ML13038A604

PIRT Item Summary

ML13038A604
Person / Time
Site:	Calvert Cliffs
Issue date:	01/24/2013
From:	- No Known Affiliation
To:	Nadiyah Morgan Plant Licensing Branch 1
Morgan N NRR/DORL/LPL1-1 301-415-1016
References
Download: ML13038A604 (6)

Text

Page 1 of 6 The Calvert Cliffs RI GSI-191 Chemical Effects Test Program has been developed in concert with the STP RI GSI-191 Chemical Effects Test Program. Calvert Cliffs has participated in STP and NRC interactions on the STP approach and has incorporated the agreements between the NRC staff and STP and most of the comments by the NRC staff on the STP approach.

We have categorized the 42 chemical effects PIRT items into four (4) categories as follows:

1. Those PIRT items that will be addressed specifically in the Calvert Cliffs integrated chemical effects test program similar to how STP addressed the item and which the NRC staff as agreed with this approach. We believe these items require very little further discussion.

2. Those PIRT items that will be addressed in the Calvert Cliffs integrated chemical effects test program similar to how STP addressed the item but we believe does require further discussion with the NRC staff.

3. Those PIRT items for which the approach for addressing may be considered unique and require discussion with the NRC staff.

4. Those PIRT items that we believe do not need to be addressed in the Calvert Cliffs chemical effects test program and the NRC agrees with this.

Calvert Cliffs believes that the proposed approach to addressing PIRT items categorized as both #1 and

1. 4 is resolved with the NRC staff and these issues can be removed from further discussion. We request the NRC staff to acknowledge agreement with this position and focus future discussion on the PIRT items categorized as #2 and #3. The 42 PIRT items are listed below in each of these categories.

1. Addressed by incorporating realistic conditions in the chemical effects test program.

a. Item 1.1: RCS coolant chemistry conditions at break

b. Item 1.2: pH Variability

c. Item 1.4: Containment spray CO2 scavenging and CO2/O2 air exchange

d. Item 1.5: Emergency Core Cooling System Injection of Boron

e. Item 2.1: Radiolytic Environment

f. Item 2.2: Radiological Effects: Corrosion Rate Changes

g. Item 2.4: Conversion of N2 to HNO3

h. Item 3.3: Debris Mix Particulate/Fiber Ratio

i.

Item 3.4: Effects of Dissolved Silica from Reactor Coolant System and Refueling Water Storage Tank

j.

Item 3.5: Containment Spray Transport

k. Item 3.6: Initial Debris Dissolution

l.

Item 3.7: Submerged Source Terms: Lead Shielding

m. Item 3.8: Submerged Source Terms: Copper

n. Item 3.10: Alloying Effects

o. Item 3.11: Advanced Metallic Corrosion Understanding

p. Item 4.2: Heat Exchanger: Solid Species Formation

q. Item 4.5: Coprecipitation

r. Item 5.1: Inorganic Agglomeration

Page 2 of 6

2. Addressed by incorporating realistic conditions in the chemical effects test program but requires discussion with NRC.

a. Item 6.2: Organic Agglomeration

b. Item 6.4: Coating Dissolution and Leaching

c. Item 7.2: Heat Exchanger: Deposition and Clogging

3. Approach to address requires discussion with NRC:

a. Item 2.5: Additional Debris Bed Chemical Reactions

b. Item 3.1: Crud Release

c. Item 3.12: Submerged Source Terms: Biological Growth in Debris Beds

d. Item 3.13: Reactor Core: Fuel Deposition Spall

e. Item 4.3: Reactor Core: Precipitation

f. Item 6.1: Break Proximity to Organic Sources

g. Item 7.3: Reactor Core: Fuel Deposition and Precipitation

4. No need to address in chemical effects test program

a. Item 1.3: Hydrogen Sources within Containment

b. Item 2.3: Hydrolysis

c. Item 3.2: Jet Impingement

d. Item 3.9: Concrete Material Aging

e. Item 4.1: Polymerization

f. Item 4.4: Particulate Nucleation Sites

g. Item 5.2: Deposition and Settling

h. Item 5.3: Quiescent Settling of Precipitate

i.

Item 5.4: Transport Phenomena: Precipitation and Coprecipitation

j.

Item 6.3: Organic Complexation

k. Item 7.1: Emergency Core Cooling System Pump: Seal Abrasion and Erosion or Corrosion

l.

