diff --git a/templates/ti-cl4/llm-scenarios/config/alarm_explain.template.yaml b/templates/ti-cl4/llm-scenarios/config/alarm_explain.template.yaml
new file mode 100644
index 0000000..970efae
--- /dev/null
+++ b/templates/ti-cl4/llm-scenarios/config/alarm_explain.template.yaml
@@ -0,0 +1,22 @@
+# -*- coding: utf-8 -*-
+# 模板「报警解释」场景配置资产：ti-cl4（Template-Ti 一期，issue #74）。
+#
+# 说明（父 Issue #11「④ LLM 报警解释 / 交接班 / NL 查询」子任务）：
+# - prompt_template：绑定 llm-gateway 提示词版本库（prompts.template.yaml）
+#   中的 alarm_explain 模板（报警解释 + SOP 引用）；
+# - rag.categories：报警解释**只检索 sop 知识域**（异常处置 SOP），
+#   不引入工艺规范/国标噪声，保证引用精准；
+# - rag.min_score：检索阈值（TF 密度分），低于阈值视为未命中 →
+#   提示"未检索到相关 SOP，请人工确认"（高利害场景宁缺毋滥，PRD 5.4）；
+# - high_stakes + confidence_threshold：低信度转人工确认（与 #11 验收一致）。
+template: ti-cl4
+version: 1.0.0
+
+alarm_explain:
+  prompt_template: alarm_explain
+  rag:
+    categories: [sop]      # 报警解释知识域：仅异常处置 SOP
+    top_k: 3
+    min_score: 0.3         # 检索阈值（低于 = 未命中，降级提示人工）
+  high_stakes: true
+  confidence_threshold: 0.8   # 低信度转人工
diff --git a/templates/ti-cl4/llm-scenarios/scenarios.py b/templates/ti-cl4/llm-scenarios/scenarios.py
index 48af168..9b960cd 100644
--- a/templates/ti-cl4/llm-scenarios/scenarios.py
+++ b/templates/ti-cl4/llm-scenarios/scenarios.py
@@ -19,7 +19,7 @@ from typing import Callable, Dict, List, Optional
 from llm_gateway.gateway import GatewayResult, LLMGateway
 from llm_gateway.prompts import PromptRegistry
 from llm_gateway.router import SensitivityRouter
-from rag_kb import RagKnowledgeBase, load_kb_config
+from rag_kb import KnowledgeSourceKind, RagKnowledgeBase, load_kb_config
 
 # ---------------------------------------------------------------------------
 # 场景配置资产路径
@@ -41,6 +41,12 @@ def scenarios_config_path() -> str:
     return os.path.join(_scenarios_dir(), "config", "scenarios.template.yaml")
 
 
+def alarm_config_path() -> str:
+    """报警解释场景配置资产（alarm_explain.template.yaml）路径。"""
+    return os.path.join(_scenarios_dir(), "config",
+                        "alarm_explain.template.yaml")
+
+
 def prompts_config_path() -> str:
     """复用 llm-gateway 提示词版本库资产路径。"""
     return os.path.join(_repo_root(), "core", "llm-gateway", "config",
@@ -110,6 +116,7 @@ class TiScenarioRunner:
         prompts: Optional[PromptRegistry] = None,
         router: Optional[SensitivityRouter] = None,
         kb_loader: Callable[[str], str] = demo_kb_loader,
+        alarm_config: Optional[dict] = None,
     ) -> None:
         prompts = prompts or PromptRegistry.from_template_config(prompts_config_path())
         kb = kb or RagKnowledgeBase.from_template_config(
@@ -117,6 +124,8 @@ class TiScenarioRunner:
         )
         router = router or SensitivityRouter.from_template_config(router_config_path())
         self.kb = kb
+        # 报警解释场景配置（issue #74：sop 类目检索 + 检索阈值）
+        self.alarm_cfg = alarm_config or self._load_alarm_config()
         if gateway is not None:
             # 注入 gateway：由调用方负责 prompt_name / 高利害配置
             self._gateways = {
@@ -141,12 +150,35 @@ class TiScenarioRunner:
 
     # -- 场景 1：报警根因解释（高利害） -----------------------------------
 
+    @staticmethod
+    def _load_alarm_config() -> dict:
+        """加载报警解释场景配置资产（issue #74）。"""
+        import yaml
+
+        with open(alarm_config_path(), "r", encoding="utf-8") as fh:
+            return (yaml.safe_load(fh) or {}).get("alarm_explain", {})
+
     def explain_alarm(self, alarm: str, confidence: float = 1.0,
-                      top_k: int = 3) -> GatewayResult:
-        """解释一条报警的可能原因与处置建议（RAG 检索异常处置 SOP）。"""
-        hits = self.kb.search(alarm, top_k=top_k,
-                              categories=None)
-        sources = [h.source for h in hits]
+                      top_k: Optional[int] = None) -> GatewayResult:
+        """解释一条报警的可能原因与处置建议。
+
+        RAG 接入（issue #74）：只检索 **sop 知识域**（异常处置 SOP），
+        并按 min_score 过滤——低于阈值视为未命中，降级提示人工确认
+        （高利害场景宁缺毋滥，避免无据回答）。
+        """
+        rag = self.alarm_cfg.get("rag", {}) or {}
+        cat_names = rag.get("categories")
+        categories = ([KnowledgeSourceKind(c) for c in cat_names]
+                      if cat_names else None)
+        top_k = top_k or int(rag.get("top_k", 3))
+        min_score = float(rag.get("min_score", 0.0))
+        hits = self.kb.search(alarm, top_k=top_k, categories=categories)
+        hits = [h for h in hits if h.score >= min_score]
+        if hits:
+            sources = [h.source for h in hits]
+        else:
+            # 未检索到 SOP：降级提示人工确认（来源占位，阻断无据回答）
+            sources = ["未检索到相关 SOP，请人工确认"]
         return self._gateways["alarm_explain"].ask(
             alarm, rag_context=sources, confidence=confidence,
         )
diff --git a/templates/ti-cl4/llm-scenarios/tests/test_scenarios.py b/templates/ti-cl4/llm-scenarios/tests/test_scenarios.py
index f794389..b82ec07 100644
--- a/templates/ti-cl4/llm-scenarios/tests/test_scenarios.py
+++ b/templates/ti-cl4/llm-scenarios/tests/test_scenarios.py
@@ -105,6 +105,21 @@ class TestScenariosE2E(unittest.TestCase):
         self.assertIn("来源", result.answer)
         self.assertEqual(result.route.target, RouteTarget.LOCAL)
 
+    def test_explain_alarm_rag_sop_only(self):
+        """报警解释 RAG 接入（issue #74）：只检索 sop 知识域并回显来源。"""
+        result = self.runner.explain_alarm("炉温超上限报警怎么处理")
+        # 演示库 sop 类目（异常处置SOP）应被检索到并随答案溯源
+        self.assertIn("SOP", result.answer)
+
+    def test_explain_alarm_min_score_fallback(self):
+        """检索阈值（issue #74）：低分视为未命中 → 降级提示人工确认。"""
+        # 注入高 min_score 配置：正常演示库检索得分低于阈值 → 降级
+        runner = TiScenarioRunner(alarm_config={
+            "rag": {"categories": ["sop"], "top_k": 3, "min_score": 99.0},
+        })
+        result = runner.explain_alarm("炉温超上限报警怎么处理")
+        self.assertIn("人工确认", result.answer)
+
     def test_shift_handover(self):
         result = self.runner.generate_handover("甲班：生产平稳，炉温正常，无异常事项")
         self.assertTrue(result.answer)