NUREG-0800

(Formerly NUREG-75/087)

U.S. NUCLEAR REGULATORY COMMISSION

STANDARD REVIEW PLAN

OFFICE OF NUCLEAR REACTOR REGULATION

Rev. 3 - December 2005

USNRC STANDARD REVIEW PLAN

Standard review plans are prepared for the guidance of the Office of Nuclear Reactor Regulation staff responsible for the review of applications to construct and operate nuclear power plants. These documents are made available to the public as part of the Commission’s policy to inform the nuclear industry and the general public of regulatory procedures and policies. Standard review plans are not substitutes for regulatory guides or the Commission’s regulations and compliance with them is not required. The standard review plan sections are keyed to the Standard Format and Content of Safety Analysis Reports for Nuclear Power Plants. Not all sections of the Standard Format have a corresponding review plan.

Published standard review plans will be revised periodically, as appropriate, to accommodate comments and to reflect new information and experience.

Comments and suggestions for improvement will be considered and should be sent to the U.S. Nuclear Regulatory Commission, Office of Nuclear Reactor Regulation, Washington, D.C. 20555.

6.5.2 CONTAINMENT SPRAY AS A FISSION PRODUCT CLEANUP SYSTEM

REVIEW RESPONSIBILITIES

Primary - Organization responsible for review of chemical engineering issues. |

Secondary - Organization responsible for review of containment systems. |

I. AREAS OF REVIEW

The containment spray and the spray additive or pH control systems are reviewed to determine

the fission product removal effectiveness whenever the applicant claims a containment

atmosphere fission product cleanup function for the systems. The following areas of the

applicant’s safety analysis report (SAR) relating to the fission product removal and control

function of the containment spray system are reviewed.

1. Fission Product Removal Requirement for Containment Spray

Sections of the SAR related to accident analyses, dose calculations, and fission product

removal and control are reviewed to establish whether the applicant claims fission product

scrubbing of the containment atmosphere for the mitigation of radiological consequences

following a postulated accident. This review usually covers sections in SAR Chapters 6

and 15. 

2. Design Bases

The design bases for the fission product removal function of the containment spray system

are reviewed to verify that they are consistent with the assumptions made in the accident

evaluations in SAR Chapter 15.
Rev. 3 - December 2005 6.5.2-2

3. System Design

The information on the design of the spray system, including any subsystems and

supporting systems, is reviewed to familiarize the reviewer with the design and operation of

the system. The information includes:

a. The description of the basic design concept; the systems, subsystems, and support

systems required to carry out the fission product scrubbing function of the system; and

the components and instrumentation employed in these systems.

b. The process and instrumentation diagrams.

c. Layout drawings (plans, elevations, isometrics) of the spray distribution headers.

d. Plan views and elevations of the containment building layout.

4. Testing and Inspections

The system description is reviewed to establish the details of the preoperational test to be

performed for system verification and the postoperational tests and inspections to be

performed for verification of the continued readiness of the spray system.

5. Technical Specifications

At the operating license stage, the applicant’s proposed technical specifications are

reviewed to establish permissible outage times and surveillance requirements. 

| 6. Inspection, Test, Analysis, and Acceptance Criteria (ITAAC) 

|

| For design certification and combined license reviews, the applicant’s proposed information

| on the ITAAC associated with the systems, structures, and components (SSCs) related to

| this SRP section is reviewed in accordance with SRP Section 14.3. It is recognized that

| the review of ITAAC is performed after review of the application against acceptance criteria

| contained in this SRP section. Furthermore, the ITAAC are reviewed to assure that all

| SSCs in this area of review are identified and addressed as appropriate in accordance with

| SRP 14.3.

Review Interfaces: 

The primary reviewer also reviews any chemical additive storage requirements, materials

compatibility of the long-term containment sump and recirculation spray solutions, and organic

material decomposition including formation of organic iodides as part of SRP Sections 6.1.1 and

6.1.2.

In addition, the primary reviewer will coordinate other branches’ evaluations that interface with

the overall review of the system as follows:

| - the heat removal and automatic initiation of the containment spray system and containment

sump design (as part of SRP Section 6.2.2), 
6.5.2-3 Rev. 3 - December 2005

- the hydrogen mixing function of the containment spray system (as part of SRP

Section 6.2.5), and

- the general guidance on the initial plant test program (as part of SRP Section 14.2). |

The acceptance criteria and review procedures are given in the referenced SRP sections for the

areas of review identified above.

II. ACCEPTANCE CRITERIA

The acceptance criteria for the fission product cleanup function of the containment spray system

are based on meeting the relevant requirements of the following regulations: 

A. General Design Criterion (GDC) 41 as it relates to containment atmosphere cleanup

systems designed to control fission product releases to the reactor containment following

postulated accidents.

B. GDC 42 as it relates to containment atmosphere cleanup systems designed to permit

appropriate periodic inspections.

