Guidance for the

Application of the Safety Case and Safety Assessment Methodology Using SAFRAN Tool for the Waste Retrieval from Historical RADON-type Facilities

Draft Guidance No. 1

2014-07-25

CONTENTS

1. INTRODUCTION ......

Background ......

Objective ......

Scope ......

2. DEMONSTRATING THE SAFETY STATUS OF RADON FACILITIES

Historical waste.

Legacy objects.

RADON-type facilities.

3.SAFETY REQUIREMENTS AND NATIONAL REGULATIONS

Requirements for the safety case and safety assessment ......

Assessment of existing regulations relevant to legacy problems based on GSR Part 5, BSS and Russian Regulatory documents

4.THE SAFETY CASE FOR THE MANAGEMENT OF RADIOACTIVE WASTE AT RADON-TYPE FACILITIES (ON THE BASE OF MURMANSK RADON)......

Role and development of the safety case ......

Components of the safety case ......

Interacting processes ......

Application of SAFRAN for SC for Murmansk RADON (Anisimov)

5. SAFETY ASSESSMENT FOR RADON-TYPE FACILITIES (ON THE BASE OF MURMANSK RADON).

Introduction ......

Overall approach ......

Assessment context ......

Description of the facility or activity and of the waste......

Development and justification of scenarios ......

Formulation and implementation of assessment models

Performance of calculations and analysis of results. . . . .

Analysis of assessment results ......

Analysis of SAFRAN assessment outcome (Anisimov)

6. SPECIFIC ISSUES ......

Optimisation

Graded approach ......

Defence in depth ......

Reliability ......

Expected Time for Activity Implementation ......

Remediation (IAEA and Russian documents)

REFERENCES . . .

ANNEX I: SAFETY CASE AND SAFETY ASSESSMENT OF MURMANSKFOR THE WASTE RETRIEVAL FROM HISTORICAL RADON-TYPE RADON FACILITY (Anisimov)

CONTRIBUTORS TO DRAFTING AND REVIEW ......

1. INTRODUCTION

1.1. Background

There are many old historical disposal facilities that were simple (without engineered barriers) or were primitivelyengineered, with a soil cover of typically only a few meters over the waste. Thewaste was often disposed of without treatment or conditioning and with verysimple waste acceptance criteria (WAC) or sometimes with no criteria. Somespecific facilities of this type are described in greater detail in Refs [1–4].

Some of the early established disposal facilities do not meet current safetyrequirements, and the disposed waste packages do not meet modern wastepackage quality standards. Safety assessments and environmental measurementshave demonstrated that some of these repositories may represent anunacceptable risk or hazard to the environment, workers and the public,therefore requiring remediation actions.

Similarly, some old interim storage facilities contain waste and wastecontainers that have deteriorated, or the general storage conditions no longermeet the requirements for safety. Again, this indicates a need for remediationof the facilities. In some cases, inadequate waste storage practices continue tobe applied, due to:

a)A lack of appropriate knowledge and practical experience in radioactive waste management in general;

b)A lack of appropriate technologies for waste processing (treatment and conditioning);

c)A lack of well defined requirements for waste quality and acceptance criteria for long term storage or disposal;

d)Inadequate storage or disposal conditions, and unacceptable impact of external conditions on waste and waste packages;

e)Poor quality of waste forms, waste containers or other engineered barriers;

f)Storage or disposal of waste in its original form and without appropriate packaging.

The concepts and requirements for safe storage and disposal haveevolved over time. There is now a general international consensus that low andintermediate level waste (LILW) can and should be safely stored and disposedof in properly designed and licensed engineered facilities with site specific andpackage specific WAC [5, 6].

A decision to retrieve radioactive waste from some old storage ordisposal facilities could be made if the present status of safety and security doesnot correspond to current standards or requirements, or if the existing social,political or economic situation requires such remediation actions. The cost ofwaste retrieval and facility or site remediation — both in terms of radiationexposure and financial expenditures resulting from the remediation — isnormally justified by the improved safety and security of the facility or siteafter remediation, the availability of the facility or site for other purposes, etc.In all steps of waste retrieval and site remediation, safety of the staff, protectionof the environment and waste security should be given the highest priorities.

