Junk CDRMs: Massive Employee Radiation Dose and Might Have to Replace Heads?

How is this associated to the damaged baffle plate screws and with lower upper head bypass flow? 
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The two plants with high levels of BFB degradation are Westinghouse reactors with a 4-loop design, operating in a downflow configuration with Type 347 stainless steel bolts.  The NRC staff determined that plants with these characteristics are most susceptible to high levels of BFB degradation and identified a total of seven reactors in this group.  Although the two plants that found extensive bolt degradation have taken corrective actions, including...

Table 1: Plants with Higher Susceptibility to Thermal Sleeve Flange Wear A.W. Vogtle 1 & 2 Maanshan 1 & 2 Ascó I & II McGuire 1 & 2 Braidwood 1 & 2 Millstone 3 Byron 1 & 2 Seabrook Callaway Sequoyah 1 & 2 Catawba 1 & 2 Shearon Harris Comanche Peak 1 & 2 Sizewell B Diablo Canyon 2 South Texas 1 & 2 Doel 4* Tihange 3* Hanbit 1 & 2 Watts Bar 1 & 2 Kori 2*, 3 & 4 Wolf Creek
* T-hot but T-cold capable
2 T-Cold capable plants are essentially a hybrid of T-Hot and T-Cold with some head spray cooling nozzles plugged and some open (not quite T-Cold).  In this configuration there is uncertainty as to whether the local jets will cause local flow conditions similar to T-Cold; therefore, these plants are conservatively assumed to have a higher susceptibility to thermal sleeve flange wear. 
NSAL-18-1 Page 7 of 10
Table 2: Plants with Lower Susceptibility to Thermal Sleeve Flange Wear Almaraz 1 & 2 Point Beach 1* & 2* Angra 1 Prairie Island 1* & 2* Beaver Valley 1 & 2 R.E. Ginna* D.C. Cook 1 & 2 Ringhals 2, 3 & 4 Diablo Canyon 1 Salem 1 & 2 Doel 1** & 2** Surry 1 & 2 Indian Point 2 & 3 Takahama 1 Mihama 1* Tihange 1 North Anna 1 & 2 Turkey Point 3 & 4 Ohi 1 & 2 * The indicated plants have 14x14 guide tubes with gaps between the guide funnel and upper guide tube that will limit flange wear and prevent flange separation.  Therefore, the recommendations in this NSAL do not apply to these plants. ** The indicated plants have 14x14 guide tubes and gaps between the guide funnel and the upper guide tube which are nearly the same as the distance required for flange separation.

These kinds of things come from exceeding the plants useful life. Expect more of this in the future.  

This might force utilities to prematurely replace their heads. This is going to be enormously costly both in money and employee doses. 

When it comes to impairing capacity factor, these utilities guys would consume as much dose as needed without a conscience. If it comes to impairing profits, these guys will whine like little girls about consuming dose for their employees. In other words, their will defer maintenance and safety inspection because the radiation dose is too high for the risk.    

Subject: Thermal Sleeve Flange Wear Leads to Stuck Control Rod Number: NSAL-18-1 Basic Component: Thermal Sleeve in CRDM Reactor Head Penetration Date: July 9, 2018
Substantial Safety Hazard or Failure to Comply Pursuant to 10 CFR 21.21(a) Transfer of Information Pursuant to 10 CFR 21.21(b) Advisory Information Pursuant to 10 CFR 21.21(d)(2)
Yes  No   N/A  

SUMMARY In accordance with 10 CFR Part 21, Westinghouse reported an issue associated with thermal sleeve wear as a potential defect in May 2018 [1].  This NSAL provides details on the thermal sleeve flange issue to provide affected licensees a basis for operation and inspection recommendations. Operating experience (OE) has shown that for Westinghouse nuclear steam supply system (NSSS) plants that have thermal sleeves in the control rod drive mechanism (CRDM) penetration tubes, the wear of the thermal sleeve flange against the tube could have potential consequences that were not previously considered.  Recently, during a startup following a refueling outage at an Électricité de France (EdF) plant, Belleville Unit 2, a flange remnant from a separated thermal sleeve became cocked and interfered with control rod movement.  The previous safety evaluations of separated sleeves and flanges, in topical report PWROG-16003-P [2] and Technical Bulletin TB-07-2, Revision 3 [3] considered this interference to be unlikely based on the information that was available at that time.  Consequently, it was concluded that a stuck control rod was unlikely.  Considering the new OE from EdF [4], and the design similarities between the Belleville Unit 2 thermal sleeves and those used in Westinghouse NSSS plants and replacement reactor vessel heads, the inspection recommendations for thermal sleeve flanges in TB-07-2, Revision 3 may be insufficient.  While there have been no reported events of control rods failing to insert into the core when required, Westinghouse reported this issue to the NRC under 10 CFR Part 21 because it had the potential to create a substantial safety hazard.