Category Archives: Infrastructure and methodologies for the. justification of nuclear power programmes

Development and application of deterministic safety assessment

First, we must ask the question: ‘Why are nuclear reactors hazardous, and in exactly what way are they hazardous?’ The answer to this question (Meneley, 1999) should underlie the rationale for all analysis of potential failures and the means for mitigating those hazards.

10.3.1 Hazards of solid fuel reactors

A typical fuel pellet made of sintered uranium dioxide (melting point approximately 2800°C) is shown in Fig. 10.5. Millions of such pellets are located in an operating power reactor. Almost all the reaction products of fission — fission products — are trapped inside this pellet. The second impor­tant fact is that most of the heat energy of the fission process is produced inside this same pellet. Heat is removed by flowing coolant (usually high — pressure water).

It is apparent that either increasing the rate of heat production (i. e. increasing the rate of fission) or decreasing the rate of heat removal (i. e. decreasing local water pressure or flow) threatens to increase the tempera­ture of the fuel pellet and therefore bring it closer to melting temperature. If and when the pellet melts it will release essentially all of its fission prod­ucts that are volatile at the mixture temperature — some of which are highly radioactive. These fission products represent the main hazard of nuclear reactor operation.


10.5 Typical nuclear fuel pellets.

High-pressure water presents an obvious hazard due to the possibility that a pipe might break and release the water, and so might lead to over­heating of the fuel pellets, if emergency water supply were not available. Other initiating events that reduce the heat removal rate (e. g. loss of forced circulation) add similar hazards.

Returning to the fission process itself, and recalling that the process involves a chain reaction, sheds light on yet another hazard of fission reac­tors. We all know that a chain reaction involving successive generation of fissions is at the heart of this technology. We also know that a few (less than 1% of the total) of the next-generation neutrons essential to keep the chain reaction going at a constant rate are emitted after a slight delay. This is known as the ‘delayed neutron fraction’. Further, to increase reactor power we must manipulate controls so that the number of neutrons in each suc­cessive generation is slightly larger than the number in the previous genera­tion. It is important to control this increasing neutron population to a very low rate so that engineered control systems can return the excess number of neutrons per generation to zero once again, when the desired neutron density (proportional to the reactor power level) is reached.

A serious hazard may arise if and when the excess number of neutrons in successive generations approaches or even exceeds the number of delayed neutrons in that generation; in such a case the rate of multiplication becomes very much faster. If this number exceeds the delayed neutron fraction, the dominant rate of power increase becomes inversely proportional to the time between successive fissions, and the delayed neutrons are left behind. This is known as the ‘prompt critical’ state. Different reactors have different characteristic times; they range between about 1 millisecond in a thermal neutron reactor design to less than a microsecond in a fast neutron reactor. In every case of abnormal operation when a ‘prompt critical’ state can occur it is vital to ensure that either inherent characteristics or highly reliable engineered systems will act to return the reactor to a non-self-sustaining condition — that condition is known as the ‘shut down’ state.

Generic action items

This important classification of significant events is meant to serve as infor­mation (usually regulatory issues) on which action must be taken, either design, analysis, and/or research and development — to resolve outstanding newly identified issues that arise in operation. These issues are resolved, normally, through collaborative work between members of the plant owners groups. They are reviewed, analyzed, and eventually disposed by the national regulatory staff.

Public protection at nuclear power plants (NPPs): controlling discharges into the environment

The radiation protection of the public at NPPs is governed by the undertakings in the Joint Convention and by the requirements in the BSS.

International guidance is available for the regulatory control of radioac­tive discharges to the environment (IAEA, 2000e) and for the environmen­tal and NPPs for purposes of radiation protection (IAEA, 2005a).

In short, the public affected by NPP operations is protected by the control of discharges of radionuclides to the environment. International standards provide regulatory bodies with a structured approach to the limitation of such discharges from NPP operations and optimization of protection from such operations, which may be adapted to the specific legal and regulatory infrastructure within which such a body operates. They also give guidance on the responsibilities of operating organizations in conducting radioactive discharge operations.

Past experience demostrates that operational discharges are low and radiation exposure to the public from NPP operations has been minute. Figure 11.2 has shown how effective the regulatory instruments for limiting discharges from NPPs into the environment have been.

