United States Nuclear Regulatory Commission - Protecting People and the Environment

IE Circular No. 78-12 - HPCI Turbine Control Valve Lift Rod Bending


CR78012 

                               UNITED STATES 
                      NUCLEAR REGULATORY COMMISSION 
                         WASHINGTON, D. C. 20555 

                              June 29, 1978 

MEMORANDUM FOR:     B. H. Grier, Director, Region I 
                    J. P. O'Reilly, Director, Region II 
                    J. G. Keppler, Director, Region III 
                    K. V. Seyfrit, Director, Region IV 
                    R. H. Engelken, Director, Region V 

FROM:               Norman C. Moseley, Director, Division of Reactor 
                      Operations Inspection, Office of Inspection and 
                      Enforcement 

SUBJECT:            IE CIRCULAR 78-12 - HPCI TURBINE CONTROL VALVE LIFT
					ROD BENDING 

     The subject circular is transmitted for issuance no later than the 
close of business on June 30, 1978. The circular should be issued to all 
holders of BWR Operating Licenses or Construction Permits excepting those 
listed in Enclosure 2. Also enclosed is a draft copy of the transmittal 
letter. 


                                        Norman C. Moseley, Director 
                                        Division of Reactor Operations 
                                          Inspection 
                                        Office of Inspection and Enforcement

Enclosures: 
1.  Draft Transmittal Letter 
2.  List of Non-Applicable 
      BWR Plants 
3.  IE Circular 78-12 

CONTACT:  C. J. DeBevec, IE 
          49-28180 
.

(Transmittal letter for IE Circular 78-12, to each holder of a BWR Operating
License or Construction Permit excepting to those listed as non-applicable 
BWR plants) 

Addressee: 

The enclosed IE Circular No. 78-12, is forwarded to you for information. No 
written response is required. Should you have any questions related to your 
understanding of this matter, please contact this office. 

                                        Sincerely, 


                                        Signature 
                                        (Regional Director) 

Enclosures: 
1.  IE Circular No. 78-12 
2.  List of IE-Circulars 
      Issued for 1978 
.

List of Non-Applicable BWR Plants 

The BWR plants listed below do not have a HPCI system or if they have a HPCI
system they use a different steam turbine. For these reasons the enclosed 
Circular should not be issued to the licensees of these plants. 

Plants in Region I 
Millstone Unit No. 1 
Nine Mile Point Unit No. 1 
Oyster Creek 

Plants in Region III 
Big Rock Point 
Dresden Unit Nos. 1, 2 and 3 
La Crosse 
Quad Cities Unit Nos. 1 and 2 

Plant in Region V 
Humboldt Bay  
.

                             UNITED STATES 
                      NUCLEAR REGULATORY COMMISSION 
                   OFFICE OF INSPECTION AND ENFORCEMENT 
                          WASHINGTON D. C. 20555 

                              June 30, 1978 

                                                     IE Circular No. 78-12 

HPCI TURBINE CONTROL VALVE LIFT ROD BENDING 

In March 1977, during routine surveillance testing of the High Pressure 
Coolant Injection (HPCI) system at Cooper Nuclear Station, it was found that
the minimum turbine speed attainable via control valve regulation by the 
speed governor was 4000 rpm. This indicated that the control valves were 
remaining partially open even though the control system was sending a shut 
signal. The HPCI turbine is manufactured by the Terry Steam Turbine Company.

Investigation revealed that the control valve lift rods were bent. The 
initial cause was thought to be improper linkage length adjustments causing 
positive overtravel in the closed position. Subsequent review, while not 
discounting the previous conclusions, determined that the bending may have 
resulted from binding due to scale or rust buildup on the rods. The control 
valve lift rods have a series of circumferential reliefs for steam leakage 
control. Material wedging between the rod relief area and the rod bushing in
the steam chest could cause momentary seizure and bending of the lift rods 
during the rapid closure action associated with a quick start. 

Subsequent to this event a review was made to determine the extent of a 
possible generic problem in the area. It was determined that the problem 
affects only the HPCI turbine with its multiple control valves; other 
applications using Terry Turbines, as in the Reactor Core Isolation Cooling 
System (RCIC) in BWRs and the Auxiliary Feedwater Pump in PWRs, are not 
affected since they incorporate a different control system. 

During the review, GE representatives were consulted and it was learned that
bent lift rods had been reported at four operating BWRs. In response, GE 
issued Service Information Letter (SIL) No. 223, dated July 8, 1977 and 
associated instruction/drawing sheets to GE nuclear power facilities having 
HPCI turbines. That SIL together with the instruction/drawing sheets 
identified the control valve lift rod problem and the recommended corrective
action. The recommended action by GE for BWR facilities with a HPCI turbine 
as set forth in the SIL is quoted as follows: 

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IE Circular No. 78-12                                      June 30, 1978 

     "1.  Examine the control valve linkage assembly for any evidence of 
          binding, rust or scale accumulation. Examine the lift rod for 
          evidence of bending. Damaged lift rods should be replaced. Do not 
          attempt to rework or straighten. 

     "2.  Verify proper control valve linkage lengths as defined on the 
          lever diagram contained in Section 9 of your HPCI Terry turbine 
          instruction manual. These measures should be taken with the 
          turbine in the cold condition. 
          
     "3.  Exercise the control valve linkage on a weekly basis, either 
          manually or by starting the auxiliary oil pump, and verify total 
          valve travel and freedom of movement. 

     "Immediately report any abnormal conditions noted in the above checks 
      to your local General Electric service representative. 

     "In addition, General Electric recommends that BWR operators install a 
      linkage modification which will reduce the bending movement on the 
      lift rods during opening and closing cycles. The hardware and an FDI 
      detailing installation instructions will be made available at no 
      charge in approximately 3 months. Following installation and check out 
      of this modification, the weekly check (item 3 above) may be 
      discontinued." 

All holders of boiling water reactor operating licenses or construction 
permits for facilities with a HPCI Terry Turbine should be aware of the 
possibility of a scale or corrosion product buildup in the steam chest 
bushing area and possible lift rod seizure. The information and 
recommendation provided by General Electric should be referred to for 
appropriate corrective action. 

No written response to this Circular is required. If you require additional 
information regarding this matter, contact the Director of the appropriate 
NRC Regional Office. 

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