IR 05000324/2018011

NRC Design Bases Assurance Inspection (Programs) Report No. 05000325/2018011 and 05000324/2018011

ML18176A352
Person / Time
Site:	Brunswick
Issue date:	06/22/2018
From:	Sykes M D NRC/RGN-II/DRS/EB1
To:	Gideon W R Duke Energy Progress
References
IR 2018011
Download: ML18176A352 (16)

Text

/RA/

Qualification by analysis shall require the construction of a valid mathematical model of the electric equipment to be qualified, in which the performance characteristics of the equipment are the dependent variables and the environmental influences are the independent variable The validity of the mathematical model shall be justified by test data, operating experience, or physical laws of natur Qualification shall consist of a quantitative analysis of the mathematical model of the electric equipment that shall logically prove that the performance characteristics of the equipment meet or exceed the equipment design specifications when the equipment is subjected to the design basis event environmen Qualified life shall be determined from the time dependent effects of the environmental influences by quantitatively demonstrating that the performance characteristics of the equipment meet or exceed the design specifications of the equipment after a design basis event, preceded by a time period during which the equipment is subjected to its normal design environment."

thermal qualified life values may vary depending on the method used for determination as well as the data used in thermal life calculation ...ASCO programs used Arrhenius calculations but were based on ambient temperatures rather than actual component temperature Since there are many variables that must be considered in qualified life calculations and since the NRC has not endorsed any single thermal qualified life calculation method, ASCO leaves it to each individual user to determine the appropriate qualified life calculation method for each specific application.airflow internal to the solenoid valve body is considered to be static/stagnant, and the body and housing cover of the solenoid valve are exposed to the maintained temperature value of the ove During the oven tests to develop the FV-series drawings and data , the sample materials were subjected to natural recirculation effects within the oven.based on the information summarized herein, ASCO has conservatively chosen to apply the following activation energy values in all Arrhenius calculation used in connection with ASCO Catalog NP-1 valves:

• All Ethylene Propylene Terpolymer (EPDM) Elastomers, 0.94 eV

• Viton Elastomers (except Bulletin NP8316 Viton Diaphragms), 1.04 eV

• Viton Diaphragms in Bulletin NP8316 Valves, 0.96 eV

• All Solenoid Coils, 1.00 eV. the data base is incomplete, as the UL report lists 13 different wires that could be on coils already delivere Supplement 3 asserts a minimum of 1.16 eV , but the reference to 1.16 eV is a Dow Corning report about silicon Since the insulation is not silicone, this is erroneous data and must be delete The next highest eV is 1.32 based on DuPont data, and that is now justified as the lowest verifiable.for the new ASCO valves currently in test, the activation energy will be 1.15 eV.the UL report lists 13 different wires that could be on coils already delivere Principles and procedures for demonstrating the qualification of Class 1E equipment include: (1) Assurance that the severity of the qualification methods equal or exceed the maximum anticipated service requirements and conditions, (2) Assurance that any extrapolation or inference be justified by allowances for known potential failure modes and the mechanism leading to them."although the heater is not a seismically or environmentally qualified part and is intended for use only during storage, its use has been shown to cause serious degradation of environmentally qualified internal wiring [and that] - three of the four operators were found to contain burnt internal wirin One type SMB-00 operator also was inspected and was found to contain wiring susceptible to damag the heaters provided by Limitorque are principally of a wire-wound/ceramic construction, although some are of a carbon-film/ceramic constructio The heaters are stud mounted with wiring bolted to two contact ears located at the opposite ends of the resisto Limitorque noted that the heaters are typically sized to provide a 10 ºC temperature rise in the LSC . However, the actual temperature rise will vary based on the LSC configuration, orientation, and installed component In November 1978, a Limitorque test was conducted by applying proper voltage to a Ward Leonard space heater allowing the surface temperature to stabilize (measured at 250 degrees F),Limitorque recognizes some utility interest in utilizing energized heaters to minimize the effects of moisture related degradation and corrosio However, no additional Limitorque test information supporting the qualification and use of heaters is available. The use of heaters should address 1) the heat rise and associated impact on qualified life of LSC components, 2) subfusing of unqualified heaters to prevent propagation of electrical failures to safety related LSC components and other circuits, and 3) failure modes and effects analysis of unqualified heaters to demonstrate that hypothesized environmental failures will not affect actuator performanc **