It looks like four more thermocouples inside the Reactor 2 Containment Vessel are failing:
return air drywell cooler(TE-16-114A)
return air drywell cooler(TE-16-114D)
supply air D/W cooler(TE-16-114F#1)
supply air D/W cooler(TE-16-114H#1)
The locations of these thermocouples can be (sort of) figured out with this TEPCO document, as of April 25, 2012 (I put the red rectangles around the failing thermocouples):
TEPCO's handout for press, 5/29/2012 lists "Thermometers which indicated large fluctuation". Temperatures have been fluctuating in a meaningful way (increase or decrease in large steps) since May 28 (red rectangles added to indicate the large fluctuations; click on the table for a better image):
But do not worry. TEPCO has a plan to send human workers inside the Reactor 2 building again to somehow install new thermocouples. According to the reference document for the Working Group meeting on May 28, 2012 (pages 10 to 17), the installation work should start sometime in August, after the decontamination of the 1st floor of the Reactor 2 building is complete by mid July. The trial decontamination has already been done by the workers to compare different methods (strippable paint is most effective, so is the radiation shield), and they have just stated the actual decontamination in the environment where the highest radiation level is 4,400 millisieverts/hour (on the surface of the penetration X-34, near the location that TEPCO wants to insert a new thermocouple).
I don't know why there is no robot by now that can do such a work.
Unlike Reactor 4, where carbon-based human workers routinely enter and work in the radiation levels measured in microsievert/hour, Reactors 1, 2 and 3 have much higher radiation levels measured in millisievert or even sievert/hour. Upper floors of Reactors 1, 2 and 3 are too radioactive for human workers, and even the robot (Quince) was left stranded in Reactor 2's 3rd floor because of high radiation that precluded the rescue mission.