ECCS Strainer & GSI-191 Solutions
Comprehensive solutions for Emergency Core Cooling System performance and regulatory compliance
The Challenge
Following a loss-of-coolant accident (LOCA), debris generated from damaged insulation and coatings can challenge Emergency Core Cooling System (ECCS) strainer performance. Generic Safety Issue 191 (GSI-191) requires nuclear plants to demonstrate that post-LOCA debris will not prevent safety systems from providing long-term core cooling. Plants must manage debris sources, optimize strainer performance, and maintain defense-in-depth while ensuring regulatory compliance.
Our Comprehensive Approach
Moeller Nuclear delivers integrated solutions that address every aspect of ECCS strainer performance and GSI-191 compliance. Our multidisciplinary team combines engineering analysis, field implementation, and operational expertise to optimize sump performance while maintaining safety margins. We transform compliance challenges into opportunities for improved plant reliability and reduced maintenance burden.
Debris Source Reduction
Systematic identification and mitigation of fibrous insulation, particulate, and coating debris sources through engineered replacement programs and zone of influence optimization.
Strainer Enhancement
Advanced strainer designs and modifications that maximize surface area, optimize flow distribution, and minimize head loss across the full spectrum of debris loading conditions.
Performance Validation
Comprehensive testing and analysis programs that demonstrate strainer performance, validate analytical models, and provide margin assessment for regulatory submissions.
Technical Solutions
Fiber Mitigation Programs
- Fibrous insulation removal and replacement strategies
- Low-density fiberglass to RMI conversions
- Encapsulation systems for existing insulation
- Sacrificial strainer area calculations
Strainer Modifications
- Increased strainer surface area designs
- Advanced perforated plate configurations
- Vortex suppression and flow optimization
- Active and passive debris interceptors
Analytical Services
- CFD modeling of containment flow patterns
- Debris transport and settlement analysis
- Head loss correlation development
- Chemical effects evaluation
GSI-191 Compliance Strategy
Deterministic Analysis
Conservative evaluations demonstrating adequate ECCS and containment spray system performance under worst-case debris loading scenarios.
Risk-Informed Approach
Probabilistic assessments that credit realistic debris generation, transport phenomena, and operator actions to demonstrate acceptable risk profiles.
Testing Programs
Design and execution of scaled testing to validate strainer performance, including thin-bed effects, chemical precipitation, and downstream impacts.
Implementation Services
- Containment walkdowns and debris source inventory
- Zone of influence refinement and CAD modeling
- Insulation changeout project management
- Strainer installation and modification oversight
- Coating assessment and remediation programs
- Temporary filtration and mitigation strategies
- Procedure development and operator training
Proven Results
Debris Reduction
Achieve 70-90% reduction in problematic fiber sources through strategic insulation replacement and optimized protection schemes.
Performance Margin
Demonstrate 200-300% available NPSH margin through integrated strainer optimization and debris source management.
Regulatory Success
100% NRC acceptance rate for GSI-191 closure strategies developed and implemented by our team.
Advanced Capabilities
In-Vessel Effects
Evaluation of downstream effects including fuel assembly blockage, core flow distribution, and long-term cooling adequacy.
Chemical Modeling
WCAP-16530 methodology implementation for chemical precipitate formation and head loss impact assessment.
Containment Analysis
Integrated containment response evaluations considering debris effects on heat removal and pressure suppression.
Quality & Compliance
All ECCS strainer solutions conform to:
- 10 CFR 50.46 ECCS acceptance criteria
- Regulatory Guide 1.82 Rev. 4 guidance
- NEI 04-07 methodology and SE requirements
- WCAP-16406-P-A evaluation methodology
- NRC staff review guidance for GSI-191
Ensure ECCS Reliability
Partner with our experts to optimize strainer performance and achieve GSI-191 compliance.
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