Bulletin 79-15: Deep Draft Pump Deficiencies

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

                               July 11, 1979  

                                             IE Bulletin No. 79-15 

DEEP DRAFT PUMP DEFICIENCIES 

Description of Circumstances:  

On October 20, 1978, Commonwealth Edison Company reported that manufacturing
deficiencies had been identified in new high pressure core spray, low 
pressure core spray, and residual heat removal pumps manufactured by 
Ingersoll-Rand (I-R) Company, Cameron Pump Division. 

Each of these pumps is a vertical turbine pump with impellers located in 
bowls in a sump or a self contained barrel. The motor (prime mover) is 
located at the highest pump elevation to take into account maximum flooding 
at the site or space considerations. The suction is at the lower end of the 
pump while the discharge head is just below the driver. Bearings supporting 
the vertical shaft segments (usually 5 to 10 segments) are either self 
lubricated, force fed (lubricated by fluid being pumped), or oil lubricated 
and maintained within their own isolated system. These pumps are designated 
as "Deep Draft". Figures 1&2 show typical outlines of such pumps. 

The internal deficiencies, identified through dimensional and visual 
inspections were as follows: 

Low Pressure Core Spray Pumps (I-R Model No. 29APKD-5) (Date of Manufacture 
- February 1973) 

.    Loose impeller bolts and bolts improperly staked 
.    Loose key - keyway fit 
.    Excessive runout on pump shaft 
.    Bearing showed wear  
.    Bearing clearance exceeded recommended tolerance 
.    Coupling thread galled 
.    Wear ring clearance out-of-specification 
.    Impeller-to-shaft clearance out of specification 
.    Cracks found in second-and-third-stage impellers 
.    Stuffing box bushings were severely galled 

High Pressure Core Spray Pumps (I-R Model No. 12X20KD) (Date of Manufacture 
- September 1972) 

.    Bearing clearance exceeded recommended tolerance 
.    Wear ring clearance out-of-specification 
.    Bearings showed wear 
.

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                                                            Page 2 of 3 

.    Bearing loose in casing 
.    Excessive runout on pump shaft 
.    Wear ring lock screws missing on eighth stage 
.    Shrink fit bearing came out of casing during pump shaft removal - 
     casing sleeve socket found to be egg shaped 

Residual Heat Removal Pumps (I-R Model No. 29APKD-3) (Date of Manufacture 
December 1972) 

.    Loose impeller bolts and bolts not properly staked 
.    Excessive runout on pump shaft 
.    Bearing found cracked 
.    Bearing clearance out-of-specification 
.    Couplings cut because galling prevented disassembly 
.    Wear ring clearance out-of-specification 

The above deficiencies were identified at a facility under construction. In 
1978, similar deficiencies in deep draft pumps were identified at three 
other facilities (North Anna 1 & 2, Surry 1 & 2, Beaver Valley 1). Problems 
with these pumps involved design and workmanship deficiencies which required
extensive inspection, replacement of parts and major redesign. The 
manufacturers involved in these cases were Ingersoll-Rand, 
Bingham-Willamette and Byron Jackson. Some of the measures taken to assure 
pump operability at these locations included: 

1. Pump shaft bearing redesign 

2. Column redesign (stiffening) to improve vibration response 

3. Upgraded pump alignment procedures 

4. Pump fluid inlet condition reevaluation and redesign 

5. Extensive testing 

The observed deficiencies spanning the past 1 1/2 years indicate that pumps 
of this class may not be sufficiently reliable particularly when utilized in
ECCS and RHR applications where long tem cooling capability is required 
following a LOCA or similar event. 

Action to be Taken by Licensees and Permit Holders: 

All holders of reactor operating licenses and construction permits shall 
provide the following information within 60 days of this letter. 

1.   The number of deep draft pumps similar to those shown in Figures 1 and 
     2 utilized in safety related applications in each facility. 

2.   Manufacturer, model, capacity and plant application. 
.

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3.   Overall dimensions of pumps. 

4.   Summary of startup, testing and routine maintenance history. 

5.   Operational problems and major repair efforts. 

6.   The longest interval that each pump has been available for operation 
     without corrective maintenance. Identify the number of cycles of opera-
     tion during this interval, the duration of each cycle and the operating
     mode(s) (recirculation, rated flow, etc.). Identify the longest con-
     tinuous operation at or near rated flow conditions for each pump and 
     the status of the pump operability at the end of the run. 

In addition licensees shall accumulate and make available for inspection at 
the licensees plant site the following information on the above identified 
pumps. 

1.   Drawings, sectional assemblies and parts list. 

2.   Detailed history of pump maintenance (alignment, parts replacement, 
     etc) including bearing wear data, replacement frequency and a 
     comparison with the manufacturers rated life for wearing surfaces. 

3.   Quality assurance and reliability testing requirements.  

4.   Design specifications 

5.   Results of tests performed during operation or prior to licensing. 

6.   Details of the procedures used to align the pump column. 

For those cases where the maintenance or operating history of a particular 
pump indicates that the design specifications are not being met, initiate 
appropriate actions that will demonstrate conformance to design 
requirements. Provide a description of planned actions within 60 days 
including a schedule for implementation of any actions that will not be 
completed within 120 days. In addition describe any planned or completed 
tests involving long tem operation of prototypes or pumps of similar design, 
which demonstrate the long term operability of such deep draft pumps at your 
facility. 

Approved by GAO, B180225 (R0072), clearance expires 7/31/80. Approval was 
given under a blanket clearance specifically for identified generic 
problems. 

Enclosure: 
Figures 1 and 2