diff --git a/src/main.cpp b/src/main.cpp
index e1415bb..ca2ed0a 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -20,21 +20,28 @@ int main()
 	
 	sim::reactor::reactor<5, 5> reactor = sim::reactor::builder<5, 5>(
 		sim::reactor::fuel::fuel_rod(100, 400),
-		sim::reactor::control::control_rod(1000),
+		sim::reactor::control::control_rod(1000, 0.1),
 		sim::reactor::coolant::pipe(), {
-			"  P  ",
-			" FCF ",
+			" PPP ",
+			"PFCFP",
 			"PCPCP",
-			" FCF ",
-			"  P  "
+			"PFCFP",
+			" PPP "
 		});
 
+	double secs = 0;
+
 	for(;;)
 	{
-		reactor.update(1);
+		reactor.update(0.01);
+
+		std::stringstream ss;
+		ss << "Reactor Core: " << secs << " s\n";
+
+		secs += 0.01;
 
 		erase();
-		display::draw_text(1, 0, "Reactor Core:");
+		display::draw_text(1, 0, ss.str().c_str());
 
 		const int X = 3, Y = 4;
 		const int W = 32, H = 8;
@@ -76,10 +83,10 @@ int main()
 			reactor.move_cursor(1);
 			break;
 		case KEY_UP:
-			reactor.update_selected(0.001);
+			reactor.update_selected(0.01);
 			break;
 		case KEY_DOWN:
-			reactor.update_selected(-0.001);
+			reactor.update_selected(-0.01);
 			break;
 		case ' ':
 			reactor.toggle_selected();
diff --git a/src/reactor/control/control_rod.cpp b/src/reactor/control/control_rod.cpp
index c735756..847240e 100644
--- a/src/reactor/control/control_rod.cpp
+++ b/src/reactor/control/control_rod.cpp
@@ -1,11 +1,14 @@
 
 #include "control_rod.hpp"
 
+#include <cmath>
+
 using namespace sim::reactor::control;
 
-control_rod::control_rod(double limit)
+control_rod::control_rod(double limit, double max)
 {
 	this->limit = limit;
+	this->max = max;
 }
 
 void control_rod::display(std::ostream& o) const
@@ -38,7 +41,7 @@ void control_rod::update(double secs)
 {
 	update_rod();
 	
-	double m = (1 - absorbed / limit) * inserted;
+	double m = 1 - std::pow(0.5, (1 - absorbed / limit) * inserted * max);
 	double r_fast = vals[val_t::N_FAST] * m;
 	double r_slow = vals[val_t::N_SLOW] * m;
 
diff --git a/src/reactor/control/control_rod.hpp b/src/reactor/control/control_rod.hpp
index 9a7c39d..9d19ef6 100644
--- a/src/reactor/control/control_rod.hpp
+++ b/src/reactor/control/control_rod.hpp
@@ -11,6 +11,7 @@ class control_rod : public sim::reactor::rod
 	double inserted = 1;
 	double absorbed = 0;
 	double limit;
+	double max;
 	
 	virtual double get_k(sim::reactor::rod::val_t type) const;
 	virtual void display(std::ostream& o) const;
@@ -20,7 +21,7 @@ class control_rod : public sim::reactor::rod
 
 public:
 
-	control_rod(double limit);
+	control_rod(double limit, double max);
 
 	virtual void update(double secs);
 	void set_reactivity(double a);
diff --git a/src/reactor/coolant/pipe.hpp b/src/reactor/coolant/pipe.hpp
index 13405a5..b6a8ae5 100644
--- a/src/reactor/coolant/pipe.hpp
+++ b/src/reactor/coolant/pipe.hpp
@@ -10,7 +10,7 @@ class pipe : public sim::reactor::rod
 {
 	virtual double get_k(sim::reactor::rod::val_t type) const;
 	
-	virtual const char* get_name() const { return "Coolant Pipe"; }
+	virtual const char* get_name() const { return "Coolant"; }
 	virtual bool should_display() const { return true; }
 
 public:
diff --git a/src/reactor/fuel/fuel_rod.cpp b/src/reactor/fuel/fuel_rod.cpp
index b476fc8..3dd2bb3 100644
--- a/src/reactor/fuel/fuel_rod.cpp
+++ b/src/reactor/fuel/fuel_rod.cpp
@@ -11,6 +11,7 @@ fuel_rod::fuel_rod(double fuel, double mass) : s(fuel, mass)
 void fuel_rod::display(std::ostream& o) const
 {
 	o << "Fuel: " << s.get_fuel() << " / " << s.get_mass() << "\n";
+	o << "Efficiency: " << s.get_efficiency() << "\n";
 	o << "Energy: " << s.get_energy() << "\n";
 }
 
diff --git a/src/reactor/fuel/sample.cpp b/src/reactor/fuel/sample.cpp
index b1aa35b..e6058bc 100644
--- a/src/reactor/fuel/sample.cpp
+++ b/src/reactor/fuel/sample.cpp
@@ -4,7 +4,6 @@
 
 using namespace sim::reactor::fuel;
 
