RENEWAL OF THE YVL GUIDES AND THEIR IMPLEMENTATION TO
OPERATING NUCLEAR POWER PLANTS
MARJA-LEENA JÄRVINEN
Radiation and Nuclear Safety Authority (STUK)
Helsinki
Finland
Abstract
The Finnish detailed nuclear safety requirements for the use of nuclear energy are presented in
the YVL Guides issued by Radiation and Nuclear Safety Authority (STUK). The comprehensive
renewal of the YVL Guides was lanced in 2006 and the renewed set of YVL Guides was published in 2013. Especially EU directives, IAEA safety requirements, harmonized EN-IEC standards as well as WENRA Reference Levels and Safety objectives for new reactors are used when
preparing regulatory guides. In addition to the these international references licensing and construction of the Olkiluto 3 experience and the lessons learned from the Tepco Fukushima Daiichi accident in 2011 were taken into account in the renewal process. The requirements in the
YVL Guides are set to a new nuclear facility. Separate decisions on the application of the YVL
Guides to operating nuclear facilities are made by STUK. The implementation of the renewed set
of YVL Guides is presented with some examples of safety improvements to operating nuclear
power plants.
1. INTRODUCTION
The Finnish framework of regulations for the use of nuclear energy consists of the Nuclear Energy Act, Nuclear Energy Decree, the four government Decrees on safety, physical protection,
emergency preparedness and the on the safety of the disposal of nuclear waste. Detailed safety
regulations (YVL Guides) are issued by STUK based on Section 7 r of the Nuclear Energy Act.
These Guides are binding regulations for the licensees, while preserving the licensee's right to
propose an alternative procedure or solution to that provided in the regulations. If the licensee
can convincingly demonstrate that the proposed procedure or solution will implement safety
standards in accordance with the Nuclear Energy Act, STUK may approve the procedure or solution by which the safety level set forth is achieved.
The first YVL Guides were issues in early 1970’s. The set of YVL Guides has evolved within
the established structure of eight topical areas during 1970 – 2013 based on the needs so that the
number of issued YVL Guides was 71 at the end of 2012. In 2006 STUK made a decision on the
comprehensive renewal of the YVL Guides.
The requirements in the YVL Guides are set to a new nuclear facility. Separate decisions on the
application of the YVL Guides to operating nuclear facilities are made by STUK.
2. THE COMPREHENSIVE RENEWAL OF YVL GUIDES
The renewal of the YVL Guides was launched in 2006. The goal of the renewal was to get more
user friendly, consistent guidance to the stakeholders. Operating experience, research, development of technology and international safety standards are taken into account in the preparation of
regulations. Especially EU directives, IAEA safety requirements, harmonized EN-IEC standards
as well as WENRA Reference Levels and Safety objectives for new reactors are used when preparing regulatory guides. In addition to the these international references licensing and construc-
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tion of the Olkiluoto 3 experience and the lessons learned from the Tepco Fukushima Dai-ichi
accident in 2011 were taken into account in the renewal process.
Special consideration has been paid to such issues as the limitation of the releases in a severe
accident, practical elimination concept, defense-in-depth concept and the independence of the
DiD levels, diversification of the ultimate heat sink, ensuring the residual heat removal in station
black out, external events and extreme weather conditions, seismic events and the safety and
security interface.
At the beginning of the project the four Government Decrees defining the safety requirements on
safety, security, emergency preparedness and waste management were updated in 2008. As a
consequence of the lessons learned from the Tepco Fukushima Dai-ichi accident in 2011 the
Government Decrees on Safety of the Nuclear Power Plants and the Government Decree on the
Emergency Preparedness needed to be updated before issuing the new renewed set of YVL
Guides. The updated Government Decrees on these areas were issued in October 2013.
Stakeholders’ involvement to the development of the YVL Guides was enhanced. At the beginning of the YVL Guide renewal project a new form of the stakeholder involvement was established. For each of YVL Guides a reference group composed of experts from stakeholder organizations was established. In addition a reference group for the overall renewal of the regulations
and guides was established. These groups help to take into account stakeholders’ feedback more
efficiently in a timely manner in the preparation.
3. NEW SET OF YVL GUIDES
The YVL Guides have been continuously improved. The major steps in the safety level required
by the Finnish regulations and YVL Guides are related to the nuclear power plant accidents as
follows:



TMI: small LOCA and severe accidents
Chernobyl: reactivity accidents, severe accident management, safety culture
Tepco Fukushima Dai-ichi: enhancement of the protection against external hazards, accident management and emergency preparedness
In the renewal process also the overall organization of the YVL Guides was considered. After
thorough discussion it was decided to organize the YVL Guides into five topical areas. The new
set of YVL Guides is organized into five series of guides (Fig. 1):
A.
