Reading through the redacted BOC reports, I didn't see any indicators that there was an intent on replacing the anchor tendons (in this phase of the contract).
There is not much choice in options regarding the density of these tendons. They are strategically placed to distribute the focus of the arc of stress from the trunnion gates. You don't want to "swiss cheese" the contributing structural concrete with alternate drillings. Replacement requires a process to evacuate the tendon & the grout while likely side coring out the anchor "Tee".
However, I believe that DWR is still banking on FDH Velocitel's Dispersal Wave testing results to make any decisions on tendon replacements (DWR states FDH Velocitel's results not expected until Sep 1, 2017). This proprietary technique is still in the "proving out" stage. There could be uncertainties in the conclusions. Below is the efforts taken to be "certain" on 1960's era tendons that include hydraulic "lift-off" testing. Lift-off testing will prove out how much tension is remaining in the tendon (actual psi). Because so many dams have had 50 year old steel tendons fail, there should be an effort to replace all of Oroville's anchor tendons while the "cash is flowing" (copyright KC Burke). I suspect the logistics of getting all of these tendons replaced in a tight schedule is a limiting factor. You must have time to deal with variances to the repair process (i.e. surprises). Logistics require a "parallel" process of replacement. A "serial" process multiplies the repair time. Where are they going to get a large number of skilled outfits that can work on all 384 in "bunches" as fast as possible?
Oroville Dam Anchor Tendons - identical type, age, & corrosion failures as noted in this mini-report - how to determine "certainty" in the state of anchor tendons - includes hydraulic "lift-off" test