Several countries have initiated or already completed the upgrading ofold repositories or storage facilities for radioactive waste, or they are facing thenecessity to take appropriate actions. Analysis of the existing experience inplanning, implementation and management of such projects is important forimproving the efficiency of relevant waste retrieval, reconditioning and siteremediation in Member States. A review of the available information on thissubject, along with a discussion of related problems and existing practices,would be of particular benefit to Member States facing retrieval andreconditioning projects but that are lacking corresponding experience.

The problems associated with retrieval of solid waste differ significantlyfrom those associated with retrieval of liquid waste and disused sealed sources.In order to adequately cover all of the different aspects, the IAEA isdeveloping separate documents for each of these waste types. This report dealsspecifically with the retrieval and reconditioning of solid waste. The aspects ofretrieving old fluidizable or ‘wet waste’ and the retrieval and management ofdisused sealed radioactive sources are covered in other IAEA publications[7–10].

A common challenge for all historical waste types is the assessment ofexisting documentation, which is addressed in Ref. [11]. A comprehensiveunderstanding of the retrieval and reconditioning of different types of oldwaste may be obtained from Refs [7–11].

1.2. Reasons for retrieval of waste

There are a number of reasons why waste in legacy storage and disposalfacilities may require retrieval and reconditioning. These include:

a)Safety reasons:

  1. Discovery or recognition of a real or potential problem that could lead to undesirable safety, environmental or radiological impacts (e.g. leaching of contaminants into groundwater or impending structural failure of the facility);
  2. Insufficient or lack of waste inventory data, where there may be particular or potential concern justifying actions (e.g. significant uncertainty over the quantity of long lived radionuclides in a facility designed for short lived waste);
  3. Degradation of waste packages or facility structures in a way that may compromise the current or future safety of the facility;
  4. Waste forms not performing as predicted by previous safety analyses;
  5. Implementation of a conditioning programme for waste that was previously stored in an unconditioned state.

b)Technical and financial reasons:

  1. A desire to reduce the volume of stored or disposed waste (e.g. torecover space to create further storage or disposal capacity andextend the life of an existing storage facility that is at or nearcapacity);
  2. A desire to consolidate several smaller facilities into a larger one;
  3. As a precursor to the decommissioning of a storage facility;
  4. Retrieval of material previously considered to be waste but nowconsidered to be useful.

c)Legislative and public perception reasons:

  1. Changes in regulations (e.g. to impose additional constraints thatretroactively apply to existing facilities);
  2. An order from a regulatory body or other government agency (e.g. toconform to a new national standard or to meet government policy);
  3. A policy decision or other requirement to extend the storage periodbeyond that originally considered (e.g. beyond the design life of theoriginal facility or waste packages);
  4. Lack of public acceptance of an existing facility and a subsequentadministrative decision for its closure.

1.3. RADON-type facilities

RADON-type facilities are varied in nature, size and complexity, and have different hazards associated with them, both from normal operation and from accidents. The magnitude and content of the radioactive inventory is also varied. Furthermore, a RADON-type storage facility could be one of several facilities on a site and may be independent from the other facilities, may be connected to other facilities or may be an integral part of a larger facility. Commensurately, the extent and complexity of the safety case and supporting safety assessment will differ according to the facility or activity, and will also evolve through its lifetime (e.g. construction, commissioning, operation). In view of these considerations, a graded approach is required to be applied to the development and review of the safety case and supporting safety assessment [3]. The recommendations contained in this Guidance are comprehensive and sufficient for the most complex and hazardous facilities. Their use in a graded manner is intended to be illustrated in a number of Safety Reports to be developed to cover a range of facilities.

