diff --git a/app/comp/moy_mod.py b/app/comp/moy_mod.py
index 24f941be..10da10e2 100644
--- a/app/comp/moy_mod.py
+++ b/app/comp/moy_mod.py
@@ -78,6 +78,8 @@ def check_moduleimpl_conformity(
         return True  # modules vides conformes
     if nb_ues == 0:
         return False  # situation absurde (pas d'UE)
+    if len(modules_coefficients) != nb_ues:
+        raise ValueError("check_moduleimpl_conformity: nb ue incoherent")
     module_evals_poids = evals_poids.transpose().sum(axis=1).to_numpy() != 0
     check = all(
         (modules_coefficients[moduleimpl.module.id].to_numpy() != 0)
diff --git a/app/models/evaluations.py b/app/models/evaluations.py
index ae91493f..1870607a 100644
--- a/app/models/evaluations.py
+++ b/app/models/evaluations.py
@@ -107,9 +107,15 @@ class EvaluationUEPoids(db.Model):
     """
 
     evaluation_id = db.Column(
-        db.Integer, db.ForeignKey("notes_evaluation.id"), primary_key=True
+        db.Integer,
+        db.ForeignKey("notes_evaluation.id", ondelete="CASCADE"),
+        primary_key=True,
+    )
+    ue_id = db.Column(
+        db.Integer,
+        db.ForeignKey("notes_ue.id", ondelete="CASCADE"),
+        primary_key=True,
     )
-    ue_id = db.Column(db.Integer, db.ForeignKey("notes_ue.id"), primary_key=True)
     poids = db.Column(
         db.Float,
         nullable=False,
diff --git a/app/scodoc/sco_edit_ue.py b/app/scodoc/sco_edit_ue.py
index 5a6b347b..6e05fc4a 100644
--- a/app/scodoc/sco_edit_ue.py
+++ b/app/scodoc/sco_edit_ue.py
@@ -33,7 +33,7 @@ from flask import url_for, render_template
 from flask import g, request
 from flask_login import current_user
 
-from app.models import Formation, UniteEns
+from app.models import Formation, UniteEns, ModuleImpl, Module
 import app.scodoc.notesdb as ndb
 import app.scodoc.sco_utils as scu
 from app.scodoc.sco_utils import ModuleType
@@ -106,8 +106,15 @@ def do_ue_create(args):
     if ues:
         raise ScoValueError('Acronyme d\'UE "%s" déjà utilisé !' % args["acronyme"])
     # create
-    r = _ueEditor.create(cnx, args)
+    ue_id = _ueEditor.create(cnx, args)
 
+    # Invalidate cache: vire les poids de toutes les évals de la formation
+    for modimpl in ModuleImpl.query.filter(
+        ModuleImpl.module_id == Module.id, Module.formation_id == args["formation_id"]
+    ):
+        modimpl.invalidate_evaluations_poids()
+    formation = Formation.query.get(args["formation_id"])
+    formation.invalidate_module_coefs()
     # news
     F = sco_formations.formation_list(args={"formation_id": args["formation_id"]})[0]
     sco_news.add(
@@ -116,7 +123,7 @@ def do_ue_create(args):
         text="Modification de la formation %(acronyme)s" % F,
         max_frequency=3,
     )
-    return r
+    return ue_id
 
 
 def do_ue_delete(ue_id, delete_validations=False, force=False):
diff --git a/migrations/versions/a57a6ee2e3cb_cascade_evaluation_poids.py b/migrations/versions/a57a6ee2e3cb_cascade_evaluation_poids.py
new file mode 100644
index 00000000..33532693
--- /dev/null
+++ b/migrations/versions/a57a6ee2e3cb_cascade_evaluation_poids.py
@@ -0,0 +1,72 @@
+"""cascade evaluation/poids
+
+Revision ID: a57a6ee2e3cb
+Revises: 730ac71eea23
+Create Date: 2021-12-13 23:39:37.586952
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = "a57a6ee2e3cb"
+down_revision = "730ac71eea23"
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_constraint(
+        "evaluation_ue_poids_ue_id_fkey", "evaluation_ue_poids", type_="foreignkey"
+    )
+    op.drop_constraint(
+        "evaluation_ue_poids_evaluation_id_fkey",
+        "evaluation_ue_poids",
+        type_="foreignkey",
+    )
+    op.create_foreign_key(
+        "evaluation_ue_poids_evaluation_id_fkey",
+        "evaluation_ue_poids",
+        "notes_evaluation",
+        ["evaluation_id"],
+        ["id"],
+        ondelete="CASCADE",
+    )
+    op.create_foreign_key(
+        "evaluation_ue_poids_ue_id_fkey",
+        "evaluation_ue_poids",
+        "notes_ue",
+        ["ue_id"],
+        ["id"],
+        ondelete="CASCADE",
+    )
+    # ### end Alembic commands ###
+
+
+def downgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_constraint(
+        "evaluation_ue_poids_evaluation_id_fkey",
+        "evaluation_ue_poids",
+        type_="foreignkey",
+    )
+    op.drop_constraint(
+        "evaluation_ue_poids_ue_id_fkey", "evaluation_ue_poids", type_="foreignkey"
+    )
+    op.create_foreign_key(
+        "evaluation_ue_poids_evaluation_id_fkey",
+        "evaluation_ue_poids",
+        "notes_evaluation",
+        ["evaluation_id"],
+        ["id"],
+    )
+    op.create_foreign_key(
+        "evaluation_ue_poids_ue_id_fkey",
+        "evaluation_ue_poids",
+        "notes_ue",
+        ["ue_id"],
+        ["id"],
+    )
+    # ### end Alembic commands ###