Hideki Misaka

Central Research Institute of Electric Power Industry | CRIEPI · Electric Power Engineering Research Laboratory

In order to determine the effective temperature condition for artificially accelerating propagation of harmful water trees in insulation of 3.3 to 77 kV XLPE cables, an AC voltage of 13 kV and 1200 Hz was applied to a 22 kV XLPE cable removed from service at room temperature, 50°C, 60°C and 70°C, and under the heat cycle conditions between room tem...

Ethylene propylene rubber insulation under operation for 16 years in boiling water reactor containments was subjected to additional thermal aging at 110°C. After 70 days of aging, the mechanical property of the insulation was decreased such that the limit guaranteeing durability against design-basis events was breached. This degradation rate is thr...

As for polymeric cable insulations used in nuclear power plants, acceleration aging is used both for type tests and for aging estimation. In order to explain both degradation phenomena, which occur under the test conditions and under actual operation environments, numerical calculation programs are needed. The present paper refines such program to...

Flame-retardant ethylene-propylene-diene rubbers were subjected to acceleration aging with simultaneous heat and radiation in the air to evaluate the acceleration factor. Mechanical properties under various dose rates, temperatures, and degradation time (0-1050 Gy/h, 80-120°C, 0-42481 hours) were measured to find the optimal shift factor to minimiz...

Ethylene propylene rubber insulations under operation for 16 years in boiling water reactor containments were subjected to additional thermal aging at 110°C. 70 days were needed to decrease their mechanical property to the limit that they cannot secure the durability against design-basis events. This degradation rate is found to be three times slow...

Statistical analysis was performed on aging trends of ethylene-propylene rubbers used for safety cables within boiling water reactor (BWR) containments of nuclear power plants. In order to obtain a regressed aging trend curve, observed mechanical elongation at break data was converted for equivalent period in an environment of 60°C and 10 mGy/h. Dr...

Statistical analysis has been performed on variously aged ethylene propylene rubber insulation on cables removed from boiling water reactor-type containment. Temperature and dose rate conditions of such cables are not identical. Therefore, elongation at break data observed for such insulation are converted to each equivalent period under 60 °C, 10...

We have evaluated the thermal and radiation degradation of flame-retardant ethylene-propylene rubber (EPR) insulators used for safety cables in nuclear power plants. Accelerated degradation of EPR sheets was conducted under conditions of (1) simultaneous thermal-radiation aging (100 °C and 1.0 kGy/h), (2) radiation aging (room temperature and 1.0 k...

Low-temperature anionic ring-opening homopolymerizations and copolymerizations of two glycidol derivatives (allyl glycidyl ether (AGE) and ethoxyethyl glycidyl ether (EEGE)) are studied using a metal-free catalyst system, 3-phenyl-1-propanol (PPA) (an initiator) and 1-tert-butyl-4,4,4-tris(dimethylamino)-2,2-bis[tris-(dimethylamino)phosphoranyliden...

For the living ring-opening polymerization (ROP) of epoxy monomers, the catalytic activity of organic superbases, tert-butylimino-tris(dimethylamino)phosphorane, 1-tert-butyl-2,2,4,4,4-pentakis(dimethylamino)-2Λ5,4Λ5-catenadi(phosphazene), 2,8,9-triisobutyl-2,5,8,9-tetraaza-1-phosphabicyclo[3.3.3]undecane, and 1-tert-butyl-4,4,4-tris(dimethylamino)...

The ring-opening polymerization (ROP) of styrene oxide (SO) was carried out using 3-phenyl-1-propanol (PPA) as the initiator and a phosphazene base, 1-tert-butyl-4,4,4-tris(dimethylamino)-2,2-bis[tris(dimethylamino)phosphoranylidenamino]-2Λ5,4Λ5-catenadi(phosphazene) (t-Bu-P4), as the catalyst at room temperature. The polymerization proceeded in a...

The living ring-opening polymerization of l-lactide was carried out by using organocatalyst to synthesize the molecular weight controlled poly(l-lactide) with an phenylacetylenyl end group (HCCPLLA), then the homopolymerization of HCCPLLA was performed by using two different rhodium catalysts. Low molecular weight poly-PLLA6-1 (Mw,SEC-MALLS=46,700)...

The cationic ring-opening multibranching polymerization of 2-hydroxymethyloxetane (1) as a novel latent AB(2)-type monomer was carried out using trifluoromethane sulfonic acid or trifluoroboron diethyl etherate by a slow-monomer-addition (SMA) method. The polymer yield of poly-1 ranged from ca. 58-88%, which increase with the increasing monomer add...

The living ring-opening polymerization of δ-valerolactone (VL) initiated from 6-azide-1-hexanol using 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and 1-[3,5-bis(trifluoromethyl)phenyl]-3-cyclohexylthiourea (BCT) was carried out to prepare the poly(δ-valerolactone)s (N3−PVL−OH) bearing azide groups at the α-chain ends with Mn,NMRs (PDIs) of 2600 (1.08)...

The copolymerization of ethylene (E) and norbornene (NB) was investigated using the commercially available and inexpensive catalyst system, cyclopentadienylzirconium trichloride (CpZrCl3)/isobutyl-modified methylaluminoxane (MMAO), at a moderate polymerization temperature in toluene. For the CpZrCl3 catalyst system activated by aluminoxane with a 4...

Norbornene polymerization using the commercially available and inexpensive catalyst system, cyclopentadienylzirconium trichloride (CpZrCl3) and isobutyl-modified methylaluminoxane (MMAO), were carried out over a wide range of polymerization temperatures and monomer concentrations. For the CpZrCl3 catalyst system activated by aluminoxane with a 40 m...