C. GDC 43 as it relates to containment atmosphere cleanup systems designed for appropriate

periodic functional testing.

D. 10 CFR 52.47(a)(1)(vi) provides the requirement for ITAAC for design certification reviews. |

|

E. 10 CFR 52.97(b)(1) provides the requirement for ITAAC for combined license reviews. |

The specific criteria necessary to meet the relevant requirements of GDC 41, 42, and 43

include:

1. Design Requirements for Fission Product Removal

The containment spray system should be designed in accordance with the requirements of

ANSI/ANS 56.5 (Reference 14), except that the requirements for any spray additive or |

other pH control system in this reference need not be followed.

a. System Operation

The containment spray system should be designed to be initiated automatically by an

appropriate accident signal and transferred automatically from the injection mode to the

recirculation mode to ensure continuous operation until the design objectives of the

system have been achieved. In all cases, the operating period should not be less than

2 hours. Additives to the spray solution may be initiated manually or automatically or

stored in the containment sump to be dissolved during the spray injection period.
Rev. 3 - December 2005 6.5.2-4

b. Coverage of Containment Building Volume

To ensure full spray coverage of the containment building volume, the following should

be observed:

(1) The spray nozzles should be located as high in the containment building as

practicable to maximize the spray drop fall distance.

(2) The layout of the spray nozzles and distribution headers should be such that the

cross-sectional area of the containment building covered by the spray is as large

as practicable and the spray produced is a nearly homogeneous distribution in the

containment building space. Unsprayed regions in the upper containment building

and, in particular, an unsprayed annulus adjacent to the containment building liner

should be avoided wherever possible. 

(3) In designing the layout of the spray nozzle positions and orientations, the effects of

the postaccident atmosphere should be considered, including the effects of

postaccident conditions that result in the maximum possible density of the

containment atmosphere.

c. Promotion of Containment Building Atmosphere Mixing

Because the effectiveness of the containment spray system depends on a well-mixed

containment atmosphere, consideration should be given to all design features

enhancing postaccident mixing. 

d. Spray Nozzles

The nozzles used in the containment spray system should be designed to minimize the

possibility of clogging while producing drop sizes effective for iodine absorption. The

nozzles should not have internal moving parts such as swirl vanes and turbulence

promoters. They should not have orifices or internal restrictions which narrow the flow

passage to less than 0.64 cm (0.25 inch) in diameter.

e. Spray Solution

| The partition of iodine between liquid and gas phases and retention of iodine in the

| liquid is enhanced by the alkalinity of the solution. The spray system should be

designed so that the spray solution is within material compatibility constraints. Iodinescrubbing credit is given for spray solutions whose chemistry, including any additives,

has been demonstrated to be effective for iodine absorption and retention under

postaccident conditions.

 f. Containment Sump Solution Mixing

The containment sump should be designed to permit mixing of emergency core cooling

system (ECCS) and spray solutions. Drains to the engineered safety features sump

should be provided for all regions of the containment which would collect a significant

quantity of the spray solution. Alternatively, allowance should be made for “dead”
6.5.2-5 Rev. 3 - December 2005

volumes in the determination of the pH of the sump solution and the quantities of

additives injected.

g. Containment Sump and Recirculation Spray Solutions

The pH of the aqueous solution collected in the containment sump after completion of

injection of containment spray and ECCS water and all additives for reactivity control,

fission product removal, or other purposes should be maintained at a level sufficiently

high to provide assurance that significant long-term iodine reevolution does not occur. 

The expected long-term partition coefficient is used to calculate the long-term iodine

retention. Long-term iodine retention may be assumed only when the equilibrium sump

solution pH, after mixing and dilution with the primary coolant and ECCS injection, is

above 7 (Reference 17). This pH value should be achieved by the onset of the spray

recirculation mode. 

h. Storage of Additives

The design should provide facilities for the long-term storage of any spray additives. 

These facilities should be designed so that the additives required to achieve the design

objectives of the system are stored in a state of continuous readiness whenever the

reactor is critical for the design life of the plant. The storage facilities should be

designed to prevent freezing, precipitation, chemical reaction, and decomposition of the

additives. For sodium hydroxide storage tanks, heat tracing of tanks and piping is

required whenever exposure to temperatures below 4.5 °C (40 °F) is predicted. An

inert cover gas should be provided for solutions that may deteriorate when exposed to

air. 

i. Single Failure

The system should be able to function effectively and meet all the criteria in

Subsection II with a single failure of an active component in the spray system, in any of

its subsystems, or in any of its support systems.

