ML032030535

From kanterella
Jump to navigation Jump to search
PWR Sump Performance Evaluation Methodology: Velocity Calculation, Draft, Attachment 4
ML032030535
Person / Time
Issue date: 06/21/2003
From:
Office of Nuclear Reactor Regulation
To:
Shared Package
ML032060420 List:
References
+KBR1SISP20050504, GSI-191, TAC MA6454
Download: ML032030535 (6)
v • d • e


Text

DRAFT June 21, 2003 PWR Sump Performance Evaluation Methodology:

Velocity Calculation Guidance:

To determine the transportability of debris, the velocity distribution of the liquid on the containment floor must be calculated. Two methods of performing this calculation are presented.

Simple Approach:

Using an electrical circuit analogy, the bulk velocity of liquid moving across the containment floor in discrete paths or channels may be calculated using a nodal network. The procedure for accomplishing this is as follows:

1.) The containment is segregated into discrete flow paths.

1.1) Each flow path should have relatively constant hydraulic characteristics along the path length.

1.2) A "node" is defined as the junction of two or more flow paths.

1.3) Flow paths are connected or joined by nodes.

1.4) The sump represents a terminal or "sink" node in the network.

1.5) The break represents a supply or "source" node in the network.

1.6) The source node may be moved to represent different break locations.

1.7) Depending upon flow paths from the upper containment to the sump floor region, other supply or "source" nodes may be identified and located in the network.

1.8) It is suggested that abrupt changes in hydraulic characteristics (specifically, abrupt changes in flow area) be treated by creating two flow paths connected by a node at the abrupt hydraulic change.

2.) Using reference manuals (such as I'delchek) and standard hydraulic practices, the hydraulic characteristics of each flow path are evaluated.

2.1) Characteristic hydraulic length 2.2) Characteristic hydraulic flow area 2.3) Hydraulic loss coefficients for the entrance and exit of flow path in the network 2.4) Select an appropriate correlation to represent the frictional losses associated with each characteristic hydraulic length. The correlation will be determined by surface roughness, etc.

3.) Several options exist for solving the hydraulic network to calculate bulk fluid velocities.

3.1) First, a nodal network code may be applied to calculate bulk velocities 3.2) Second, the network equations may be entered into an engineering calculation software package, such as TkSolver and the software allowed to operate on the system of equations to obtain a solution.

Velocity_Calculation_Guide_R1.doc 1

DRAFT June 21, 2003 3.3) A third solution is to enter the equations into a spreadsheet and solve them in an iterative manner.

4.) A sensitivity evaluation on fluid velocities and associated debris transport should be performed with the nodal network by varying the hydraulic parameters of the network.

Based on the uncertainties typically associated with hydraulic loss coefficients and friction pressure drop correlations, a variation of +/- 20 on the hydraulic parameters input to the fluid velocity calculation recommended.

Once the velocities in the network are solved for, an assessment of debris transport may be made as described below. This approach provides for the calculation of the bulk fluid velocity in each flow path about the containment floor.

Detailed Approach:

A detailed calculation of the flow patterns in the liquid pool on the containment floor may be calculated using a computational fluid dynamics (CFD) code. The model is constructed using detailed containment geometry information. This approach provides for detailed local fluid velocities throughout the model region.

Debris Transport Assessment:

The velocities calculated from one of the two methods listed above are compared to the transport data listed in the attached table.

1.) If the calculated fluid velocity is below the incipient transport velocity of the debris type being evaluated, that debris type will not transport and may be excluded from further consideration of sump blockage. Note that both the debris material and the debris geometry (size) determine the debris type.

2.) If the calculated fluid velocity is not sufficiently large enough to transport the debris type, compare the transport time to the settling velocity of the debris type and its distance from the sump to assess if it will settle prior to reaching the sump screen. Note that, typically, a linear velocity equal to about 7 times the settling velocity of the largest particle in the slurry of debris is required to maintain the particles in suspension (Reference 1).

3.) If the debris type settles, check if the local fluid velocity is sufficient to transport the debris type to the sump by tumbling or sliding along the containment floor.

4.) Consider if curbs and screens in the flow path to the sump.

4.1) Curbs provide an obstacle to debris types that would slide or tumble to the sump screen on the floor of the containment. For the debris type to continue to be transported to the sump, the local fluid velocity at the curb must be sufficiently large enough to lift the debris type over the curb.

4.2) Screens in the flow path can capture both suspended debris types and debris types tumbling or sliding along the containment floor.

4.3) The volume of debris type captured by either curbs or screens in the flow path is not considered for sump screen blockage.