B.
C.
D.
E.
Safety management of the use of nuclear energy
Plant and systems design
Radiation safety of a nuclear facility and environment
Nuclear materials and waste
Structures and equipment of a nuclear facility
The consistency of the YVL Guides was verified by internal and external reviews. The reviews
made during the preparation process include the coverage of YVL Guides related to the IAEA
safety requirements as well as WENRA Reference Levels 2008 and Safety objectives for the
new reactors.
The revised set of YVL Guides covering safety, security and safeguards has been published in
2013 (Figure 1). The changes due to lessons learned from the Fukushima Daiichi accident have
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been included in the new set of YVL Guides. At the end of 2014 only two guides wait for publication due to the needed chances in the legislation or upper level regulations. The change of the
Nuclear Energy Act has been signed by the president in May 2015. Thus YVL C.7 related to the
environmental monitoring of the nuclear facilities is to be published at the end of 2015 and the
YVL D.6 is to be published after issuing the mandatory requirements related to uranium and
thorium mining and milling.
A Comprehensive internal and external training on new guides has been arranged. The YVL
Guides are available at STUKLEX and at STUK web site in Finnish and in English. The translation into Swedish has been started.
Figure 1. The renewed set of YVL Guides published in 2013.
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4. THE IMPLEMENTATION OF THE YVL GUIDES TO OPERATING NUCLEAR FACILITIES
The YVL Guides were published at the end of the year 2013. They are applied as such for new
nuclear facilities. For the existing facilities and facilities under construction separate facility specific implementation decisions are made.
In the Government Decree there are transition provision related to the exemption of the requirements and application of the Nuclear Energy Act 7 a § which states that
Guiding principles
The safety of nuclear energy use shall be maintained at as high a level as practically possible. For the further development of safety, measures shall be implemented
that can be considered justified considering operating experience and safety research and advances in science and technology.
STUK made the decision on the hearing the licensees on the application of the new YVL Guides
to the nuclear facility in question. The licensees have given their assessment on the compliance
with the new YVL Guides at the end of the year 2014. In case of non-compliances the licensees
are expected to make proposal of the safety improvements at the nuclear facility.
STUK has established its own review and assessment project to prepare decision on the application of the new YVL Guides to operating nuclear facilities. Each of the licensees receives licensee and facility specific decisions on all of the 45 YVL Guides. The approved exceptions and
their justifications are stored in the STUK’s requirements management tool. This tool can be
utilized in the future on the planning of the inspections, for review and assessment, for licensing
and periodic safety review. The major licensing activities at the Finnish nuclear facilities are
shown in Figure 2. New methodology is expected to enhance the consistency of the regulatory
decisions.
Figure 2. The major licensing activities at the nuclear facilities in Finland during 2012 – 2023.
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At the time of the IAEA Technical Meeting on the Safety Challenges for New Nuclear Power
Plants the STUK decisions are under preparation. In the presentation some examples of the safety improvements at Loviisa 1 and Loviisa 2 as well as Olkiluoto 1 and Olkiluoto 2 nuclear power
plants are given.
5. REFERENCES
[1] Government Decree on the Safety of Nuclear Power Plants (717/2013)
[2] Government Decree on the Security in the Use of Nuclear Energy (734/2008)
[3] Government Decree on Emergency Arrangements at Nuclear Power Plants (716/2013)
[4] Government Decree on the Safety of Disposal of Nuclear Waste (736/2008)
[5] RADIATION AND NUCLEAR SAFETY AUTHORITY, YVL B.1 Safety design of a nuclear power plant, Helsinki (2013)
[6] INTERNATIONAL ATOMIC ENERGY AGENCY, Safety of Nuclear Power Plants: Design, Series No. SSR-2/1, Vienna(2012)
[7] INTERNATIONAL ATOMIC ENERGY AGENCY, Safety of Nuclear Power Plants: Design, Series No. SSR-2/1, DS456
[8] WESTERN EUROPEAN NUCLEAR REGULATORS’ ASSOCIATION, WENRA Reactor
Safety Reference Levels, (2008)
[9] WESTERN EUROPEAN NUCLEAR REGULATORS’ ASSOCIATION, WENRA Statement
on Safety Objectives for New power Reactors (2010)
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