However, there is always the possibility, however remote, that a massive release of radioactive materials into the environment occurs as a result of a catastrophic accident. This is what happened as a result of the Chernobyl accident, a controversial topic that will close this chapter.

Statute of the IAEA

In April 1955, work had began on drafting the Statute of the IAEA with the participation of governmental representatives from Australia, Belgium, Canada, France, Portugal, South Africa, the UK, and the US. Later, in early 1956, the group expanded to include representatives from Brazil, the former Czechoslovakia, India, and the USSR. These historical events have been summarized in IAEA (1997b).

As well described by Fischer (2003), the IAEA’s founders held the view that there were three primary functions for the new Agency, namely:

1. To promote the peaceful use of nuclear energy throughout the world

2. To ensure that any nuclear plant, activity or information it works with, is used only for peaceful purposes

3. To ensure the safe use of any such plant, activity or information.

This perspective took root during the development of the IAEA Statute, which was formally approved on 23 October 1956 by the Conference on the Statute of the IAEA, held at the Headquarters of the UN.[23] Eighty-one nations voted unanimously to approve the IAEA Statute. Thereafter, the IAEA Statute entered into force 29 July 1957, by which time 26 States had deposited their instruments of ratification. Thus, the IAEA was established as an autonomous organization, independent of the UN through its own international treaty, the IAEA Statute; however, the IAEA reports to both the UN General Assembly and the UN Security Council.[24] In this regard, the IAEA’s relationship with the UN is regulated by special agreement dated 30 October 1959 (reproduced in INFCIRC/11) (IAEA, 1959). Organizationally, the IAEA comprises a Secretariat, headed by a Director General, together with two policy-making bodies: the 35-member Board of Governors and the General Conference which consists of all Member States.

On 29 July 2007, the IAEA officially turned 50. During the interim years, its Statute has been amended several times.[25]

Management of low — and intermediate-level waste

14.5.1 Overview

Contrary to spent nuclear fuel and high-level waste, there is no need to put LLW and ILW in interim storage for heat decay. This waste can be disposed of directly after it has been conditioned and packaged if a disposal facility is available. Some buffer storage is, however, normally built at the reactor site. The steps for management of LLW/ILW are shown in Fig. 14.11. The first step is normally performed at the power plant and results in a package that is clean on the outside and can be further handled in the subsequent steps. In some cases also, centralized treatment and conditioning facilities have been erected, e. g. for incineration or melting of low-level waste.

A central principle for the management of LLW and ILW is waste mini­mization in both activity and volume by appropriate design measures and operating and decommissioning practices. A key component is the selection and control of materials used in the nuclear power plant or during


14.11 Steps for management of LLW/ILW.

maintenance. Bringing unnecessary material into the radiologically control­led zone should in particular be avoided as this might later be declared as radioactive waste. It is further recommended to segregate the waste pro­duced at the source to avoid cross-contamination of low-active material with material with higher activity. Other methods for waste minimization are decontamination of the waste for recycling to the extent possible and economically justified and compaction and/or incineration of compactable and combustible waste.

Public perception of nuclear power

The social impacts of a nuclear power choice need to be accepted by the main stakeholders and by public opinion, even if this means allowing the expression of opposition to the policy and, moreover, even if the full meaning of that ‘acceptance’ is unknown. It needs to be underlined that many people have no real concerns about this topic, except those living near sites, so there is often a ‘passive acceptance’ among the public at large. It must also be observed that public opinion is very complex, sometimes con­tradictory or paradoxical or ambivalent about nuclear power, and it is impossible to have a clear understanding of this complexity using only quantitative polls (see below). In any case, there is little ‘spontaneous’ public perception of nuclear power, except memories of Chernobyl and (since 2011) of Fukushima, and a general link to the atomic bomb, which seems to imply a structural negative image. Beyond this, opinions are built by the media, by political leaders, by a country’s political history and its international context, and they can evolve, as is shown by the Swedish case (where there was a referendum with options to phase out the nuclear pro­gramme in 1980, but opinion polls in favour of moving to a nuclear pro­gramme in 2005, as the international context was increasingly in favour of nuclear power). It is the responsibility of government to give sufficient and honest information on energy to explain and justify the nuclear choice.

An impressive fact, observed everywhere in the world, is that a country’s public opinion is more in favour of nuclear energy if a nuclear programme already exists there; similarly, people living in the neighbourhood of nuclear plants are more in favour of nuclear power than the general public.

