of time. By the end of the decommissioning, only facilities that guarantee safe interim storage of treated radioactive waste, its storage at repositories, and interim storage of spent fuel will remain on site.

"The ultimate goal of the decommissioning is to ensure that the site can be used without restrictions or as prescribed by law after the facilities are decontaminated and dismantled, operational waste is managed, the site is cleared and other essential actions are performed," JanuleviAius said. "Upon the completion of dismantling and decontamination at the INPP site, as prescribed by law, the final radiological research will be carried out in order to validate the compliance of buildings and structures with free-release standards."

-Aaron Larson is a POWER associate editor.

The post Ignalina: Decommissioning Chernobyl's Big Sister appeared first on POWER Magazine.