{
    "title": "Hydrophobic Cement",
    "inventor_name": null,
    "publication_year": 2014,
    "device_name": "Hydrophobic Cement Mixture",
    "goal": "Prevent highly contaminated radioactive water from leaking into the sea by creating an impermeable barrier in trench walls.",
    "problem_addressed": "Leakage of radioactive water from the Fukushima Daiichi nuclear plant into the ocean.",
    "concept_summary": "A cement-based mixture treated with hydrophobic agents (e.g., hydrophobic limestone powder, organosilicon monomers, silicone grease) that does not absorb water, allowing it to spread easily along trench bottoms and displace contaminated water, thereby sealing the trench and limiting diffusion of radionuclides.",
    "detailed_description": "The article describes TEPCO's plan to inject a special hydrophobic cement mixture into seaside trenches of reactors No. 2 and No. 3. The mixture's water-repellent properties enable it to spread and displace tainted water, keeping radioactive materials in the surrounding soil. Several patents are listed that detail methods for constructing semi-basements for radioactive waste, radiation-chemical treatment of cement bricks, plugging fluids for subterranean formations, and various hydrophobic cement formulations using organosilicon monomers, silicone greases, and solid silicates. The technology is positioned as a waterproofing and radiation-shielding solution for nuclear waste containment and underground construction.",
    "category": "Materials Science & Ceramics",
    "principles": [
        "Hydrophobicity",
        "Water-repellent coating",
        "Impermeability",
        "Radiation shielding"
    ],
    "scientific_domains": [
        "Materials Science",
        "Civil Engineering",
        "Environmental Engineering",
        "Nuclear Engineering"
    ],
    "mechanisms_of_action": [
        "Hydrophobic coating prevents water absorption by cement particles",
        "Creates a barrier that displaces contaminated water",
        "Immobilizes radionuclides within the sealed trench",
        "Provides additional radiation shielding through hydrophobic limestone powder"
    ],
    "materials": [
        "Portland cement",
        "Hydrophobic limestone powder",
        "Organosilicon monomer (vinylheptamethylcyclotetrasiloxane)",
        "Polymethylsiloxane liquid",
        "Silicone grease",
        "Solid silicate or metasilicate",
        "Clay",
        "Hydraulic cement"
    ],
    "energy_sources": [],
    "inputs": [
        "Contaminated groundwater",
        "Trench soil and rock",
        "Hydrophobic cement mixture components"
    ],
    "outputs": [
        "Sealed trench with reduced water leakage",
        "Immobilized radioactive material in surrounding soil"
    ],
    "claimed_performance": "The special mixture does not absorb water, allowing it to spread more easily along the trench bottom and displace tainted water, thereby preventing massive amounts of highly contaminated water from leaking into the ocean.",
    "experimental_evidence": "The article reports that TEPCO plans to inject the mixture and that previous attempts with freezing and standard cement were insufficient, but it provides no quantitative performance data.",
    "replication_status": null,
    "keywords": [
        "hydrophobic cement",
        "radioactive waste",
        "Fukushima",
        "water leakage",
        "impermeable barrier",
        "radiation shielding"
    ],
    "related_technologies": [
        "Waterproofing additives",
        "Radiation-shielding materials",
        "Cement-based sealing systems"
    ],
    "controversy_level": "low",
    "confidence_score": 0.9,
    "practicability_score": 0.7,
    "fringe_score": 0.2,
    "evidence_strength": 0.3,
    "risk_score": 0.2,
    "trl_estimate": 6,
    "source_urls": [
        "http://ajw.asahi.com/article/0311disaster/fukushima/AJ201411220029"
    ],
    "organizations": [
        "Tokyo Electric Power Company (TEPCO)",
        "Nuclear Regulation Authority",
        "Various patent holders (e.g., KR, US, CN, JP, GB agencies)"
    ],
    "applications": [
        "Sealing of underground trenches at nuclear sites",
        "Containment of radioactive waste",
        "Water-proofing of underground structures"
    ],
    "limitations": [
        "Effectiveness not quantified in the article",
        "Long-term durability under seismic activity unknown",
        "Requires proper mixing and application techniques"
    ],
    "open_questions": [
        "How does the hydrophobic cement perform over years of exposure to groundwater?",
        "Can the technology be scaled to larger trench networks?",
        "What is the cost compared to conventional sealing methods?"
    ],
    "red_flags": [],
    "evidence_quotes": [
        "\"The special mixture does not absorb water so it can spread more easily along the bottom of the trenches, displacing the tainted water.\"",
        "\"The new method will allow radioactive materials to remain in the surrounding soil, but TEPCO decided to employ the technique because it puts high priority on preventing massive amounts of highly contaminated water from leaking into the ocean.\"",
        "\"The company then attempted to stop the water inflow with a cement mixture, but was unable to do so completely.\"",
        "\"Hydrophobic limestone powder, a radiation shielding sheet, and a waterproof panel between the ground and a wall while constructing an upper structure...\"",
        "\"The process provides the increasing of hydrophobic and strength properties of cement brick.\""
    ]
}