2. Testing

Tests should be performed to demonstrate that the containment spray system, as installed,

meets all design requirements for an effective fission-product-scrubbing function. Such

tests should include preoperational verification of:

a. freedom of the containment spray piping and nozzles from obstructions,

b. the capability of the system to deliver the required spray flow, and 

c. the capability of the system to deliver spray additives (if any are needed) and to achieve

the sump solution pH specified in the SAR. For a system such as a gravity feed

system, whose performance is sensitive to the as-built piping layout, the testing should

be performed at full flow. 
Rev. 3 - December 2005 6.5.2-6

3. Technical Specifications

The technical specifications should specify appropriate limiting conditions for operation,

tests, and inspections to provide assurance that the system is capable of performing its

design function whenever the reactor is critical. These specifications should include:

a. The operability requirements for the system, including all active and passive devices, as

a limiting condition for operation (with acceptable outage times). The following items

should be specifically included: containment spray pumps, additive pumps (if any),

additive mixing devices (if any), valves and nozzles, additive quantity and concentration

in additive storage tanks, and nitrogen (or other inert gas) pressure in additive storage

tanks. 

b. Requirements for periodic inspection and sampling of the contents of additive storage

tanks to confirm that the additive quantity and concentrations are within the limits

established by the system design.

c. Requirements for periodic testing and exercising of the active components of the

system and verification that essential piping and passive devices are free of

obstructions.

Acceptable methods for computing fission product removal rates by the spray system are given

in Subsection III.4.c, “Fission Product Cleanup Models.” 

Although credit is granted for containment spray removal of fission products in the calculations

of accident doses, the acceptance criteria of containment leakage in SRP Section 6.2.1.1.A and

the acceptance criteria of the engineered safety feature atmosphere cleanup systems in SRP

Section 6.5.1 should still be met. 

| Technical Rationale:

|

| The technical rationale for application of the above acceptance criteria to the containment spray

| system is discussed as follows.

|

| A. GDC 41 establishes the design requirements for containment atmosphere cleanup systems

| which function to reduce the concentration and quality of fission products released to the

| environment following postulated accidents. The radiological consequences of accidents in

| Chapter 15 of the SAR depend on the quantity and quality of the fission products released

| from containment. The containment spray system may be relied upon to provide an

| effective means for removal of iodine and other fission products released to the

| containment atmosphere following a design-basis accident. Fission product iodine is

| removed and retained by the spray solution and is unavailable for release to the

| environment. Compliance with GDC 41 ensures that the containment spray system will

| accomplish the fission product removal function assumed in the Chapter 15 radiological

| consequence calculations.

|

| B. GDC 42 establishes the requirements for the inspection of containment atmosphere

| cleanup systems. The inspection of important components such as pumps, valves, tanks,

| and flow paths ensures the integrity and capability of the system. The containment spray
6.5.2-7 Rev. 3 - December 2005

system may be credited with providing fission product removal and retention following |

design-basis accidents. Proper operation of the containment spray system depends on the |

integrity of system pumps, valves, spray nozzles, chemical additive systems, and flow |

paths. Periodic inspection ensures that these components are capable of performing their |

design function in the event of an accident. |

|

C. GDC 43 establishes the requirement that the design of the containment atmosphere |

cleanup systems allow appropriate periodic functional testing. The capability of the |

containment spray system to perform the function of fission product removal depends on |

the operability of the pumps, valves, nozzles, chemical additive systems, actuation circuitry, |

and power supplies for the system. The periodic functional testing of the containment |

spray system and its components provides assurance of system operability and the |

capability to fulfill the design function of fission product removal in the event of a design- |

basis accident. |

III. REVIEW PROCEDURES

The reviewer selects and emphasizes aspects covered by this SRP section as appropriate for a

particular plant. The judgment of which areas need to be given attention and emphasis in the

review is based on whether the material presented is similar to material recently reviewed for

other plants and whether items of special safety significance are involved.

The reviewer determines whether the containment spray system is used for fission product

removal purposes. SAR Chapter 15 should be reviewed to establish whether the accident dose

evaluations assume a fission product removal function for the containment spray system. If the

containment spray system is not used for mitigating radiological dose, no further review is

required under this SRP section. If the containment spray system is used for mitigation of

radiological doses, then the review of the fission product removal function of the containment

spray system follows the procedure and carries out the review responsibilities outlined below.

1. System Design

Review of the system design includes an examination of the components and design

features necessary to carry out the fission product scrubbing function, including: 

a. Spray Solution Chemistry (primary reviewer)

The reviewer identifies the forms of iodine for which spray removal credit is claimed in

the accident analyses (SAR Chapter 15). Containment spray systems may be

designed for removal of iodine in the elemental form, in the form of organic compounds,

and in the particulate form. The reviewer also determines whether spray removal credit

is claimed for other particulate fission products.

The systems or subsystems required to carry out the fission-product-scrubbing function

of the containment spray are identified, for example, the spray system, recirculation

system, spray additive system, and borated water source. The design of the systems

involved is reviewed in order to:
Rev. 3 - December 2005 6.5.2-8

(1) Ascertain the effectiveness of any chemical additive for iodine removal and

retention. 

