diff --git a/core/src/io/anuke/mindustry/entities/traits/BuilderTrait.java b/core/src/io/anuke/mindustry/entities/traits/BuilderTrait.java
index a4c59b4d53..bb02ed792d 100644
--- a/core/src/io/anuke/mindustry/entities/traits/BuilderTrait.java
+++ b/core/src/io/anuke/mindustry/entities/traits/BuilderTrait.java
@@ -113,7 +113,7 @@ public interface BuilderTrait extends Entity, TeamTrait{
     /** @return whether this request should be skipped, in favor of the next one. */
     default boolean shouldSkip(BuildRequest request, @Nullable TileEntity core){
         //requests that you have at least *started* are considered
-        if(state.rules.infiniteResources || request.breaking || !request.initialized) return false;
+        if(state.rules.infiniteResources || request.breaking || !request.initialized || core == null) return false;
         return request.stuck && !core.items.has(request.block.requirements);
     }
 
diff --git a/core/src/io/anuke/mindustry/world/blocks/power/NuclearReactor.java b/core/src/io/anuke/mindustry/world/blocks/power/NuclearReactor.java
index 3eead0b96c..50d489fcb2 100644
--- a/core/src/io/anuke/mindustry/world/blocks/power/NuclearReactor.java
+++ b/core/src/io/anuke/mindustry/world/blocks/power/NuclearReactor.java
@@ -33,7 +33,7 @@ public class NuclearReactor extends PowerGenerator{
     protected Color coolColor = new Color(1, 1, 1, 0f);
     protected Color hotColor = Color.valueOf("ff9575a3");
     protected float itemDuration = 120; //time to consume 1 fuel
-    protected float heating = 0.01f; //heating per frame * fullness
+    protected float heating = 0.005f; //heating per frame * fullness
     protected float smokeThreshold = 0.3f; //threshold at which block starts smoking
     protected int explosionRadius = 40;
     protected int explosionDamage = 1350;