Velocity_Calculation_Guide_R1.doc 2

DRAFT June 21, 2003 4.4) However, the debris loading on intermediate screens in the flow path must be evaluated to determine if the resulting blockage may divert or hold up flow from the sump.

4.4.1) This is accomplished by first evaluating the amount of the various types of debris that might be collected by the intermediate screen.

4.4.2) The pressure drop across the intermediate screen is then calculated using the same method as applied to the sump screen.

5.) Debris types are to be considered in the debris loading on the sump screen if:

5.1) If the calculated fluid velocity is sufficiently large to transport the debris type to the sump without the debris type settling and the debris type can pass through intermediate screens in the flow path, or, 5.2) The calculated fluid velocity is sufficiently large to lift a debris type that is calculated to slide or tumble along the floor over a curb that is in the flow path.

References:

1. Durand and Condolinos, "Hydraulic Transport of Coal and Other Solid Materials in Pipes," (1952)

Velocity_Calculation_Guide_R1.doc 3

DRAFT June 21, 2003 Debris Transport Reference Table Material Category / Type Incipient Bulk Lift-Over-Curb Terminal Comment Reference Document Transport Transport Velocity (ft/sec) Settling Velocity (ft/sec) Velocity Velocity (ft/sec) (ft/sec)

A. Fibrous Insulation

1. Fiberglass - Generic Same as Same as Same as Same as Since no data for generic fiberglass is NUKON NUKON NUKON NUKON available, it is recommended that the data for NUKON be used to represent low -density fiberglass.
2. Fiberglass - NUKON 0.06 0.09 0.22 (2-in. curb) 0.41 (6-in.)
  • Size not specified for transport NUREG/CR-6772 0.28 (6-in. curb) 0.40 (4-in.) velocity tests. The NUKON Microscopic Density = 175 lb/ft3 0.15 (2-in.) manufacturer created debris by using Macroscopic Density = 2.4 lb/ft3 air jets.
  • NUREG/CR-6224 indicates that individual fibers and small groups of fibers settle at speeds less than 0.06 ft/sec
3. Fiberglass - Temp-Mat No data specifically for Temp-Mat.

See comment. See comment. See comment. See comment. Conservatively use data for NUKON Macroscopic Density = 11.3 lb/ft3 (has a lighter macroscopic density).

4. Fiberglass - Transco (Thermal Wrap)
a. Shredded a. 0.07 a. 0.11 a. 0.22 (2-in. curb) a. 0.13
b. 4-in. x 6-in. pieces b. 0.12 b. 0.16 b. 0.25 (6-in. curb) b. Not Tested taken from NUREG/CR-6772. b. NUREG/CR-6772
c. Various Sizes - Transco c. Not Identified c. 0.12-0.4 c. Not identified c. 0.09 - 0.51
  • Transco tested various sizes of c. Transco Tests (15° C, (91° C, size debris for transport velocities. documents: ITR-size + type dependent)
  • Submersion of floating samples92-03N, dependent occurs within seconds for high ITR-93-02N

) temperatures (~90° C).

  • Settling velocity weakly dependent on temperature (higher velocities for higher temps)
5. Mineral Wool
a. 4-in. x 4-in. x 1-in. a. 0.4 a. 1.4 a. See second a. See
b. Shreds b. 0.3 b. See comment second sink.

second b. See second comment

  • No data specif ically for Temp-Mat.

comment comment b. See Conservatively use data for NUKON.

second comment

6. Miscellaneous Fibrous
a. Asbestos a. See a. See a. See comment a. See No data specifically for asbestos or
b. Unibestos comment comment b. See comment comment Unibestos. Conservatively use data for
b. See b. See b. See NUKON (has a light macroscopic comment comment comment density).

Velocity_Calculation_Guide_R0.doc 4

DRAFT June 21, 2003 Material Category / Type Incipient Bulk Lift-Over-Curb Terminal Comment Reference Document Transport Transport Velocity (ft/sec) Settling Velocity (ft/sec) Velocity Velocity (ft/sec) (ft/sec)

B. Calcium Silicate Insulation

1. Generic - Chunks with dust + 0.10 (dust + 0.35 Not tested: see Not tested: see
  • Tests performed at ~20° C. NUREG/CR-6772 fibers fibers) comment on comment on
  • Chunks were almost fully 0.25 (small dissolution dissolution dissolved after immersion in near-chunks) boiling water for 20 min.

