Miyagawa Kogyo

What Miyagawa Kogyo does

Miyagawa Kogyo (宮川興業株式会社) is a Japanese specialty construction and maintenance services contractor headquartered in Tsuruga, Fukui Prefecture, with approximately 160 employees. The company's core business is providing mechanical maintenance, inspection, decontamination, and cleaning services for nuclear and thermal power generation facilities, with a particular concentration on Kansai Electric Power's Mihama, Takahama, and Ohi nuclear power stations, as well as Japan Atomic Power's Tsuruga plant and Hokuriku Electric Power's Tsuruga thermal plant. Its service scope spans reactor cavity decontamination, heat exchanger inspection, seawater pipe inspection, pump maintenance, fuel handling, controlled-area laundry, and certified personnel dispatch.

The company's technical foundation is its deep roster of certified tradespeople: 4 first-class and 6 second-class radiation handlers, 12 arc welding and 12 stainless steel welding technicians, 30+ oxygen deficiency work supervisors, 50+ oxygen deficiency/H2S work supervisors, and certified pipework construction managers. It operates a precision machining workshop (lathes, drilling machines, plasma cutters) and a fleet of cranes, trucks, and forklifts. The company is ISO9001 certified (continuously since April 2007), registered as Fukui Prefecture construction contractor, and licensed for general worker dispatch. It is a designated direct subcontractor of Kanden Plant (関電興業) and has been part of the Kansai Electric Power Group since June 2024; it will rename to Power Plus Co., Ltd. (株式会社パワープラス) effective April 1, 2026.

Commercially, Miyagawa Kogyo operates an enterprise field-sales model with no public pricing or digital channels; all services are delivered on-site at customer power plants, with offices physically embedded within the premises of each major nuclear facility. Revenue is not publicly disclosed. The value proposition is decades of operating history, embedded site presence, and the cumulative regulatory certifications required to perform qualified nuclear maintenance work — a profile that is operationally stable but geographically and customer-concentrated to Fukui Prefecture and a small set of utility customers.

Name

Miyagawa Kogyo

Legal name

宮川興業株式会社

Website

https://miyagawa-k.jp

Company type

Private

Founded year

1971

Operating status

Operating

Headcount range

101–250 employees

Short description

Miyagawa Kogyo (宮川興業株式会社) is a Japanese specialty maintenance contractor providing mechanical inspection, decontamination, and certified welding services to nuclear and thermal power plants, primarily serving Kansai Electric Power's Fukui-based reactors as a designated direct subcontractor within the Kansai Electric Power Group.

Ownership category

akta.pro rank

Product category

Nuclear and Thermal Power Plant Maintenance Services

NAICS

Nuclear Electric Power Generation (221113)

SIC

Special Industry Machinery (No Metalworking Machinery) (3550)

akta.pro primary industry

Work Management & Field Services (Scheduling, Work Packs, Craft Labor, Scaffolding/Insulation) (EUAKABAI)

akta.pro secondary industries

Performance Improvement & Operational Excellence (INPO/WANO, Human Performance, KPIs) (EUAKABAK), Mechanical, Electrical & Piping Installation (MEP) (EUAKAAAG)

Keywords

• Nuclear plant maintenance
• Mechanical equipment installation
• Pipe work services
• Controlled area decontamination
• Scaffolding civil engineering

Headquarters

HQ city

Tsuruga

HQ country

Japan

HQ region

Asia

Offices5 records

Markets served

GTM type

B2B

Offering type

Services

Cost components

Personnel, Operations, Technology or R&D, Infrastructure, Others

Revenue model

1. Nuclear Power Plant Maintenance Services: Core revenue stream from maintenance, inspection, decontamination, and repair services for nuclear power generation facilities. Includes reactor cavity decontamination, heat exchanger inspection, seawater pipe inspection, pump maintenance, and fuel handling operations for Kansai Electric Power nuclear plants.
2. Construction and Installation Works: Mechanical equipment installation, piping, and civil engineering construction services. Registered as Fukui Prefecture construction contractor (般～3)第3989号.
3. Controlled Area Laundry and Cleaning Services: Decontamination laundry and cleaning services for radiation-controlled areas, including worker clothing and equipment清洗. Includes management area cleaning services.
4. General Worker Dispatch Services: General labor dispatch services (一般労働者派遣事業) providing skilled workers to power plant operations.

Go-to-market motion1 record

Distribution channels1 record

Marketing channels3 records

Core offering

Miyagawa Kogyo is a construction management company that performs installation, pipe work, scaffolding, and civil engineering work, with deep specialization in the maintenance, inspection, cleaning, and decontamination of nuclear and thermal power plants. The company also operates controlled-area laundry services and dispatches qualified workers to support plant operations. Its customer base centers on Japanese electric utility operators and industrial facility owners requiring regulated-environment maintenance support.

Product overview

Miyagawa Kogyo is a construction and engineering services company that provides mechanical equipment installation, pipe work, and civil engineering services. The company's primary focus is on comprehensive maintenance, inspection, cleaning, and decontamination services for nuclear power plants operated by Kansai Electric Power (関西電力). Services include reactor cavity decontamination, heat exchanger maintenance, fuel handling, water pipe inspection, and laundry services for contaminated work clothes within controlled areas. The company also provides certified personnel dispatch services through its general worker dispatch business. The company operates branches at three nuclear power plant sites (Mihama, Takahama, and Ohi) and is part of the Kansai Electric Power Group.

