diff --git a/build.gradle b/build.gradle
index af43a2c53c1..a14e7f68d31 100644
--- a/build.gradle
+++ b/build.gradle
@@ -48,7 +48,7 @@ ext {
 	kotlinVersion        = "1.2.51"
 	log4jVersion         = "2.11.1"
 	nettyVersion         = "4.1.29.Final"
-	reactorVersion       = "Bismuth-SR11"
+	reactorVersion       = "Bismuth-BUILD-SNAPSHOT"
 	rxjavaVersion        = "1.3.8"
 	rxjavaAdapterVersion = "1.2.1"
 	rxjava2Version       = "2.1.17"
@@ -152,6 +152,7 @@ configure(allprojects) { project ->
 
 	repositories {
 		maven { url "https://repo.spring.io/libs-release" }
+		maven { url "https://repo.spring.io/snapshot" }	// Reactor Bismuth snapshots (towards SR13)
 	}
 
 	dependencies {
diff --git a/spring-webflux/src/main/java/org/springframework/web/reactive/socket/adapter/ReactorNettyWebSocketSession.java b/spring-webflux/src/main/java/org/springframework/web/reactive/socket/adapter/ReactorNettyWebSocketSession.java
index dcf00451c74..81610f19f34 100644
--- a/spring-webflux/src/main/java/org/springframework/web/reactive/socket/adapter/ReactorNettyWebSocketSession.java
+++ b/spring-webflux/src/main/java/org/springframework/web/reactive/socket/adapter/ReactorNettyWebSocketSession.java
@@ -70,8 +70,7 @@ public class ReactorNettyWebSocketSession
 
 	@Override
 	public Mono<Void> close(CloseStatus status) {
-		WebSocketFrame closeFrame = new CloseWebSocketFrame(status.getCode(), status.getReason());
-		return getDelegate().getOutbound().sendObject(closeFrame).then();
+		return getDelegate().getOutbound().sendClose(status.getCode(), status.getReason());
 	}
 
 
diff --git a/spring-webflux/src/test/java/org/springframework/web/reactive/socket/WebSocketIntegrationTests.java b/spring-webflux/src/test/java/org/springframework/web/reactive/socket/WebSocketIntegrationTests.java
index b952d46cac3..b7c957e6b84 100644
--- a/spring-webflux/src/test/java/org/springframework/web/reactive/socket/WebSocketIntegrationTests.java
+++ b/spring-webflux/src/test/java/org/springframework/web/reactive/socket/WebSocketIntegrationTests.java
@@ -197,7 +197,10 @@ public class WebSocketIntegrationTests extends AbstractWebSocketIntegrationTests
 
 		@Override
 		public Mono<Void> handle(WebSocketSession session) {
-			return Flux.never().mergeWith(session.close(CloseStatus.GOING_AWAY)).then();
+			return session.send(Flux
+					.error(new Throwable())
+					.onErrorResume(ex -> session.close(CloseStatus.GOING_AWAY)) // SPR-17306 (nested close)
+					.cast(WebSocketMessage.class));
 		}
 	}