Small Transport; Low Wing; 2 Turbojet Eng
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 11
Situational Awareness; Distraction
Airspace Violation All Types; Conflict Airborne Conflict; Deviation / Discrepancy - Procedural Published Material / Policy
Air Traffic Control Separated Traffic
Airspace Structure
I was training a new person on the sector.  Aircraft X was given vectors for visual approach at 4;000 FT.  The aircraft was then given a base turn to final and descent to 3;400 FT.  The SFO class Bravo airspace does not protect for the OAK or HWD finals.  VFR aircraft northeast bound got in the way of the Aircraft X.  Pilot responded to the TCAS.  Traffic was issued and alternate course of action was given.  Pilot descended into lower MVA.Redesign SFO Bravo to help with IFR traffic into OAK and HWD airports.
Aircraft X; landing at HWD Tower; entered the downwind and was handed off from Richmond Sector.  At the time of handoff; HWD Tower called for a release of Aircraft Y with a flight plan that intended for him to transition northbound.  I; the Mulford/Grove controller; issued to the release to HWD.  I then extended Aircraft X to allow for ample room to depart and turn the Aircraft Y northbound without incident.  Once Aircraft Y departed; I turned Aircraft X to a base leg to keep him inside of an OAK Aircraft Z arrival that he must also be separated from.  I noticed an uncorrelated VFR target southeast of Aircraft X; but thought he would turn inside the prescribed traffic.  As Aircraft X rolled out of his turn his path projected increasing close to the other aircraft.  As I issued traffic; Aircraft X stated that he was responding to a TCAS/RA and that he was descending.  During this time; Aircraft X descended below the MVA.  I asked Aircraft X if he had the ground and runway insight.  He stated affirmative and I then cleared him for the visual approach.  Aircraft X landed without incident.My actions could have been better in alleviating part of this problem.  I knew the VFR aircraft was out there; but assumed Aircraft X would turn inside the aircraft.  I should have turned Aircraft X sooner and kept him at 4;000 MSL to give Aircraft X a better chance at avoidance.  I did not want to slow Aircraft X because I wanted him to stay in front of following traffic. Another recommendation I would make is allow the class Bravo to protect OAK & HWD traffic.  Too many commercial and business aircraft are violated by aircraft transitioning the final approach course at intercept altitude.  It is a daily occurrence that Mulford/Grove controllers are having to cancel approaches and dodge aircraft that are coming within 200 FT of their aircraft.  Even if the Class Bravo were allowed to protect OAK traffic; that may have alleviated this problem from occurring.
Two NCT controllers report of issues with the SFO Class Bravo not protecting OAK and HWD traffic causing approach clearances to be canceled due to traffic conflicts.