Nuclear power (and energy in general) is not one of the main concerns of the public at large, except when there is an energy crisis, such as increas­ing energy prices, or blackouts of supply, or oil spills. All quantitative surveys at a national or international level (for example, the Eurobarometer

Special Report on Energy Technologies (European Commission, 2007a), or the IRSN — Institut pour la Radioprotection et la Surete Nucleaire — Barometer on perception of risks (IRSN, 2006)) show that social, health and security issues are spontaneously cited as people’s main concerns (see Tables 16.2 and 16.3).

It must be observed that, in most surveys, when a question about informa­tion on energy is raised, the majority of people (about 70%) say that they

Table 16.2 Responses to the question ‘What are the most important issues facing your country today?’

Issue %

Unemployment 64

Crime 36

Healthcare system 33

Economic situation 30

Immigration 29

Pensions 28

Inflation 26

Education system 19

Terrorism 19

Taxation 19

Housing 15

Energy prices and shortages 14

Environmental protection 12

Public transport 6

Defence and foreign affairs 5

Table 16.3 Responses to the question ‘In your opinion, which two of the following should be given priority in your government’s energy policy?’

Issue %

Guaranteeing low prices for consumers 45

Guaranteeing a continuous supply of energy 35

Protecting the environment 29

Protecting public health 22

Guaranteeing your country independence in the field 18

of energy

Reducing energy consumption 15

Fighting global warminga 13

Guaranteeing the competitiveness of your country’s 7


a Global warming is more and more considered as an important issue but many people still don’t know the link between nuclear energy and limiting climate change.

don’t have sufficient information about it. However, when public debates are organized, few people from the general public participate in the meet­ings except those in the neighbourhood of nuclear sites.

We should here consider a number of methodological issues to help us understand public perception of nuclear power. There are many quantita­tive opinion polls, realized at both a national and an international level, which are very useful to measure a population’s degree of knowledge and concern. Eurobarometers, realized under the aegis of the European Commission, are well known and often taken as a reference tool. Such Eurobarometers have addressed different topics regarding nuclear energy: Europeans and Nuclear Safety Report (2007b), Energy Technologies: Knowledge, Perception, Measures (2007a) and Radioactive Waste (2005). The main results of these polls are discussed below, but it is important first to note several limitations of this kind of tool. First, most of the questions raised are closed questions: sometimes the wording doesn’t have the same sense for all respondents, and may even be very far from the respondents’ concerns. Second, it is worth noting that there are significant differences between European countries, so it is impossible to speak about something like ‘European public opinion’ regarding nuclear power.

To complement quantitative approaches, qualitative studies (in-depth analyses of people’s opinions by non-directive interviews, open questions, etc.) are also useful to have a sound understanding of people’s representa­tions, in all their complex and sometimes paradoxical or contradictory aspects. Such a qualitative approach is necessary in order to be aware of all obstacles to nuclear acceptance. For instance, a qualitative study under­taken in France in 2005, before the passing of a new Act on waste manage­ment, showed that the public at large were not ready to accept the idea of long-term geological disposal, one of the reference solutions for managing HLLL radioactive waste, because the time-scales involved in waste man­agement (for some categories of waste being as long as a million years) seemed to be, from a philosophical point of view, beyond human responsi­bility. The appropriate answer was of course not to avoid such a solution in the new Act, but to take into account people’s expectations of the reversibil­ity of disposal. The 2006 Act on Sustainable Management of Radioactive Materials and Radioactive Waste requires that any geological disposal be reversible for a minimum of 100 years.

Taking another example, many quantitative polls ask simple questions but phrase them in terms which are not those used by the public in everyday life, or which are difficult to interpret. When discussing nuclear power, ques­tions that are too simple are not relevant. For example, the simple question ‘Are you against or in favour of nuclear power?’ does not take into account or explain that, in several countries, about 50% of the public have no precise opinion on nuclear power, or have ambivalent perceptions, with some people thinking that ‘it is good for the economy and bad for the environ­ment’ whilst others think the opposite.