1.4. Safety case as a safety argument for decision making

The safety case is the collection of scientific, technical, administrative and managerial arguments and evidence in support of the safety of a waste management facility or activity, covering the suitability of the site and location and the design, construction and operation of the facility, the assessment of radiation risks and assurance of the adequacy and quality of all of the safety related work associated with the facility or activity. Safety assessment, an integral and important part of the safety case, is driven by a systematic assessment of radiation hazards. The latter involves quantification of radiation dose and radiation risks that may arise from the facility or activity for comparison with dose and risk criteria, and provides an understanding of the behaviour of the facility or activity under normal conditions and anticipated operational occurrences and in the event of accidents. The safety case and supporting safety assessment provide the basis for demonstration of safety and for licensing. They evolve with the development of the facility or activity, and assist and guide decisions on each step of the facility life cycle taking into account previous stages. The safety case also is the main basis on which dialogue with interested parties is conducted and on which confidence in the safety of the facility or activity is to be developed.

1.5. Objective

The objective of this Guidance is to provide recommendations for development and review of the safety case and supporting safety assessment for the waste retrieval operations from historical RADON-type facilities. It summarizes the most important considerations in assessing and demonstrating the safety of facilities and activities, and documents the steps that should be followed in developing the safety case and performing the safety assessment.

1.6. Scope

The Guidance is addressed to operators, regulatory bodies and supporting technical specialists developing or reviewing the safety case and supporting safety assessment for the waste retrieval operations from historical RADON-type facilities. It covers all aspects of the safety case and safety assessment, including the use of a graded approach and SAFRAN Tool.

The Guidance provides recommendations on a systematic methodology for evaluation of the adequacy and acceptability of waste management arrangements and the radiological impacts on workers, the public and the environment from planned waste retrieval activities and from accidents at a historical RADON-type facility or in a related activity.

2. DEMONSTRATING THE SAFETY STATUS OF RADON-TYPE FACILITIES

2.1. The IAEA established an international intercomparison and harmonization project on the subject called the International Safety Assessment Driving Radioactive Waste Management Solutions (SADRWMS). This project has contributed significantly to the development of an international consensus on the methodology for demonstration and assessment of safety, and to the content of this Guidance.

The safety assessment conducted in support of the safety case should employ a systematic methodology to demonstrate compliance with the applicable safety requirements. Criteria should be developed to be met at the various stages of the lifetime of the facility, and these criteria should include the periodic review of the safety case and supporting assessment. This should help ensure that interested parties are confident in the safety of the facility or activity. Once developed by the operator, the safety case is reviewed by the regulatory body to verify compliance with relevant safety requirements and criteria.

2.2. Historical waste.

In general “Historical wastes” are those that are generated without a complete traceable characterization programme or quality management system in place.

Key characteristics of historical wastes are:

— may be conditioned, partially treated, or raw;

— poor or no information/traceability;

— cannot conclusively identify originating process/location; and,

— waste streams may be mixed.

The primary identifiers of historical wastes are:

— incomplete history;

— incomplete or improper characterization/treatment; and

— quality system does not cover the whole life cycle at the time of generation or does not meet the modern standards for the whole life cycle.

Many countries (e.g. the USA, Russian Federation, UK, the former USSR republics, Eastern European States, China) currently have historical radioactive waste inside storage or disposal facilities designed and constructed a long time ago. In the Russian Federation radioactive waste generated before entry into force of the Federal Law On Management of Radioactive Waste and Amendment to some Acts of Law of the Russian federation (July 6, 2011) are called as “accumulated radioactive waste”. They should be included into radioactive waste register according to the procedure established by this Federal Law. Accumulated radioactive waste classified as retrievable radioactive waste shall be retrieved, processed, conditioned and disposed of.

2.3. Legacy objects.

Past development of commercial and military uses of radioactive material led to the development of many nuclear facilities worldwide. In many countries, these facilities were built and operated before the regulatory infrastructure was in place to ensure that they were effectively decommissioned at the end of their useful life. The legacy from this build up is that many countries now have abandoned nuclear facilities or areas where spills or accidents have occurred that are contaminated with long-lived radioactive and toxic residues that pose substantial environmental and health concerns.