(2) Ascertain that the amount of additive is sufficient to meet the acceptance criteria of

Subsection II or that adequate justification is given for the iodine removal and

retention effectiveness for the range of concentrations encountered. The

concentrations in the storage facility, the chemical addition lines, the spray solution

injection, the containment sump solution, and the recirculation spray solution

should be examined. The extremes of the additive concentrations should be

determined with the most adverse combination of ECCS, spray, and additive

pumps (if any) assumed to be operating and considering a single failure of active

components in the systems or subsystems. 

The reviewer verifies that the stability of the containment spray and sump solutions and

the corrosion, solidification, and precipitation behavior of the chemical additives have

appropriately been considered for the range of concentrations encountered.

b. System Operation (secondary reviewer)

The time and method of system initiation, including chemical addition, is reviewed to

confirm that the acceptance criteria of Subsection II are met. Automatic initiation of

spray is reviewed under SRP Section 6.2.2. The system should operate continuously

until the fission product removal objectives of the system are met. The reviewer should

confirm that all requirements listed in the acceptance criteria, particularly the

requirements for spray coverage and sump solution pH, are met during the recirculation

phase. Switchover from the injection mode to the recirculation mode following initiation

to the spray system operation must be automatic to prevent damage to the spray

pumps through loss of suction. 

c. Spray Distribution and Containment Mixing (secondary reviewer)

The number and layout of the spray headers used to distribute the spray flow in the

containment space are reviewed. The reviewer verifies that the layout of the headers

ensures that the spray covers essentially the entire horizontal cross section of the

containment building under minimum spray flow conditions. The effect of the

postaccident high-temperature and pressure conditions in the containment atmosphere

on the spray droplet trajectories should be accounted for in determining the area

covered by the spray.

The layout of the containment building is reviewed to determine if any areas of the

containment free space are not sprayed. The mixing rate attributed to natural

convection between the sprayed and unsprayed regions of the containment building is

assumed to be two turnovers of the unsprayed region(s) per hour, provided that

adequate flow exists between these regions. The applicant would have to justify other

rates. The containment building atmosphere may be considered a single well-mixed

space if the spray covers at least 90 percent of the containment building space and if a

ventilation system is available for adequate mixing of any unsprayed compartments. 
6.5.2-9 Rev. 3 - December 2005

d. Spray Nozzles (secondary reviewer)

The design of the spray nozzles is reviewed to confirm that the spray nozzles are not

subject to clogging from debris entering the recirculation system through the

containment sump screens. 

e. Containment Sump Mixing (primary reviewer)

The mixing of the spray water containing any chemical additive and water without

additive (such as spilling ECCS coolant) in the containment sump is reviewed. The

reviewer considers areas of the containment building that are exposed to the spray but

are without direct drains to the recirculation sump (such as the refueling cavity). The

reviewer confirms that the required sump solution concentrations are achieved within

the appropriate time intervals. The pH of the sump solution should be reviewed in

regard to iodine reevolution, using the criteria given in Subsection II.1.g and the

procedure in Subsection III.4.c.(2). 

f. Storage of Additives (primary reviewer)

The design of any additive storage tank is reviewed to establish whether heat tracing is

required to prevent freezing or precipitation in the tank. The reviewer determines

whether an inert cover gas is provided for the tank to prevent reactions of the additive

with air such as the formation of sodium carbonate by the reaction of sodium hydroxide

and carbon dioxide. Alternatively, the reviewer verifies by a conservative analysis that

an inert cover gas is not required. 

g. Single Failure (primary reviewer/secondary reviewer)

The system schematics are reviewed by inspection, postulating single failures of any

active component in the system, including inadvertent operation of valves that are not

locked open. The review is performed with respect to the fission product removal

function, considering conditions that could result in fast as well as slow injection of the

spray solution.

2. Testing (secondary reviewer)

At the construction permit stage, the containment spray concept and the proposed tests of

the system are reviewed to confirm the feasibility of verifying the design functions by

appropriate testing. At the operating license stage, the proposed tests of the system and

its components are reviewed to verify that the tests will demonstrate that the system, as

installed, is capable of performing—within the bounds established in the description and

evaluation of the system—all functions essential for effective fission product removal

following postulated accidents. 

3. Technical Specifications (primary reviewer/secondary reviewer)

The technical specifications are reviewed to verify that the system, as designed, is capable

of meeting the design requirements and that it remains in a state of readiness whenever

the reactor is critical.
Rev. 3 - December 2005 6.5.2-10

a. Limiting Conditions for Operation

The limiting conditions for operation should require the operability of the containment

spray pumps, all associated valves and piping, the appropriate quantity of additives,

and any metering pumps or mixing devices.

b. Tests

Preoperational testing of the system, including the additive storage tanks, pumps (if

any), piping, and valves, is required. In particular, the preoperational testing should

verify that the system, as installed, is capable of delivering a well-mixed solution

containing all additives in concentrations that are within the design margins assumed in

the dose analyses of SAR Chapter 15. 