It is also difficult to interpret answers to closed questions such as ‘Do you agree/disagree with the following opinion: waste disposal may be imple­mented in safe conditions’, because we do not know what each of the dif­ferent respondents consider to be ‘safe conditions’. The same can be said about the following question asked in the EU Waste Eurobarometer: ‘Would you be more in favour of nuclear energy if one would have solved the problem of waste management?’, which requires an understanding of what is meant, to the public at large, by having ‘solutions’ for the problem of waste management; we know that technical solutions already exist but their social acceptance remains problematic.

It therefore seems appropriate to combine quantitative and qualitative approaches: the quantitative approach to have a rough vision of the accept­ance and evolution of public opinion, and the qualitative approach to acquire an understanding of people’s concerns.

Overlap with other regulatory controls

An effective regulatory system will need to be able to coordinate the activi­ties of the different authorities. It will be important to clearly demarcate their competences in order to reduce areas of overlap, and to design systems which encourage cooperation between regulators when necessary. In the UK, there is a split between health and safety controls, which are adminis­tered through site licences regulated by the HSE (ND) under the Nuclear Installations Act 1965 and the Ionising Radiations Regulations 1999, and environmental controls, which are predominantly overseen by the EA. In order to ‘avoid duplication of effort and potentially conflicting demands as between radioactive substances regulations and those matters for which HSE is responsible’ (Tromans, 2010, p. 295), the EA and the HSE entered into a Memorandum of Understanding in 2002 with the objectives (para­graph 6) of facilitating effective and consistent regulation by ensuring that:

(i) activities of EA and HSE in relation to nuclear licensed sites are consistent, coordinated and comprehensive;

(ii) the possibility of conflicting requirements being placed on licensees, or others operating on nuclear sites. . . is avoided;

(iii) synergies are exploited and the appropriate balance of precautions is attained;

(iv) duplication of activity is minimised; and

(v) public confidence in the regulatory system is maintained.

The Schedule to the Memorandum sets out the joint working arrangements between the EA and the HSE, in an effort to provide clarity to both the regulators and the regulated. There are various other interfaces of regula­tory control (e. g. safety and security, transport) which will need to be care­fully considered in the context of nuclear plant, and a similar level of coordination will be required.

17.2 Conclusions

As the European Commission has recently identified, one of the objections to SEA and EIA is that their benefits cannot be easily measured in financial or monetary terms. Nonetheless, there are a great number of benefits that arise from the SEA and EIA, and the benefits of carrying out the processes should be seen to outweigh the financial implications of preparing the assessment documentation. EIA and SEA bring benefits to any regulatory system which aims to establish harmonisation between the planning process and environmental integrity. This is fundamental in the context of nuclear energy as these considerations will be crucial in ensuring that energy policy is met with a degree of public approval. Not only do SEA and EIA ensure that environmental considerations are taken into account as early as pos­sible in the decision-making process, they are ensure ‘more transparency in environmental decision-making and, consequently, social acceptance’ (European Commission, 2009, paragraph 2.4).

It will be equally important to consider how the planning and regulatory processes can be used to assess and control environmental impacts. Environmental considerations play a pervasive role in both processes, and will need to be carefully controlled. Planning systems should be designed so that the environmental risks can be sufficiently scrutinised. States will need to develop legal systems which adequately reflect the intended balance of powers, and which provide the government with residual influence and control over certain key decisions. The regulatory system will need to be reinforced by a sanctioning regime which is stringent enough to compel compliance. Although the UK approach is instructive, other jurisdictions will ultimately need to determine for themselves what role the environment will play in shaping the future of nuclear power generation. The various examples of other established civil nuclear states, multinational regulations

and practices, international conventions and IAEA standards are also valu­able sources for emerging civil nuclear states.

17.3 Future trends

In April 2010, the European Union Committee of the Regions published an Opinion entitled ‘Improving the EIA and SEA Directives’ (European Union Committee of the Regions, 2010). Besides affirming the importance of the SEA Directive and EIA Directive as tools in environmental protec­tion, the Committee recognised that certain gaps remain in ensuring that the processes realise their objectives. Perhaps unsurprisingly, one of the main proposals of the Committee is that the EIA Directive should be amended so as to incorporate thresholds, criteria or triggers for the pur­poses of determining the significance of environmental impacts caused by Annex II activities. The Committee highlights the fact that certain Member States, when implementing the EIA Directive, have been shown to exceed their powers of discretion by only taking account of certain Annex III selec­tion criteria or by completely exempting certain types of project in advance. The Committee also makes recommendations that the assessment of alter­native solutions should be made obligatory, and that gaps in public partici­pation procedures should be addressed by giving the public early and effective opportunities to participate from the earliest possible point. The Committee makes few concrete recommendations in relation to the SEA Directive, principally by virtue of the fact that further experience in apply­ing the SEA Directive is required. However, certain issues are identified, notably that a specific definition of reasonable alternatives on a mandatory basis should be developed, that it should be made obligatory to establish methods and indicators of monitoring environmental impacts, and that the SEA Directive should better identify what information the Environmental Report should contain.