-static const double Xe_135_M = 1e4;
 static const double NEUTRON_BG = 1e-10;
 
 sample::sample(double fuel, double mass)
@@ -45,14 +44,28 @@ void sample::update(double secs)
 	slow_neutrons = 0;
 
 	// deal with these edge cases
-	if(neutrons_fuel > fuel) neutrons_fuel = fuel;
-	if(neutrons_xenon > xe_135) neutrons_xenon = xe_135;
-	if(neutrons_iodine > i_135) neutrons_iodine = i_135;
+	
+	if(neutrons_fuel > fuel)
+	{
+		slow_neutrons += neutrons_fuel - fuel;
+		neutrons_fuel = fuel;
+	}
+
+	if(neutrons_xenon > xe_135)
+	{
+		slow_neutrons += neutrons_xenon - xe_135;
+		neutrons_xenon = xe_135;
+	}
+	
+	if(neutrons_iodine > i_135)
+	{
+		slow_neutrons += neutrons_iodine - i_135;
+		neutrons_iodine = i_135;
+	}
 
 	// sim::reactor::fuelulate fuel use
 	fuel -= neutrons_fuel;
 	energy += neutrons_fuel;
-	fast_neutrons += neutrons_fuel * 3;
 	waste.add_fissile(neutrons_fuel * 2);
 
 	// do the poison
@@ -61,11 +74,6 @@ void sample::update(double secs)
 	i_135 -= neutrons_iodine;
 }
 
-double sample::get_volume() const
-{
-	return mass + xe_135 * Xe_135_M;
-}
-
 double sample::extract_energy()
 {
 	double v = energy;
diff --git a/src/reactor/fuel/sample.hpp b/src/reactor/fuel/sample.hpp
index 7b20a2c..4278319 100644
--- a/src/reactor/fuel/sample.hpp
+++ b/src/reactor/fuel/sample.hpp
@@ -10,6 +10,8 @@ namespace sim::reactor::fuel
 
 class sample
 {
+	constexpr static const double Xe_135_M = 1e3;
+
 	sim::reactor::fuel::waste waste;
 	
 	double fuel = 0;
@@ -36,8 +38,8 @@ public:
 	constexpr double get_fuel() const { return fuel; }
 	constexpr double get_mass() const { return mass; }
 	constexpr double get_energy() const { return energy; }
-
-	double get_volume() const;
+	constexpr double get_volume() const { return mass + xe_135 * Xe_135_M; }
+	constexpr double get_efficiency() const { return fuel / get_volume(); }
 
 	friend std::ostream& operator<<(std::ostream& o, const sample& s)
 	{
diff --git a/src/reactor/fuel/waste.cpp b/src/reactor/fuel/waste.cpp
index 45178f5..7225895 100644
--- a/src/reactor/fuel/waste.cpp
+++ b/src/reactor/fuel/waste.cpp
@@ -4,10 +4,13 @@
 
 using namespace sim::reactor::fuel;
 
+static const double SLOWDOWN_M = 1.0 / 4.0;
+
 void waste::update(double secs)
 {
 	double hl = 1;
-	double next[waste::N - 1] = {0};
+	double next_h[waste::N - 1] = {0};
+	double next_l[waste::N - 1] = {0};
 
 	for(int i = 0; i < waste::N - 1; i++)
 	{
@@ -15,7 +18,8 @@ void waste::update(double secs)
 		double h = high[i] * m;
 		double l = low[i] * m;
 
-		next[i] += h + l;
+		next_h[i] += h * (1 - SLOWDOWN_M);
+		next_l[i] += l + h * SLOWDOWN_M;
 		high[i] -= h;
 		low[i] -= l;
 
@@ -26,7 +30,8 @@ void waste::update(double secs)
 
 	for(int i = 0; i < waste::N - 1; i++)
 	{
-		low[i + 1] += next[i];
+		high[i + 1] += next_h[i];
+		low[i + 1] += next_l[i];
 	}
 }
 
diff --git a/src/reactor/rod.hpp b/src/reactor/rod.hpp
index 2590d3d..a8aad26 100644
--- a/src/reactor/rod.hpp
+++ b/src/reactor/rod.hpp
@@ -37,7 +37,7 @@ public:
 
 		o << r.get_name() << "\n";
 		r.display(o);
-		o << "Heat: " << r.get(val_t::HEAT) << "\n";
+//		o << "Heat: " << r.get(val_t::HEAT) << "\n";
 		o << "Fast: " << r.get(val_t::N_FAST) << "\n";
 		o << "Slow: " << r.get(val_t::N_SLOW) << "\n";