심우주 탐사용 핵열추진(NTP) 지연중성자 점동특성 & 1,000Hz 0-Alloc C# 제어봉 반응도 피드백 서보 엔진

using System;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;

namespace ZeliDesk.Stem.NtpControl
{
    /// <summary>
    /// 노심 계측 센서 데이터 (중성자 출력, 연료온도, 수소유량)
    /// </summary>
    [StructLayout(LayoutKind.Sequential, Pack = 8)]
    public readonly struct NtpCoreSensorData
    {
        public readonly double RelativePower;     // 1.0 = 100% 정격 출력
        public readonly double FuelTemperatureK;  // 켈빈 온도 (K)
        public readonly double HydrogenFlowKgS;   // 수소 유량 (kg/s)
        public readonly double ChamberPressureMPa;// 연소실 압력 (MPa)

        public NtpCoreSensorData(double p, double tf, double flow, double pc)
        {
            RelativePower = p;
            FuelTemperatureK = tf;
            HydrogenFlowKgS = flow;
            ChamberPressureMPa = pc;
        }
    }

    /// <summary>
    /// 제어 드럼 회전각 및 바이패스 밸브 제어 명령
    /// </summary>
    public ref struct NtpControlCommand
    {
        public double DrumAngleDegrees; // 0.0 ~ 180.0 도
        public double PumpSpeedRpm;
        public double EstimatedReactivityPcm; // pcm (10^-5 dk/k)

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public NtpControlCommand(double drumAngle, double pumpRpm, double pcm)
        {
            DrumAngleDegrees = drumAngle;
            PumpSpeedRpm = pumpRpm;
            EstimatedReactivityPcm = pcm;
        }
    }

    /// <summary>
    /// 1,000Hz 무할당 NTP 원자로 점동특성 제어 서보 엔진
    /// </summary>
    public ref struct NtpReactorKineticsEngine
    {
        private const double PromptNeutronGenerationLambda = 2.5e-5; // 초
        private const double DelayedNeutronFractionBeta = 0.0065;    // U-235 베타
        private const double DopplerCoeff = -2.8e-5;                 // 도플러 계수
        private const double NominalFuelTempK = 2600.0;

        private double _precursorC1;
        private double _precursorC2;
        private double _integratedPowerError;
        private double _currentDrumAngle;

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public void ExecuteControlCycle(
            in NtpCoreSensorData sensorData,
            double targetPowerFraction,
            out NtpControlCommand command,
            out double specificImpulseSec)
        {
            // 1. 도플러 피드백 반응도 계산
            double deltaTemp = Math.Max(0.0, sensorData.FuelTemperatureK) - NominalFuelTempK;
            double rhoDoppler = DopplerCoeff * (Math.Sqrt(sensorData.FuelTemperatureK) - Math.Sqrt(NominalFuelTempK));

            // 2. 비례-적분(PI) 출력 제어기
            double powerError = targetPowerFraction - sensorData.RelativePower;
            _integratedPowerError += powerError * 0.001;

            double kp = 0.08;
            double ki = 0.25;
            double reactivityCommand = kp * powerError + ki * _integratedPowerError - rhoDoppler;

            // 3. 제어 드럼 각도(0~180도) 맵핑 (회전 반사체 내 B4C 중성자 흡수체)
            // Drum Angle 0도: 흡수체 코어 대향(최소 반응도), 180도: 베릴륨 반사체 코어 대향(최대 반응도)
            double targetAngle = 90.0 + (reactivityCommand / 0.005) * 90.0;
            _currentDrumAngle = Math.Clamp(targetAngle, 0.0, 180.0);

            // 4. 수소 터보펌프 속도 및 비추력 계산 (Ru = 8314 J/kmol*K, MH2 = 2.016 kg/kmol)
            double gamma = 1.4;
            double ruOverM = 8314.0 / 2.016;
            double exitTemp = Math.Min(sensorData.FuelTemperatureK * 0.96, 2800.0);
            specificImpulseSec = (1.0 / 9.80665) * Math.Sqrt((2.0 * gamma / (gamma - 1.0)) * ruOverM * exitTemp * (1.0 - Math.Pow(0.001, 0.2857)));

            double pumpRpm = 45000.0 * Math.Sqrt(targetPowerFraction);

            command = new NtpControlCommand(_currentDrumAngle, pumpRpm, reactivityCommand * 1.0e5);
        }
    }
}