Differentiator

Problem solved

Functional benefit

Products and services

• Nuclear power plant maintenance, inspection, cleaning, and decontamination Inspection, cleaning, and decontamination of nuclear power plant systems and controlled areas for electric utility operators; performed by certified technicians in regulated environments.
• Mechanical equipment installation Installation of mechanical equipment at power plants and industrial facilities for utility operators and industrial plant owners.
• Pipe work services Piping fabrication and installation for power plants and industrial facilities, supporting process and utility piping requirements.
• Scaffolding and civil engineering Erection of scaffolding and civil engineering support for power plant and industrial construction and maintenance projects.
• Controlled-area laundry services Laundry handling for protective clothing and linens used in controlled and radioactive areas at nuclear facilities, provided to utility operators.
• Worker dispatch services Dispatch of qualified technicians and craft workers (mechanical, piping, scaffolding, civil) to power plants and industrial sites for project-based assignments.

Quantifiable outcome

• Serves all major nuclear units at Mihama (1-3), Takahama (1-4), and Ohi (1-4) reactors for Kansai Electric Power
• +1 more outcomes

Named customers6 records

Segments3 records

Ideal customer profiles2 records

Technology focussed No

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature4 records

Partnerships

Six partnerships are on record, tiered core, historical and minor.

• Kanden Plant Co., Ltd. (関電プラン卜株式会社)coreStrategic or Co-development Partner · 1 June 2024In June 2024, Miyagawa Kogyo transferred shares to Kanden Plant and Kanden Power Tech (関電パワーテック), becoming part of the Kansai Electric Power Group. Kanden Plant serves as the parent company with a direct subcontractor relationship for nuclear facility maintenance operations.
• Atox Corporation (株式会社アクトックス)historicalStrategic or Co-development Partner · 1 September 2021In September 2021, Miyagawa Kogyo's shares were transferred to Atox Corporation. This was a prior parent company relationship before the company joined the Kansai Electric Power Group.
• Kansai Electric Power Group (関西電力グループ)coreStrategic or Co-development Partner · 1 April 1969Miyagawa Kogyo has operated as a designated direct subcontractor (直属協力会社) of Kansai Electric Power's subsidiary Kanden Plant since the establishment of the Mihama branch in April 1971. The company formally joined the Kansai Electric Power Group through share transfer in June 2024.
• Kansai Electric Power Co., Ltd. (関西電力株式会社)coreStrategic or Co-development PartnerPrimary customer and ultimate parent company. Miyagawa Kogyo has provided maintenance services to Kansai Electric Power's Mihama, Takahama, and Ohi nuclear power stations for over 50 years.
• Japan Atomic Power Company (日本原子力発電株式会社)minorStrategic or Co-development PartnerProvides maintenance and fuel handling services to the Tsuruga Nuclear Power Station Unit 2.
• Hokuriku Electric Power Company (北路電力株式会社)minorStrategic or Co-development PartnerThermal power station operations and maintenance services through Hokuriku Power Engineering (北陸発電工事).

Scale indicators5 records

Recent moves7 records

Expansion highlights8 records

Broad incumbents

• Hitachi-GE Nuclear Energy, Ltd. Leading Japanese nuclear plant equipment manufacturer and lifecycle services provider, including plant maintenance and outage support. Competes with Miyagawa for higher-value engineering scopes and sets the technical standard for reactor maintenance services across the Japanese fleet.
• Kandenko Co., Ltd. (株式会社関電工): Major electrical and mechanical construction contractor affiliated with the KEPCO Group. Operates broadly across electrical infrastructure including nuclear and thermal power plant construction and maintenance — overlapping with Miyagawa's MEP/scaffolding scope but at much larger scale and broader geographic reach.
• Mitsubishi Heavy Industries, Ltd. Major nuclear steam supply system (NSSS) manufacturer and comprehensive plant services provider for Japanese reactors. Competes for high-value maintenance, modernization, and decommissioning scopes that overlap with Miyagawa's specialized services, though at much broader portfolio scale.

Direct peers

• Kanden Power Tech Co., Ltd. (関電パワーテック株式会社): Sister company inside the KEPCO Group and co-acquirer of Miyagawa. Performs power plant maintenance, fuel handling, and decommissioning support for KEPCO nuclear plants. Directly comparable in service scope, customer relationship structure, and nuclear specialization.
• Sanki Engineering Co., Ltd. (三機工業株式会社): Japanese mechanical and electrical facility engineering firm providing HVAC, plumbing, and plant maintenance services for industrial facilities including nuclear power stations. Comparable in handling radiation-controlled-area mechanical work and certified personnel deployment.
• Atox Corporation (株式会社アトックス): Former parent of Miyagawa Kogyo (until June 2024). Specialized nuclear facility decontamination, decommissioning, and waste management services firm with strong KEPCO/utility relationships. Operates in the same regulatory niche and competes for similar maintenance scopes.
• Kanden Plant Co., Ltd. (関電プラント株式会社): Direct parent company of Miyagawa Kogyo within the Kansai Electric Power Group. Provides specialized maintenance, construction, and facility management for KEPCO's nuclear and thermal power plants — the same core service line as Miyagawa, with overlapping customer base across the same Fukui-based nuclear assets.

Emerging players

• Japan Atomic Power Company (日本原子力発電株式会社): While primarily a nuclear plant operator (one of Miyagawa's customers at Tsuruga), JAP also performs in-house maintenance and engineering for its own fleet. Comparable in nuclear operations specialization but structured as a utility rather than a service contractor.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat5 records

Key risks7 records

Key highlights7 records

Customer concentration

Compliance2 records

Revenue estimate

Valuation estimate

Number of profiles

Funding overview

Funding rounds

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about Miyagawa Kogyo