DL/T 771-2014Guideline for the selection of ion exchange resins used in power plant water treatment systems (English PDF)

4.1 Principles for resin selection

4.1.1 Makeup water treatment

For makeup water treatment systems in thermal and nuclear power plants, weak-acid, strong-acid, weak-base, or strong-base resins may be selected based on the characteristics of the source water and the specific features of the ion exchange demineralization units employed.

4.1.2 Condensate polishing

For ion exchange units in the secondary-side condensate polishing systems of thermal and nuclear power plants, strong-acid and strong-base resins should be used.

4.1.3 Water treatment for nuclear power plant's primary circuits and auxiliary

systems

For systems requiring high resin exchange capacity, gel-type nuclear-grade resins should be used; for purification systems requiring high particle adsorption and filtration capabilities, macro-porous nuclear-grade resins should be used.

4.1.4 Circulating cooling water treatment

For ion exchange units used in makeup water treatment and side-stream purification for circulating cooling water systems, weak-acid cation resins should be selected.

4.1.5 Generator internal cooling water treatment

For ion exchangers treating generator internal cooling water, strong-acid and strong- base resins should be used.

4.2 Selection of make-up resin

When replenishing resin for ion-exchange water treatment equipment, it should select resin of the same designation and from the same manufacturer as that currently in use.

If this is not possible, the replacement resin should have technical specifications, such as exchange capacity, physical and chemical stability, uniformity coefficient, that are not inferior to the original resin, meanwhile its other basic performance indicators shall be substantially similar to those of the original resin.

4.3 Selection of resin ionic form

4.3.1 For make-up water treatment systems, the ionic form of the resin should be the standard form. sodium form for strong-acid cation resins, chloride form for strong-base anion resins, hydrogen form for weak-acid cation resins, free-amine form for weak- base anion resins.

4.3.2 For condensate polishing systems in nuclear power plants, strong-acid cation

resins should be in the hydrogen form, strong-base anion resins should be in the hydroxide form.

4.3.3 For water treatment systems serving the primary circuit and auxiliary systems of

nuclear power plants, nuclear-grade resins should be selected. These may be in the hydrogen, lithium, potassium, or hydroxide forms, or in mixed forms such as hydrogen/hydroxide, lithium/hydroxide, or potassium/hydroxide.

4.3.4 For generator internal cooling water treatment systems, strong-acid cation resins

should be in the hydrogen or sodium form, strong-base anion resins should be in the hydroxide form.

Note. When determining the order quantity for resin, the impact of volume changes, which are caused by ionic form conversion during resin regeneration and exchanger operation, on the procurement volume shall be taken into account. The resin conversion expansion rate shall be determined in accordance with the method specified in GB/T 11991.

5.1 For the cation and anion beds in the primary demineralization ion-exchange units

of make-up water treatment systems, it should use 001×7 strong-acid cation resin and

201×7 or 201×4 strong-base anion resin.

5.2 For mixed-bed units in makeup water treatment systems, it should use 001×7MB strong-acid cation resin and 201×7MB strong-base anion resin; alternatively, high- strength D001 and D201 resins or gel-type uniform-particle-size resins may be used.

5.3 The strong-acid cation resin and strong-base anion resin used in the mixed bed need not both be of the macro-porous type or both of the gel type.

5.4 When a mixed-bed unit is not installed downstream of the primary demineralization system, it should use Type I strong-base anion resin for the anion exchange bed.

5.5 Acrylic-based strong-base anion resins should not be used, when the water temperature in the treatment system exceeds 35 °C.

5.6 Resins from other brands may also be used in makeup water treatment systems, provided their physicochemical and operational performance indicators meet the technical requirements of the respective water treatment units.

6.1 Basic requirements

6.1.1 Macro-porous strong-acid cation and strong-base anion resins used in condensate

polishing mixed beds shall comply with the requirements for D001MBP and D201MBP specified in DL/T 519-2014.

6.1.2 Macro-porous strong-acid cation and strong-base anion resins used in separate

cation and anion beds (arranged in series) for condensate polishing shall comply with the requirements for D001P and D201P specified in DL/T 519-2014.

6.1.3 For gel-type strong-acid cation and strong-base anion resins used in condensate

polishing mixed beds, the uniformity coefficient shall not exceed 1.3; the strength shall comply with the technical requirements for 001MBP and 201MBP specified in DL/T

519-2014; other indicators shall comply with the requirements for 001×7MBP and

201×7MBP specified in DL/T 519-2014.

6.1.4 For cation and anion exchange beds in a series single-bed condensate polishing

system, gel-type strong-acid and strong-base resins shall be used. Their strength shall meet the requirements for 001P or 201P resins specified in DL/T 519-2014; other parameters shall comply with the technical requirements for 001×7P and 201×7P resins specified in DL/T 519-2014.

6.1.5 Condensate polishing systems may also utilize resins from other brands, provided their physicochemical and operational performance parameters meet the technical requirements of the respective water treatment units.

6.2 Technical requirements for operational performance

6.2.1 Spherical bead percentage after attrition

For resins used in series single-bed and mixed-bed systems that undergo external regeneration, the spherical bead percentage after attrition shall be no less than 90%. For pre-treatment cation exchange bed resins used in the secondary circuit condensate treatment of nuclear power plants, the spherical bead percentage after attrition shall be no less than 95%. The spherical bead percentage after attrition shall be determined in accordance with GB/T 12598.

6.2.2 Organic leachable

Resins with low organic leachable content shall be selected for condensate polishing systems. For resins used in the condensate polishing of thermal power plants and nuclear power plant secondary circuits, the organic leachable content of sodium-form

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