The coalition government in the UK has decided to abolish the IPC and replace it with the MPIU, but decisions will still be taken in accordance with NPSs. The UK remains committed to new nuclear power despite the serious events which occurred at the Fukushima nuclear plant in Japan. With a number of major new build planning applications in the pipeline, it will be interesting to assess how the UK balances environmental impacts with other factors such as energy security and climate change. There will no doubt be considerable environmental opposition, and any favourable deci­sions will be potentially subject to legal challenge.

Division of responsibility tables

A practical way of specifying the division of responsibilities (DOR) among project participants is to present it in table form, with a row for each scope item, listed as per the IAEA Account System (IAEA, 2000), for example. Depending on the contract approach selected by the owner, this can be done for the complete plant, separately for each of the main packages in a split-package contract, or for each of the main packages or items in a multi­package (i. e. ‘by components’ contract approach).

Table columns with specific headings allow allocation of responsibilities to the different project participants, who are designated by initials or acro­nyms indicated in the table layout (e. g. owner (o), plant/package supplier (s), civil works supplier (cv)). Following is a list of typical column headings to allocate the scope of supply and responsibilities:

• Input data

• Conceptual design

• Basic design

• Detail design

• Equipment procurement and supply

• Construction (civil works and erection)

• Testing and commissioning.

A last column entitled ‘Remarks’ provides space to include notes and clari­fications to the responsibility allocation, when required.

End of life and requests for decommissioning

Decommissioning begins to be addressed at an early stage of a nuclear power plant programme. As noted in Table 20.3, the Safety Analysis Report includes a decommissioning concept including provisions for safety, the differing approaches to decommissioning, and planning of work. The end state for decommissioning, depending on national legal and regulatory requirements, encompasses partial or full decontamination and/or disman­tlement, with or without restrictions on further use of the site. The IAEA has developed basic safety requirements that must be satisfied during the planning and implementation of decommissioning, for the termination of practices and for the release of facilities from regulatory control (IAEA, 2006a). Chapter 24 describes the various aspects of decommissioning and the experience already gained.

There are three general approaches that could be followed to achieve a decommissioning end state. In all three cases, a facility is eventually released for other uses, either with or without regulatory restrictions, but the time frames are different. The first approach is immediate dismantlement, where radioactive contaminants are removed or reduced to a level that permits the facility to be released. For this approach, the decommissioning project would need to be initiated shortly after the end of plant operations. It requires timely completion of the decommissioning site activity and removal of radioactive material from the NPP to a licensed facility, followed by processing for either long-term storage or disposal. The second approach is deferred dismantling or safe storage. In this case, any SSCs that have radio­active contaminants are either processed or placed in a condition where they can be safely stored and maintained. Subsequently, the SSCs are decontaminated and/or dismantled such that the facility’s radioactivity returns to levels that allow the facility to be released. The third approach is entombment. For this approach, the radioactive SSCs are safely encased until the radioactivity decays to a level such that the facility can be released from regulatory control.

Whatever approach is taken, the licensee must ultimately develop a final decommissioning plan for regulatory approval. The development of this information will likely require a preliminary period of work before the decommissioning plan can be finalized and be submitted to the regulator. The plan might encompass the strategy, the current state of the plant includ­ing radiological characteristics, the schedule, implementation and manage­ment of the plan, how the waste will be managed, and a description of the end state and how it will be verified.

The licensing submission will also require a safety assessment that may include some of the topics in Table 20.2. The assessment would cover the decommissioning activities given in the plan and any potential abnormal events that could occur. The occupational exposures and the potential releases to the environment, and the health and safety of the public, would be addressed, including the mitigation and prevention strategies. The IAEA recommendations for the development and review of the decommissioning safety assessments are given in a Safety Guide (IAEA, 2009b), where it is stated:

Decommissioning activities are performed with an optimized approach to achieving a progressive and systematic reduction in radiological hazards, and are undertaken on the basis of planning and assessment to ensure the safety of workers and the public and protection of the environment, both during and after decommissioning operations.