0.30 (larger chunks)

C. Reflective Metallic Insulation

1. Stainless Steel
a. Fragments - 0.5-in. x 0.5-in. a. 0.20 a. 0.22 a. 0.30 a. 0.37
b. Fragments in. x 2-in. b. 0.28 b. 0.30 b. 0.30 (2-in. curb) b. 0.48 from NUREG/CR-6772 were used. b. NUREG/CR-6772
c. Cassette - Half Assembly c. 1.0 c. 1.0 >1.0 (6-in. curb) c. Use values
d. Covers - Inside and Outside d. 0.7 d. 0.8 c. Use values from from (b) suspended in chugging tests d. NUREG/CR-3616
e. Fragments - Various Sizes e. Use values e. Use values (b) above above (SEA document) e. SEA 95-970-01-A:2 from (a) and from (a) and d. Use values from d. Use values (b) above (b) above (b) above from (b)
e. Use values from above (b) above e. 0.3-0.4 (size dependent)
2. Aluminum Use of Lift-over curb velocity for
a. Fragments in. x 2-in. a. 0.20 a. 0.30 a. Use value from a. 0.11 stainless steel is based on similar NUREG/CR-6772 1(b), stainless behavior for incipient transport velocity steel, above and bulk transport velocity.

F. Fire Barrier

1. 3M Interam Same as Same as Same as Same as With no data for 3M Interam available, NUKON NUKON - NUKON NUKON recommend that data for low -density fiberglass be conservatively used.
2. Fiberglass blanket Same as Same as Same as Same as Since no data for generic fiberglass is NUKON NUKON NUKON NUKON available, it is recommended that the data for NUKON be used to represent low -density fiberglass.
3. Kaowool Based on similarity of other hydraulic
a. Shredded a. 0.09 a. 0.19 a. 0.25 a. 0.21 transport characteristics, suggest using NUREG/CR-6772
b. 4-in. x 6-in. b. 0.12 b. 0.16 b. 0.25 b. Use value same settling velocity for shredded and (2-in. or 6-in. curb for from (a) cut Kaowool.

both debris types) above

4. Marinite board
a. 1-in. x 1-in. a. 0.77 a. 0.79 a. Not Tested a. 0.59 - 0.63 NUREG/CR-6772
b. 4-in. x 4-in. b. 0.77 b. >= 0.99 b. Not Tested b. 0.42 - 0.60 Three values for density:

Marinite-23 = 23 lb/ft3 Marinite-36 = 36 lb/ft3 Marinite-65 = 65 lb/ft3 Velocity_Calculation_Guide_R0.doc 5

DRAFT June 21, 2003 Material Category / Type Incipient Bulk Lift-Over-Curb Terminal Comment Reference Document Transport Transport Velocity (ft/sec) Settling Velocity (ft/sec) Velocity Velocity (ft/sec) (ft/sec)

5. Silicone foam -- -- -- -- Floats - Readily transports at any NUREG/CR-6772 velocity G. Other
1. Koolphen (closed cell phenolic) See comment. See comment. See comment. See comment. Suggest using data for NUKON.
2. Min-K (microporous) See comment. See comment. See comment. See comment. Suggest using data for NUKON.
3. Lead Wool See comment. See comment. See comment. See comment.
  • Lead would settle and not transport.
  • Suggest using data for NUKON for Macroscopic Density = 10-15 lb/ft3 fabric cover.
  • Confirm site use of lead wool blankets. (May not be used.)
4. Dust / Dirt See comment. See comment. See comment. See comment. Although the density is large, sugges t using data for calcium silicate.

3 Density = 156 lb/ft

5. Sludge (Iron) N/A N/A N/A N/A No credible source of iron sludge identified for PWR's.

3 Density = 324 lb/ft H. Coatings

1. Epoxy - Generic 0.40 0.45 0.55 (2-in. curb) 0.15
  • 0.55 ft/sec results in some transport NUREG/CR-6772 over debris curb Density = 90 lb/ft3 (Nominal)
  • Tests conducted in ambient temperature water
2. Alkyd - Generic See comment. See comment. See comment. See comment. Conservatively use data for epoxy coatings (has a lighter nominal density).

Density = 94 lb/ft3 (Nominal)

3. Inorganic Zinc - Generic See comment. See comment. See comment. See comment. Conservatively use data for epoxy coatings (has a lighter nominal density).

Density = 156 lb/ft (intact)

= 437 lb/ft3 (detached, Carboline)

= 350 lb/ft3 (detached, CRC)

Velocity_Calculation_Guide_R0.doc 6

Retrieved from "https://kanterella.com/w/index.php?title=ML032030535&oldid=2199774"