Periodic testing and exercising of all active components should include the spray

pumps, metering pumps (if any), and valves. Confirmation should be made periodically

that passive components, such as all essential spray and spray additive piping, and any

passive mixing devices are free of obstructions. The contents of the spray additive

storage tanks should be sampled and analyzed periodically to verify that the

concentrations are within the established limits, that no concentration gradients exist,

and that no precipitates have formed. 

| 4. Fission Product Removal Effectiveness (primary reviewer)

The fission product removal effectiveness of the system is calculated to establish the

degree of dose mitigation by the containment spray system following the postulated

accident. The mathematical model used for this calculation should reflect the preceding

steps of the review. The analysis and assumptions are as follows:

a. The amounts of fission products assumed to be released to the containment space are

obtained from Regulatory Guide 1.3 (Reference 4), Regulatory Guide 1.4

| (Reference 5), or Regulatory Guide 1.183 (Reference 6) as appropriate. The amounts

of airborne fission product inside the containment building depend on plateout on

interior surfaces, removal by the spray system and other engineered safety features

present, radioactive decay, and outleakage from the containment building.

| If the value in Position C.1.a of Regulatory Guides 1.3 (Reference 4) and 1.4

| (Reference 5) is used in the calculation of fission product removal, then deposition by

| plateout, as described in paragraph III.4.c of this SRP section, should not be

| considered as an additional removal mechanism. Deposition by plateout is already

| accounted for in the regulatory guide values.

b. The removal of fission products from the containment atmosphere by the spray is

considered a first-order removal process. The removal coefficient 8 (lambda) for each

of the sprayed regions of the containment is computed. Removal coefficients for

time-dependent wall plateout are also calculated. The coefficients for spray removal

and wall plateout are summed. The removal lambdas are the input parameters of a

computer model for dose calculation. 
6.5.2-11 Rev. 3 - December 2005

c. Fission Product Cleanup Models

Based on the information in the SAR, the reviewer estimates how large an area of the

interior surfaces of the containment building could be washed by the spray system, the

volume flow rate of the system (assuming a single failure), the average spray drop fall

height and the mass-mean diameter of the spray drops. The effectiveness of a

containment spray system may be estimated by considering the chemical and physical

processes that can occur during an accident during which the system operates. Models

that consider such process are reviewed on a case-by-case basis.

In the absence of detailed models, reviewers should use the following simplifications. 

Experimental results (References 16, 18, and 15) and computer simulations of the

chemical kinetics (Reference 10) show that an important factor in determining the

effectiveness of sprays against elemental iodine vapor is the concentration of iodine in

the spray solution. Experiments with fresh sprays with no dissolved iodine were found

to be quite effective at scrubbing elemental iodine at a pH as low as 5 (References 18

and 15). Solutions with dissolved iodine such as the sump solutions that recirculate

after an accident may revolatilize iodine if the solutions are acidic (References 17 and

10). Chemical additives in the spray solution have no significant effect on aerosol

particle removal because this removal process is largely mechanical.

(1) Elemental iodine removal during spraying of fresh solution

During injection, the removal of elemental iodine by wall deposition can be

estimated by the equation

Where, 8w is the first-order removal coefficient by wall deposition, A is the wettedsurface area, V is the containment building net free volume, and Kw is a masstransfer coefficient. All available experimental data are conservatively bounded if

Kw is taken to be 4.9 meters per hour (Reference 7, page 17). 

During injection, the effectiveness of the spray against elemental iodine vapor is

chiefly determined by the rate at which fresh-solution surface area is introduced

into the containment building atmosphere. The rate of solution surface created per

unit gas volume in the containment atmosphere can be estimated as 6F/VD, where

F is the volume flow rate of the spray pump, V is the containment building net free

volume, and D is the mass-mean diameter of the spray drops. The first-order

removal coefficient by spray, 8s, may be taken to be 

where Kg is the gas-phase mass-transfer coefficient and T is the time of fall of the

drops, which may be estimated by the ratio of the average fall height to the
Rev. 3 - December 2005 6.5.2-12

terminal velocity of the mass-mean drop (Reference 20). This equation represents

a first-order approximation if a well-mixed droplet model is used for the spray

efficiency. The equation is valid for 8s values equal to or greater than 10 per hour. 

8s must be limited to 20 per hour to prevent extrapolation beyond the existing data

for boric acid solutions with a pH of 5 (References 16 and 15). For 8s values less

than 10 per hour, analyses using a more sophisticated expression are

recommended. 