Item 7.4: Reactor Core: Diminished Heat Transfer

m. Item 7.5: Reactor Core: Blocking of Flow Passages

n. Item 7.6: Reactor Core: Particulate Settling PIRT item categories 1, 2, and 3 are repeated below with a summary of the Calvert Cliffs proposed approach to addressing the item in the test program.

1. Addressed by incorporating realistic conditions in the chemical effects test program.

a. Item 1.1: RCS coolant chemistry conditions at break Long-term (30-day) tests will be run representing the bounding LOCA scenario that produces the largest quantity of debris. The quantities of materials in the test will be determined from the quantities of materials determined to be in the CCNPP containment for the bounding break, as determined by break modeling. The boron and lithium concentrations for each test will be selected by determining the concentrations in the RCS, RWST, and accumulators at CCNPP and calculating the concentration based on the contribution from each source for the LOCA scenario.

The boron and lithium contributions from the RCS will be based on time-averaged concentrations. The impact of higher and lower concentrations of boron and lithium on the pH

Page 3 of 6 of the system will be evaluated using chemical equilibrium modeling. If the modeling indicates that changes in solution chemistry cause deviations in pH that significantly affect corrosion or precipitation rates, bench-scale tests may be performed to investigate the rate of corrosion and extent of precipitation rates with higher or lower concentrations of boron and lithium. The temperature will be varied over the 30-day duration to match the temperature profile of the break scenario, with the exception that the effect of corrosion at temperatures higher than 190

°F will be addressed by autoclave testing as discussed in Section Error! Reference source not ound. of the main body of the paper.

b. Item 1.2: pH Variability The normal operating pH of the RCS at CCNPP is 7.1. The issue of pH variability over the fuel cycle is addressed by the selection of boron and lithium concentrations in Item 1.1.

c. Item 1.4: Containment spray CO2 scavenging and CO2/O2 air exchange The CCNPP chemical effects testing will be performed in a facility that is not air tight to ensure that potential formation of CaCO3 will be appropriately represented in the test conditions

d. Item 1.5: Emergency Core Cooling System Injection of Boron The concentration of boron to be used in the testing is addressed in Item 1.1.

e. Item 2.1: Radiolytic Environment A design calculation exists that computes the amount of acid that could be formed long-term at CCNPP. The quantity of acid determined in this calculation will be included in the chemical effects tests.

f. Item 2.2: Radiological Effects: Corrosion Rate Changes The addition of acid to the tests to simulate radiolysis is addressed in Item 2.1.

g. Item 2.4: Conversion of N2 to HNO3 The addition of acid to the tests to simulate radiolysis is addressed in Item 2.1.

h. Item 3.3: Debris Mix Particulate/Fiber Ratio The mixture of debris to be used in the tests is addressed in Item 1.1. The long-term tests will use a special debris bed with a pre-defined ratio of particles to fibers that will be used as a head loss detection instrument to assess the relative impact of chemical effects under a standardized condition.

i.

Item 3.4: Effects of Dissolved Silica from Reactor Coolant System and Refueling Water Storage Tank The quantity of silica present in the RCS, RWST, and accumulators at CCNPP will be evaluated along with the boron and lithium as described in Item 1.1, and the contribution of silica from each source during each test will be calculated and added at the beginning of the test as described for boron and lithium in Item 1.1.

j.

Item 3.5: Containment Spray Transport CCNPP prepared conservative debris generation and transport calculations that specifically addressed latent debris, corrosion products, insulation materials, and coating debris. The

Page 4 of 6 results of the conservative debris generation and transport calculations will be addressed in the CCNPP chemical effects testing and analysis. Also, the corrosion of materials exposed to containment spray above the pool will be accounted for in the chemical effects tests.

k. Item 3.6: Initial Debris Dissolution The relevant materials and debris determined to be present at CCNPP and contribute to chemical effects will be included in the test loop at the beginning of each test.

Determination of the quantities of debris is addressed in Item 1.1.

l.

Item 3.7: Submerged Source Terms: Lead Shielding An evaluation of the sources of lead in containment at CCNPP will be performed to determine whether there is a potential for significant lead quantities to be released into solution. If so, it may be necessary to include lead in the chemical effects tests.

