diff --git a/src/sink.cc b/src/sink.cc
index 5fde24893..710162cfb 100644
--- a/src/sink.cc
+++ b/src/sink.cc
@@ -41,6 +41,7 @@ Sink::~Sink() {}
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 void Sink::EnterNotify() {
   cyclus::Facility::EnterNotify();
+  LOG(cyclus::LEV_INFO4, "SnkFac") << " using random behavior " << random_size;
 
   if (in_commod_prefs.size() == 0) {
     for (int i = 0; i < in_commods.size(); ++i) {
@@ -164,9 +165,36 @@ void Sink::Tick() {
   using std::vector;
   LOG(cyclus::LEV_INFO3, "SnkFac") << prototype() << " is ticking {";
 
-  double requestAmt = RequestAmt();
+  double amt = RequestAmt();
+  double requestAmt = 0;
+
+  LOG(cyclus::LEV_INFO3, "SnkFac") << prototype() << " has default request amount " << amt;
+
   // inform the simulation about what the sink facility will be requesting
-  if (requestAmt > cyclus::eps()) {
+  if (amt > cyclus::eps()) {
+    if (random_size == "None") {
+      requestAmt = amt;
+    }
+    else if (random_size == "UniformInt") {
+      requestAmt = context()->random_uniform_int(0, amt);
+    }
+    else if (random_size == "UniformReal") {
+      requestAmt = context()->random_uniform_real(0, amt);
+    }
+    else if (random_size == "NormalReal") {
+      requestAmt = context()->random_normal_real(amt * random_size_mean,
+      amt * random_size_stddev, 0, amt);
+    }
+    else if (random_size == "NormalInt") {
+      requestAmt = context()->random_normal_int(amt * random_size_mean,
+      amt * random_size_stddev, 0, amt);
+    }
+    else {
+      requestAmt = amt;
+    }
+    LOG(cyclus::LEV_INFO4, "SnkFac") << prototype()
+                                       << " has request amount " << requestAmt
+                                       << " kg of " << in_commods[0] << ".";
     for (vector<string>::iterator commod = in_commods.begin();
          commod != in_commods.end();
          commod++) {
diff --git a/src/sink.h b/src/sink.h
index f5fabedd5..852497e43 100644
--- a/src/sink.h
+++ b/src/sink.h
@@ -154,6 +154,44 @@ class Sink
   #pragma cyclus var {'capacity': 'max_inv_size'}
   cyclus::toolkit::ResBuf<cyclus::Resource> inventory;
 
+  /// random status (size of request)
+  #pragma cyclus var {"default": "None", \
+                      "tooltip": "type of random behavior when setting the " \
+                      "size of the request", \
+                      "uitype": "combobox", \
+                      "uilabel": "Random Size", \
+                      "categorical": ["None", "UniformReal", "UniformInt", "NormalReal", "NormalInt"], \
+                      "doc": "type of random behavior to use. Default None, " \
+                      "other options are 'UniformReal', 'UniformInt', " \
+                      "'NormalReal', and 'NormalInt'"}
+  std::string random_size;
+
+  // random size mean (as a fraction of available space)
+  #pragma cyclus var {"default": 1.0, \
+                      "tooltip": "fraction of available space to determine the mean", \
+                      "uilabel": "Random Size Mean", \
+                      "uitype": "range", \
+                      "range": [0.0, 1.0], \
+                      "doc": "When a normal distribution is used to determine the " \
+                             "size of the request, this is the fraction of available " \
+                             "space to use as the mean. Default 1.0, must be between " \
+                             "0.0 and 1.0"}
+  double random_size_mean;
+
+  // random size std dev (as a fraction of available space)
+  #pragma cyclus var {"default": 0.1, \
+                      "tooltip": "fraction of available space to determine the std dev", \
+                      "uilabel": "Random Size Std Dev", \
+                      "uitype": "range", \
+                      "range": [0.0, 1e299], \
+                      "doc": "When a normal distribution is used to determine the " \
+                             "size of the request, this is the fraction of available " \
+                             "space to use as the standard deviation. Default 0.1"}
+  double random_size_stddev;
+
+
+  // random status (frequencing/timing of request)
+
   #pragma cyclus var { \
     "default": 0.0, \
     "uilabel": "Geographical latitude in degrees as a double", \