(2) Elemental iodine removal during recirculation of sump solution

The sump solution at the end of injection is assumed to contain fission products

washed from the reactor core and removed from the containment atmosphere. If

the solution is acidic, the radiation absorbed by the sump solution generates

enough hydrogen peroxide (Reference 19) to react with both iodide and iodate ions

and make elemental iodine reevolution possible (Reference 17). For sump

solutions having pH values less than 7, molecular iodine vapor should be

conservatively assumed to evolve into the containment atmosphere

(Reference 12).

Information on the partition coefficients for molecular iodine is given in

References 12, 9, and 8. The equilibrium partitioning of iodine between the sump

liquid and the containment atmosphere is examined for the extreme additive

concentrations reviewed in Section III.1.a.(2), combined with the range of possible

temperatures in the containment atmosphere and the sump solution. The reviewer

should consider all known sources and sinks of acids and bases in a postaccident

containment environment (e.g., alkaline earth and alkali metal oxides, nitric acid

generated by radiolysis of nitrogen and water, alkaline salts or lye additives). The

minimum iodine partition coefficient determined for these conditions forms the

basis of the ultimate iodine decontamination factor in the staff’s analysis (described

in Subsection III.4.d). 

(3) Organic iodides

It is conservative to assume that organic iodides are not removed by either spray

or wall deposition. Radiolytic destruction of iodomethane may be modeled, but the

model must also consider radiolytic production (Reference 11). Engineered safety

features designed to remove organic iodides are reviewed on a case-by-case

basis. 
6.5.2-13 Rev. 3 - December 2005

(4) Particulates

The first-order removal coefficient for particulates, 8p, can be determined by the

method described in Reference 13, or estimated by: 

where h is the spray drop fall height, V is the containment building net free volume,

F is the spray flow, and E/D is the ratio of a dimensionless collection efficiency E to

the average spray drop diameter D. Since the removal of particulate material

chiefly depends on the relative sizes of the particles and the spray drops, it is

convenient to combine parameters that cannot be known (Reference 7). It is

conservative to assume E/D to be 10 per meter initially (i.e., 1% efficiency for spray

drops of 1 millimeter in diameter), changing abruptly to 1 spray drop per meter after

the aerosol mass has been depleted by a factor of 50 (i.e., 98% of the suspended

mass is 10 times more readily removed than the remaining 2%).

d. The iodine decontamination factor, DF, is defined as the maximum iodine concentration

in the containment atmosphere divided by the concentration of iodine in the

containment atmosphere at some time after decontamination. The DF for the

containment atmosphere achieved by the containment spray system is determined by

the following equation (Reference 14): 

where H is the effective iodine partition coefficient, Vs is the volume of liquid in

containment sump and sump overflow, and Vc is the containment building net free

volume less Vs.

The effectiveness of the spray in removing elemental iodine is presumed to end when

the maximum elemental iodine DF is reached. This value cannot exceed 200. 

Because the removal mechanisms for organic iodides and particulate iodines are

significantly different from and slower than the mechanisms for elemental iodine, there

is no need to limit the DF for organic iodides and particulate iodines.

For reviews under 10 CFR Part 52, the reviewer should follow the above procedures to verify |

that the design set forth in the safety analysis report, and as applicable, site interface |

requirements, and combined license action items, meet the acceptance criteria. Following this |

review, SRP Section 14.3 should be followed for the review of Tier I information for the design, |

including the site parameters, interface criteria, and ITAAC. |
Rev. 3 - December 2005 6.5.2-14

IV. EVALUATION FINDINGS

The reviewer verifies that the applicant has provided sufficient information and that the review

and calculations support conclusions of the following type to be included in the staff’s safety

evaluation report. The reviewer also states the bases for those conclusions.

The concept on which the proposed system is based has been demonstrated to be

effective for fission product removal and retention under postaccident conditions. The

proposed system design is an acceptable application of this concept. The system provides

suitable redundancy in components and features so that its safety function can be

accomplished assuming a single failure.

The proposed preoperational tests, postoperational testing and surveillance, and proposed

limiting conditions for operation of the spray system provide adequate assurance that the

fission product scrubbing function of the containment spray system will meet or exceed the

effectiveness assumed in the accident evaluation. 

The staff concludes that the containment spray system is acceptable as a fission product

cleanup system and meets the requirements of GDC 41 with respect to the iodine removal

function following a postulated loss-of-coolant accident, GDC 42 with respect to the

periodic inspection of the system, and GDC 43 with respect to the periodic testing of the

system.

| For design certification and combined license reviews, the findings will also summarize (to the

| extent that the review is not discussed in other safety evaluation report sections) the staff’s

| evaluation of the ITAAC, and as applicable, design acceptance criteria (DAC), interface

| requirements, and combined license action items relevant to this SRP section.

V. IMPLEMENTATION

The following guidance is for applicants and licensees concerning the staff’s plans for using this

SRP section.

| The staff will use this SRP section in performing safety evaluations of design certifications and

| license applications submitted by applicants pursuant to 10 CFR Parts 50 or 52. Except when

the applicant proposes an acceptable alternative method for complying with specified portions

of the Commission’s regulations, the staff will use the method described herein to evaluate

conformance with Commission regulations.

|

| The provisions of this SRP section apply to reviews of applications docketed 6 months or more

| after the date of issuance of this SRP section.

