US4042455A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for dissolving radioactive corrosion products from internal surfaces of a nuclear reactor
Assignee: Westinghouse Electric Corp
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Filing: 1975-05-08
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Granted: 1977-08-16
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Expires: 1995-05-08
Abstract
Abstract A process for dissolving radioactive corrosion products from the internal surfaces of a nuclear reactor. In preparation for reactor refueling, the reactor coolant is depressurized and the temperature reduced to ˜140° F. Hydrogen is purged from the system and the coolant repressurized to about 400 psi to permit operation of a reactor coolant circulating pump. A solution containing oxygen, preferably hydrogen peroxide, is injected into the reactor coolant which is then circulated through the reactor. The thus oxygenated coolant effects prompt and nearly complete release, at least 95% complete, of radioactive corrosion products, especially cobalt 58, from the reactor internal surfaces. The coolant is then circulated through a demineralizer which removes such products by ion exchange processes, at the completion of which, the reactor is opened to commence replacing fuel assemblies in the reactor.
Inventors
- 👤 William W. Brown
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 21:39
CPC Classifications
G; G21; G21C; G21C19/00; G21C19/28; G21C19/30; Y; Y02; Y02E; Y02E30/00; Y02E30/30
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
158 words
The process for dissolving radioactive corrosion products from the internal surfaces of a nuclear reactor comprising the steps of: reducing the pressure and temperature of coolant circulating in a closed nuclear reactor steam supply system to about atmospheric pressure and 140° F. respectively; continuing the circulation of said coolant to permit the release of fission gases and fission products into the circulating coolant and until the hydrogen concentration in the coolant is reduced to less than about 4 cc per kg; increasing the pressure of said coolant to several atmospheres of pressure; adding a solution having an oxygen content greater than water to said circulating coolant to further cause the release of radioactive products from the reactor internal surfaces into said coolant; reducing the pressure of the circulating coolant to atmospheric pressure; passing said coolant containing said radioactive products through a demineralizer to remove said products; and returning the thus decontaminated coolant to the reactor steam supply system.
Claim 2
Dependent Claim
158 words
The process for dissolving radioactive corrosion products from the internal surfaces of a nuclear reactor comprising the steps of: reducing the pressure and temperature of coolant circulating in a closed nuclear reactor steam supply system to about atmospheric pressure and 140° F. respectively; continuing the circulation of said coolant to permit the release of fission gases and fission products into the circulating coolant and until the hydrogen concentration in the coolant is reduced to less than about 4 cc per kg; increasing the pressure of said coolant to several atmospheres of pressure; adding a solution having an oxygen content greater than water to said circulating coolant to further cause the release of radioactive products from the reactor internal surfaces into said coolant; reducing the pressure of the circulating coolant to atmospheric pressure; passing said coolant containing said radioactive products through a demineralizer to remove said products; and returning the thus decontaminated coolant to the reactor steam supply system.
Claim 3
Dependent Claim
15 words
The process according to claim 1 wherein said oxygen solution consists essentially of hydrogen peroxide.
Claim 4
Dependent Claim
22 words
The process according to claim 2 wherein said radioactive products consist essentially of cobalt 58, cobalt 60, manganese 54 and molybdenum 99.
Claim 5
Dependent Claim
173 words
The process for dissolving radioactive corrosion products from the internal surfaces of a nuclear reactor comprising the steps of: reducing the pressure and temperature of coolant circulating in a closed nuclear reactor steam supply system having a coolant capacity of about 9600 cubic feet to about 400° psi and 140° F. respectively; adding a water solution of hydrogen peroxide at the rate of 0.5 gpm to a reactor charging flow of about 100 gpm, and pumping said circulating coolant to provide a concentration of about 300 ppm at the point of injection to the circulating coolant, and continuing injection of hydrogen peroxide until a residual of 2 ppm H 2 O 2 is obtained in the entire circulating coolant in the reactor system, thereby effecting the release of radioactive products from the reactor internal surfaces into said coolant; reducing the pressure of the circulating coolant to atmospheric pressure; passing said coolant containing said radioactive products through demineralizing apparatus to remove said products; and returning the thus decontaminated coolant to the reactor coolant system.
Claim 6
Dependent Claim
173 words
The process for dissolving radioactive corrosion products from the internal surfaces of a nuclear reactor comprising the steps of: reducing the pressure and temperature of coolant circulating in a closed nuclear reactor steam supply system having a coolant capacity of about 9600 cubic feet to about 400° psi and 140° F. respectively; adding a water solution of hydrogen peroxide at the rate of 0.5 gpm to a reactor charging flow of about 100 gpm, and pumping said circulating coolant to provide a concentration of about 300 ppm at the point of injection to the circulating coolant, and continuing injection of hydrogen peroxide until a residual of 2 ppm H 2 O 2 is obtained in the entire circulating coolant in the reactor system, thereby effecting the release of radioactive products from the reactor internal surfaces into said coolant; reducing the pressure of the circulating coolant to atmospheric pressure; passing said coolant containing said radioactive products through demineralizing apparatus to remove said products; and returning the thus decontaminated coolant to the reactor coolant system.
Claim 7
Dependent Claim
27 words
The process according to claim 1 including the step of continuing to add said solution until the residual concentration thereof in said coolant is about 2 ppm.
References Cited (Backward Citations)
US3663725A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-08-15 | 1981-02-14 | 1981-08-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-08-15 | 1985-02-14 | 1985-08-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-08-15 | 1989-02-14 | 1989-08-16 | $7700.00 | Window Closed / Lapsed |