A Captain reports a CRJ-200 door close assist motor would not disengage; preventing the Flight Attendant and himself from opening the forward passenger door after gate arrival. Door close assist motor circuit breaker in cockpit had to be pulled to de-energize motor and allow door to open for passenger egress.

Narrative

At the conclusion of an otherwise uneventful flight; we ran the shutdown checklist. When the seat belt sign was turned off; the Flight Attendant attempted to open the passenger door. She was able to open the door handle with ease; but was unable to push the door open. I went back to help her and realized the resistance felt on the door was due to the Door Close Assist mechanism being engaged without command. I then jiggled the Door Close Assist button at the Flight Attendant station in an effort to deactivate it. When that failed to work; the First Officer and myself began searching for the appropriate Circuit Breaker (CB) to de-energize the motor. We summarily located CBP 1; Grid F1; and opened the CB. Normal deplaning ensued after that. Maintenance Control was then contacted with the logbook write-up number for the discrepancy. I perceive at least two safety hazards with this situation. One being difficulty egressing the aircraft should the flight deck crew either become incapacitated; or if the aircraft is not properly de-powered. Another issue is the risk of the Door Close mechanism potentially created excessive heat from sustained operation and potentially starting a fire. I am not aware of any Weight-On-Wheels (WOW) logic that would deactivate the mechanism in flight; as it is not common systems knowledge. Recommend that:1. Develop a fail safe to prevent this from occurring. 2. Perhaps create a procedure to ensure the Door Close Assist mechanism de-energizes properly after use; maybe have the Flight Attendant make sure the door still moves freely before latching closed. 3. Enhance EICAS to include a Status message that indicates the Door Close Assist being engaged.