VI. REFERENCES

1. 10 CFR Part 50, Appendix A, General Design Criterion 41, “Containment Atmosphere

Cleanup.”

2. 10 CFR Part 50, Appendix A, General Design Criterion 42, “Inspection of Containment

Atmosphere Cleanup Systems.”
6.5.2-15 Rev. 3 - December 2005

3. 10 CFR Part 50, Appendix A, General Design Criterion 43, “Testing of Containment

Atmosphere Cleanup Systems.”

4. U.S. Nuclear Regulatory Commission, Regulatory Guide 1.3, “Assumptions Used for

Evaluating the Potential Radiological Consequences of a Loss-of-Coolant Accident for

Boiling Water Reactors.”

5. U.S. Nuclear Regulatory Commission, Regulatory Guide 1.4, “Assumptions Used for

Evaluating the Potential Radiological Consequences of a Loss-of-Coolant Accident for

Pressurized Water Reactors.”

6. U.S. Nuclear Regulatory Commission, Regulatory Guide 1.183, “Alternate Radiological |

Source Terms for Design Basis Accidents at Nuclear Power Reactors.” |

7. A.K. Postma, R.R. Sherry, and P.S. Tam, “Technological Bases for Models of Spray

Washout of Airborne Contaminants in Containment Vessel,” NUREG/CR-0009,

October 1978. 

8. J.T. Bell, D.O. Campbell, M.H. Lietzke, D.A. Palmer, and L.M. Toth, “Aqueous Iodine

Chemistry in LWR Accidents: Review and Assessment,” NUREG/CR-2493, April 1982. 

9. J.T. Bell, M.H. Lietzke, and D.A. Palmer, “Predicted Rates of Formation of Iodine

Hydrolysis Species at pH Levels, Concentrations, and Temperatures Anticipated in LWR

Accidents,” NUREG/CR-2900, October 1982. 

10. M.F. Albert, “The Absorption of Gaseous Iodine by Water Droplets,” NUREG/CR-4081, July

1985. 

11. E.C. Beahm, W.E. Shockley, and O.L. Culberson, “Organic Iodide Formation Following

Nuclear Reactor Accidents,” NUREG/CR-4327, December 1985.

12. E.C. Beahm, W.E. Shockley, C.F. Weber, S.J. Wisbey, and Y-M. Wang, “Chemistry and

Transport of Iodine in Containment,” NUREG/CR-4697, October 1986. 

13. D.A. Powers, S.B. Burson, “A Simplified Model of Aerosol Removal by Containment |

Sprays,” NUREG/CR-5966, June 1993. |

14. ANSI/ANS 56.5-1979 (reaffirmed 1987), “PWR and BWR Containment Spray System |

Design Criteria,” American National Standards Institute.

15. A.K. Postma, L.F. Coleman, and R.K. Hilliard, “Iodine Removal from Containment

Atmospheres by Boric Acid Spray,” Pacific Northwest Laboratories report, BNP-100, July

1970. 

16. R.K. Hilliard, A.K. Postma, J.D. McCormack, L.F. Coleman, and C.E. Lunderman, “Removal

of Iodine and Particles From Containment Atmospheres - Containment Systems

Experiments,” Pacific Northwest Laboratories report, BNWL-1244, February 1970.
Rev. 3 - December 2005 6.5.2-16

17. C.C. Lin, “Chemical Effects of Gamma Radiation on Iodine in Aqueous Solutions,” Journal

of Inorganic and Nuclear Chemistry, 42, pp. 1101-1107.

18. S. Barsali, F. Bosalini, F. Fineschi, B. Guerrini, S. Lanza, M. Mazzini, and R. Mirandola,

“Removal of Iodine by Sprays in the PSICO 10 Model Containment Vessel,” Nuclear

Technology, 23, pps. 146-156 (August 1974).

19. A.O. Allen, “The Radiation Chemistry of Water and Aqueous Solutions,” Van Nostrand,

New York (1961). 

20. G.B. Wallis, “The Terminal Speed of Single Drops or Bubbles in an Infinite Medium,”

International Journal of Multiphase Flow, 1, pps. 491-511 (1974).

| 21. NUREG-1465, “Accident Source Terms for Light-Water Nuclear Power Plants,” June 1992.
6.5.2-17 Rev. 3 - December 2005

Appendix: Description of Changes

The following summarizes the changes in Revision 3, dated December 2005. Minor editorial

changes and formatting changes are not identified by side bars. 

1. Review Responsibilities: 

a. Editorial changes made to reflect the review responsibilities as functions. The

cognizant organization is maintained separately from the SRP. Similarly, references to

other SRP sections no longer identify the specific branch.

