EPRI Innovators
IN-114722
DECONTAMINATING, REFURBISHING, AND REUSE OF SAFETY RELATED CENTRIFUGAL CHARGING / HIGH HEAD SAFETY INJECTION PUMPS FOR PWR PLANTS
Southern Nuclear, in 1997, began investigating and pursuing alternatives to make reliability improvements to their centrifugal charging / high head safety injection pumps. Their objective being to reduce the cost associated with upgrading the shaft material, critical component fits, and performance improvements. SNC made a decision to pursue decontamination and restoration of the rotating elements based on a partnership between HydroAire, In., and Alaron Corp. The EPRI "DFD Lite" process utilized by Alaron allowed the contaminated pump element (i.e., shaft, impellers, diffusers, pressure reducing sleeve, etc.) to be free-released such that HydroAire could recondition the components, incorporating the upgrades and performance improvements requested by SNC. Development of this alternative has created a competitive market, improved pump element quality, and opened up other opportunities for contaminated pump repair.
| "Traditionally, new rotating elements would have been required to implement the reliability improvements we desired. The "DFD Lite" process provided a repair alternative and
created a competitive market not previously available, resulting in significant cost savings for SNC." - Kevin Glandon, Southern Nuclear "Contaminated pump repair / refurbishment using the "DFD Lite" process has improved the quality of repair / replacement costs, and increased design knowledge of these pumps not only for the Southern Company, but for the industry." - Will Gates, Southern Company Generation |
BENEFITS
Decontamination using the EPRI "DFD Lite" process enabled charging pump elements to be free released for repair, refurbishment, and performance testing. These steps enabled the utility to avoid the purchase of replacement rotating elements, and redice the inventory of contaminated material while avoiding disposal of the pump element as low level radioactive waste.
CHALLENGES
The conditions in the primary circuit of a PWR can place significant demands in critical components, which lead to their degredation and also to their contamination due to the deposition of activated corrosion products. If degredated components cannot be repaired to their original configuration, they must be disposed of as low level waste. Tequniques were needed to repair /refurbish degraded components to permit their continued use.
RESPONSE
A 2½" RL-1J charging pump element from the Vogtle Electric Generating Plant (PWR) was removed from service for refurbishment, testing, and shaft material upgrade. HydroAire, an independent pump repair company, was contracted to perform the services. Due to the requirement to test the pump element and there being no contaminated pump test loops in the country, decontamination to free release was required. Alaron Corporation was contracted to perform the decontamination services.
Alaron employed a modified version of the EPRI DFD process, designated "DFD Lite," to obtain free release of the pump components. "DFD Lite" removes contamination from the 400 series stainless steel used in pump impellers and casings in a slow and controlled manner. The pump was s successfully decontaminated to free release levels, therby permitting the untility to engage the services of an alternative to the "hot shop" operated by the original equipment manufacturer (OEM).
HydroAire provided services that included repair / refurbishment of reclaimed components, manufacture of consumable or unusable parts, performance testing, detailed dimensional analuses, and enginerring design. Following refinement of the processes, performance curves obtained after the refurbishing operation showed the pump met all the stringent plant operating requirements.
CALCULATED VALUE OF APPLICATION
Prior to the EPRI "DFD Lite" process, the only option available to nuclear utilities for a replacement charging pump element with certified performance curves was to buy a new element from the OEM. The cost savings of the pump repair alternative created by the "DFD Lite" process for Southern Nuclear has been summarized below. Table 1 represents the approximate SNC cost that would have been incurred if "DFD Lite" and the partnership between HydroAire and Alaron had not been available.
| Table 1: Approximate Cost without "DFD Lite" | |||
|---|---|---|---|
| Year |
Refurbished Element w/ Test |
Rad. Waste Disposal |
Total |
| 1997 (1 pump) |
$800,000 | $50,000 | $850,000 |
| 1998 (2 pumps) |
$1,600,000 | $50,000 | $1,650,000 |
| 1999 (3 pumps) |
$800,000 | $50,000 | $850,000 | Total | $3,200,000 | $150,000 | $3,350,000 |
After the first charging pump was succesfully decontaminated to free release, repaired and returned to service at the plant site, a complete market was created for SNC. Additional refinements to the HydroAire and Alaron processes were needed to improve and expand the alternative to the industry. The approximate SNC cost for accomplishing the same pump element rotation after working with HydroAire and Alaron to develop this alternative is summarized in Table 2.
| Table 2: Approximate Cost with "DFD Lite" | |||
|---|---|---|---|
| Year |
Refurbished Element w/ Test |
Rad. Waste Disposal |
Total |
| 1997 (1 pump) |
$150,000 | $0 | $150,000 |
| 1998 (2 pumps) |
$490,000 | $0 | $490,000 |
| 1999 (3 pumps) |
$325,000 | $0 | $325,000 | Total | $965,000 | $0 | $965,000 |
The "DFD Lite" decontamination process and development of a competitive alternative process and development of a competitive alternative resulted in an approximate cost saving of $2,385,00 for Southern Nuclear. SNC has a total of ten Model 2½ RL-1J pumps between Plants Farley and Vogtle.
Southern Nuclear's willingness to invest and work with these two companies to develop and refine a repair alternative has resulted in significant savings. At last check, other utilities are now sharing the benefit of this alternative.
REFERENCES
Review of Experience with the EPRI DFD Pocess, TR-109036, December 1998.
EPRI reports are available from the EPRI Distribution Center:
(510)934-4212
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For further information, contact:
- Electric Power Research Institute
P.O. Box 10412
Palo Alto, CA. 94303
- Howard Ocken, Project Manager (650)855-2055
- Christopher J. Wood, Target Leader (650)855-2379
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INTEREST CATEGORIES
- Radiation Exposure Management
- Equipment Assessment & Maintenance Technologies
- Repair & Replacement Application Center