The site can be released from regulatory control once the licensee has completed the decommissioning work and has met the regulatory require­ments. Recommendations for meeting these requirements are the subject of an IAEA Safety Guide (IAEA, 2006b). The Guide is directed to both the regulatory body and the licensee, and covers the release of sites or parts of sites from regulatory control after a practice has been terminated.

The need for human resources in nuclear power programmes

F. J. SANCHEZ, Tecnatom, Spain

Abstract: Human reliability is directly related to the competencies of the personnel. A cornerstone of a new nuclear programme is to have available, on time, enough professionals with the necessary competencies.

This chapter will help readers foresee the need for human resources, which organizations are involved, which specialities will be more demanding, the relevance of the educational system and different strategies to cope with the lack of vocations, the changing in the specialization requirements in the nuclear power plant (NPP) lifecycle, the international effort to support such challenges and some key considerations to design and implement effective initial and continuing training programmes.

Key words: human resources, competencies, knowledge management, education and training.

6.1 Introduction

Within the justification concept, safety and reliability are two cornerstone issues. In both, human reliability is always implicit. This important factor, human reliability, is directly related to the competencies of the personnel.

The International Atomic Energy Agency (IAEA, 2009a) defines ‘com­petencies’ as a ‘combination of knowledge, skills and attitudes in a particu­lar field, which, when acquired, allows a person to perform a job or task to identified standards. Competencies are developed through a combination of education, experience and training.’

No new nuclear programme will succeed if not enough personnel, having suitable competencies, are allocated on time to accomplish their duties with full responsibility. In the nuclear renaissance, solving this problem could constitute a bottle neck as important as competing for a slot in a vessel head forge or even more.

This chapter will help readers foresee the need for human resources, which organizations are involved, which specialities will be more demand­ing, the relevance of the educational system and different strategies to cope with the lack of vocations, the changing in the specialization requirements in the nuclear power plant (NPP) lifecycle, the international effort to support such challenges, and some key considerations in designing and implementing effective initial and continuing training programmes.

The relevance of developing strategic human resources planning at an earlier stage of the project, and the specific factors to take into considera­tion when planning, are addressed in Section 6.2. The core of the section reveals the appropriate staffing of the different nuclear stakeholders to carry out their mission. Among the nuclear stakeholders are included the human resources requirements of political decision makers, regulatory authorities, educational and training organizations, research centres, utili­ties, engineering and service companies, main suppliers and equipment vendors, construction companies, plant operators, nuclear fuel cycle and waste management companies.

Section 6.3 focuses on the nuclear education programmes, including the research and development (R&D) projects as a natural source to create new nuclear knowledge, the support provided by the national educational system, including the universities and the vocational schools, and strategies to enhance the education system to attract new vocations. Finally, national initiatives in different countries to promote nuclear knowledge are introduced.

The importance of knowledge management is discussed in Section 6.4 in connection with the changes of specialization requirements throughout the NPP lifecycle. The study is conducted in four different stages: engineering and licensing, construction and commissioning, plant operation, and decom­missioning, where according to the different tasks and activities to be under­taken, the corresponding level of education and speciality for professionals, technicians and craftsmen is identified.

The benefit of international collaboration is the starting point for Section 6.5. The relevance of the Institute of Nuclear Power Operation (INPO) as a reference for personnel training and qualifications, the common education and training efforts at the level of the International Atomic Energy Agency (IAEA) or EURATOM FP-7 among others, and the international networks of excellence in education and training are the topics covered in this section.

Section 6.6 describes the main features to design effective initial and sustained training programmes based on the international standard of the Systematic Approach to Training (SAT). An important part of the section is devoted to discovering the elements to create a comprehensive training system, such as training regulatory requirements, training organization, management and staffing, training programmes and materials, instructors and training facilities and training tools, including simulators. In conclusion, the section suggests that training as a strategic tool for human performance improvement be taken into consideration.

Sources of further information, including important specialized websites, and the references used in this chapter are included in Sections 6.7 and 6.8 respectively.