2. Areas of Review:

a. Added ITAAC as an area of review

b. Added “automatic initiation of spray” under SRP Section 6.2.2. as a review interface.

c. Added initial plant test program (as part of SRP 14.2) as a review interface.

d. Editorial change to revise the review interface section to identify SRP sections and

functions and not individual organizations.

3. Acceptance Criteria:

a. Added citations for ITAAC

b. Editorial change to make the citation of references consistent with the SRP-UDP

specified format.

c. Editorial change to add reference to ANSI/ANS 56.5

d. Editorial change to add clarity to “retention of iodine in the liquid”

e. Technical rationale associated with GDC 41, 42, and 43 was formulated and added to

this section in accordance with the specified SPR-UDP format. 

4. Review Procedures:

a. A new reference was added to the current Regulatory Guide 1.183, “Alternative

Radiological Source Terms for Evaluating Design Basis Accidents at Nuclear Power

Reactors.”

b. A new paragraph was added to the Review Procedures to address NRC staff concerns

regarding double counting of fission product removal by plateout when using

Regulatory Guides 1.3 or 1.4 in conjunction with the procedures in the SRP.

c. Draft NUREG-1465 was introduced in the 1996 draft SRP to specifically address the CE

System 80+ and the GE ABWR. This reference is being removed because the model,

which is now applicable to other designs, is captured in RG 1.183. Note: There was a

comment received on the 1996 draft SRP section related to this reference, specifically

on the use of “draft” NUREG and its applicability to other designs. Regulatory Guide

1.183 encompasses this reference; therefore the reference was deleted.
Rev. 3 - December 2005 6.5.2-18

d. NUREG/CR-5966 was introduced in the1996 draft SRP. This reference was in draft

SRP and it was moved to section III.4.c.(4), “Particulates” as an acceptable method for

determining first-order iodine removal coefficient, 8p.”

e. Provide administrative limit for the maximum allowable decontamination factor in the

post-LOCA containment environment. 

f. Added paragraph on implementing of 10 CFR 52. A standard paragraph was added to

address Review Procedures in design certification reviews.

5. Evaluation Findings:

Added paragraph on Applicability of 10 CFR 52 for design certification reviews.

6. Implementation: 

 Editorial changes capturing applicability to Part 52 and time-frame in which SRP 

update goes into effect.

7. References:

a. Renumbered per SRP update format.

b. Added 3 new references as described above.
BIBLIOGRAPHIC DATA SHEET

(See instructions on the reverse)

NRC FORM 335

(9-2004)

NRCMD 3.7

U.S. NUCLEAR REGULATORY COMMISSION 1. REPORT NUMBER

 (Assigned by NRC, Add Vol., Supp., Rev.,

 and Addendum Numbers, if any.)

NUREG-0800

3. DATE REPORT PUBLISHED

MONTH

December

YEAR

2005

4. FIN OR GRANT NUMBER

2. TITLE AND SUBTITLE

NUREG-0800, Chpt 6, Section 6.5.2, Rev. 3, "Containment Spray as a Fission Product Cleanup

System," to the Standard Review Plan for the Review of Safety Analysi Reports for Nuclear

Power Plants, LWR Edition

5. AUTHOR(S)

K. Parczewski, NRR/NRC

6. TYPE OF REPORT

Regulatory, Final

7. PERIOD COVERED (Inclusive Dates)

8. PERFORMING ORGANIZATION - NAME AND ADDRESS (If NRC, provide Division, Office or Region, U.S. Nuclear Regulatory Commission, and mailing address; if contractor,

Division of Component Integrity

9. SPONSORING ORGANIZATION - NAME AND ADDRESS (If NRC, type "Same as above"; if contractor, provide NRC Division, Office or Region, U.S. Nuclear Regulatory Commission, 

Division of New Reactor Licensing

provide name and mailing address.)

and mailing address.)

10. SUPPLEMENTARY NOTES

11. ABSTRACT (200 words or less)

This is a revision to the Standard Review Plan that includes guidance related to 10 CFR Part 52 applicability, general formatting

and editorial changes, and updated references.

12. KEY WORDS/DESCRIPTORS (List words or phrases that will assist researchers in locating the report.)

NRC, Standard Review Plan, NUREG-0800, Section 6.5.2, Containment Spray

14. SECURITY CLASSIFICATION

13. AVAILABILITY STATEMENT

Unlimited

(This Page)

unclassified

(This Report)

unclassified

15. NUMBER OF PAGES

16. PRICE

NRC FORM 335 (9-2004) PRINTED ON RECYCLED PAPER

Office of Nuclear Reactor Regulation

U.S. Nuclear Regulatory Commission

Washington, DC 20555-0001

Office of Nuclear Reactor Regulation

U.S. Nuclear Regulatory Commission

Washington, DC 20555-0001