Due to historic activities typically related to radium industry, uranium mining, and military programs, there are numerous sites that contain or are contaminated with radioactivity. Several member states have identified legacy facilities and sites.Historic disposal facilities can also be identified as legacy objects.

Some disposal facilities have never been licensed for disposal; those that have been licensed some time ago are often now non-compliant with internationally accepted principles and even national safety standards. Due to such non-compliance some historic facilities are now licensed for storage while they were sited, constructed and operated as disposal facilities and waste retrieval wasn’t considered in design and face with serious problems in practical realization. In some cases unfavourable conditions inside some stores have caused corrosion and degradation of waste packages. In many cases, inadequate storage conditions have resulted in disappearance of original markings, labels, and signs that could help identify the origin and characteristics of the waste. In many cases due to influence of environmental factors after decades of operation engineered barriers degrades more and faster than it was supposed in 1960-s. Accumulation of water within the vaults is often identified and according to radionuclide content and specific activity this water can often be classified as liquid radioactive waste. In some cases radionuclides migrates into nearfield.

2.4. RADON-type facilities.

The RADON system was established in the former Soviet Union in early 60-s of the XX century for collecting, transportation, processing and near surface disposal of low and intermediate level institutional radioactive waste. There were 35 special combines located in most cases close to regional scientific centers and covering all territory of the country. Two largest RADON special combines were located close to Moscow and St. Petersburg (former Leningrad). Near surface RADON facilities were sited, designed, constructed and operated as disposal facilities according to typical design based on the knowledge level of that time. In most cases RADON facility is a trench in the clayey rock about 4 meters depth where rectangular construction is erected from reinforced concrete and covered from above with concrete slabs equipped with the loading hatches. It can be subdivided into several sections with wooden or concrete walls. It supposed unconditioned waste in packs for easier handling to be emplaced into each section in bulk. In some cases so called RADON technology of combined disposal of solid and liquid waste was implemented and solid waste inside each section were included into cement matrix prepared using low level liquid waste layer after layer (about 1m each).

Typicaldesignof regional RADON facility except of Moscow and Leningrad includesthreenearsurfacedisposalunitsof 200m3eachand 200m3undergroundtankfromstainlesssteelfortemporarystorageofliquidwaste. After 20 yearsofoperationadditional vaults for conditioned solid waste were constructed almost at each RADON site. New reinforced concrete vaults had temporary hangars to protect waste against precipitation during operational phase and had bigger volume up to 960m3. Similar facilities were established in some Eastern European countries. Similardisposalunitsabout the same time were constructed and used within some nuclear fuel cycle facilities. Due to similarity of construction and use of such disposal units and facilities they often are called RADON-type facilities.

3. SAFETY REQUIREMENTS AND NATIONAL REGULATIONS

3.1. This section lists the fundamental safety principles and the main requirements that have to be met when preparing the safety case and supporting safety assessment for a predisposal waste management facility or activity.

REQUIREMENTS FOR THE SAFETY CASE AND SAFETY ASSESSMENT

3.2. The following paragraphs set out the main requirements in Refs [2, 3] that are relevant for the preparation, updating and maintenance and use of the safety case and supporting safety assessment. Recommendations on meeting other requirements in Refs [2, 3] are provided in later sections of this Guidance. For remediation situations, the requirements established in Ref. [13] are applicable.

3.3. Based on the Fundamental Safety Principles (Fundamental Safety Principles, IAEA Safety Standards Series No. SF-1, IAEA, Vienna, 2006) the following safety requirements should be addressed:

—-The operator shall prepare a safety case and a supporting safety assessment. In the case of a step by step development, or in the event of modification of the facility or activity, the safety case and its supporting safety assessment shall be reviewed and updated as necessary;