Determination of the quantity of lead debris is addressed in Item 1.1.

m. Item 3.8: Submerged Source Terms: Copper An evaluation of the sources of copper and zinc in containment at CCNPP will be performed to determine whether there is a potential for significant quantities of these metals to be released into solution. If so, it may be necessary to include copper and/or zinc in the chemical effects tests. Determination of the quantity of copper and zinc is addressed in Item 1.1.

n. Item 3.10: Alloying Effects Appropriate surrogate materials will be selected for the chemical effects tests.

o. Item 3.11: Advanced Metallic Corrosion Understanding Appropriate synergistic effects and corrosion inhibition are addressed due to the selection of materials in the proper proportions relative to the CCNPP containment, as described in Item 1.1. Acid formation is addressed in Item 2.1.

p. Item 4.2: Heat Exchanger: Solid Species Formation The final portion of the tests will be used to investigate low temperature chemical effects by reducing the temperature in stages until room temperature is achieved.

q. Item 4.5: Coprecipitation The issue of coprecipitation is addressed by inclusion of all materials that participate in chemical reactions in the same proportions that they are present at CCNPP, as described in Item 1.1.

r. Item 5.1: Inorganic Agglomeration No attempt to either stimulate or prevent agglomeration of particles will be incorporated into the chemical effects tests. In the chemical effects tests, particulate debris will be pre-deposited in the debris beds and will not be circulating in the solution in significant quantities. The solution chemistry in the chemical effects tests will be similar to the CCNPP system, so the formation and behavior of chemical precipitates will be similar, with particulate debris already present in the debris bed.

Page 5 of 6

2. Addressed by incorporating realistic conditions in the chemical effects test program but requires discussion with NRC.

a. Item 6.2: Organic Agglomeration No attempt to either stimulate or prevent agglomeration of particles will be incorporated into the chemical effects tests. In the chemical effects tests, particulate debris will be pre-deposited in the debris beds and will not be circulating in the solution in significant quantities. The solution chemistry in the chemical effects tests will be similar to the CCNPP system, so the formation and behavior of chemical precipitates will be similar, with particulate debris already present in the debris bed. See Item 5.1.

b. Item 6.4: Coating Dissolution and Leaching Coating dissolution and leaching will be addressed by including scaled surface areas of coupons coated with CCNPP-specific qualified and unqualified coatings in the test chamber.

c. Item 7.2: Heat Exchanger: Deposition and Clogging The efficiency of heat exchange and performance of the heat exchangers will not be monitored during the chemical effects tests. However, if the heat exchanger used in the test can be disassembled, the heat exchanger tubes will be visually inspected for the presence of precipitates or scale formation, and if precipitates or scale is present, a sample of the precipitates will be scraped from the surfaces and analyzed using the techniques used for precipitate analysis.

3. Approach to address requires discussion with NRC:

a. Item 2.5: Additional Debris Bed Chemical Reactions The CCNPP PRA model will be queried to determine the percentage of HELB initiating events that result in core damage. If the percentage of these events is significant, the chemical effects of radiation degradation of unqualified coatings will be investigated. If the percentage of these events is insignificant, no additional evaluation is required as the radiation levels during non-core damage events is not expected to be high.

b. Item 3.1: Crud Release STP performed an evaluation of crud release due to the thermal and hydraulic shock of a LOCA and determined the quantity of crud released would be on the order of 25 lbs which is less than the assumed latent debris particulate load. Crud release will not be addressed in the chemical effects tests. The crud is a source term for particulate debris and is not expected to affect the chemical environment.

c. Item 3.12: Submerged Source Terms: Biological Growth in Debris Beds CCNPP inspected the containment sumps and observed no biologic growth. One of the radiation protection individuals at CCNPP has inspected containment sumps at multiple plants and cleaned two of them. In none of these cases was biologic growth observed. This item will not be addressed in chemical effects tests.

d. Item 3.13: Reactor Core: Fuel Deposition Spall

Page 6 of 6 The effects of chemical precipitation on the fuel rods have been previously addressed in a conservative manner for CCNPP using the LOCADM software. Precipitation of materials with retrograde solubility in the bulk solution within the reactor core will be addressed in bench-scale tests based on the concentration, core temperature, and solubility limit for potential precipitates.

e. Item 4.3: Reactor Core: Precipitation An investigation of existing literature will be performed to evaluate the possible effects of retrograde solubility, and thermodynamic software may be used to identify possible species that may exhibit retrograde solubility. In addition, this item may be explored in bench-scale testing.

f. Item 6.1: Break Proximity to Organic Sources The cases where a significant quantity of oil would be introduced to the containment pool would be limited to a few larger breaks in the vicinity of one of the RCP motors. Since the majority of break cases would not have significant quantities of oil, oil will not be included in the 30-day chemical effects tests. The issue of organic materials from coatings failure and organic binders in insulation debris is addressed in Item 6.4.

g. Item 7.3: Reactor Core: Fuel Deposition and Precipitation The resolution for this item is the same as the resolution for Item 3.13 and Item 4.3.