ML031920647

To Ice Condenser Utility Group Topical Report No. ICUG-001: Application of the Active Ice Mass Management Concept to the Ice Condenser Ice Mass Technical Specification

ML031920647
Person / Time
Site:	Mcguire, Catawba, Watts Bar, Sequoyah, Cook, McGuire
Issue date:	06/19/2003
From:	Lytton R Duke Power Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
TAC MB3379 ICUG-001
Download: ML031920647 (188)

Text

M Duke Duke Power 1?Power Encrgy Center

-W EnUwer P.O. Box 1006 A Duke EnerCgy Charlotte, NC 28201-1006 June 19, 2003 U. S. Nuclear Regulatory Commission Washington, D. C. 20555-0001 Attention: Document Control Desk

Subject:

Revision 2 to Ice Condenser Utility Group Topical Report No. ICUG-001:

Application of the Active Ice Mass Management Concept to the Ice Condenser Ice Mass Technical Specification (TAC No. MB3379)

Please find enclosed Revision 2 to non-proprietary topical report ICUG-OOI, "Application of the Active Ice Mass Management Concept to the Ice Condenser Ice Mass Technical Specification." This revision is submitted by the Ice Condenser Utility Group (ICUG) for NRC approval. The methodologies provided in this topical report support current and future license amendment request adopting Technical Specification Traveler Form (TSTF)-429.

A draft Safety Evaluation Report (SER) for Revision 0 of this topical report dated May 6, 2003, and discussion during a May 13, 2003 ICUG/NRC meeting identified additional information needs. Revision 2 updates revision 0 of this topical report to address those needs.

A draft revision 2 this topical report was sent to NRC via letter dated 5/29/03. The only difference between the enclosed revision 2 and the draft version is the addition of a new subsection to Chapter III. This subsection provides an example calculation illustrating how the statistical methodology is utilized in assuring compliance with the proposed surveillance requirements of TSTF-429.

If there are any questions or if additional information is needed, please contact the undersigned at (704) 382-3970 or rsl3tton(dduke-energy.com.

Sincerely, R. S. Lytton Chair, Ice Condenser Utility Group Enclosure G

xc(w/enclosure): Robert E. Martin (addressee only, jcopies)

-i-a-T

Ice Condenser Utility Group Application of the Active ce Mass Management Concept to the Ice Condenser Ice Mass Technical Specification Topical Report ICUG-001, Revision 2 June 2003 NON-PROPRIETARY

_ Duke Duke Power t7Power.

Energy Cnter A D-1 -V C-"y P.O. Box 1006 Charlocw, NC 28201-1006 June 19, 2003 U. S. Nuclear Regulatory Commission Washington, D. C. 20555-0001 Attention: Document Control Desk

Subject:

Revision 2 to Ice Condenser Utility Group Topical Report No. ICUG-OOl:

Application of the Active Ice Mass Management Concept to the Ice Condenser Ice Mass Technical Specification (TAC No. MB3379)

Please find enclosed Revision 2 to non-proprietary topical report ICUG-00 1, "Application of the Active Ice Mass Management Concept to the Ice Condenser Ice Mass Technical Specification." This revision is submitted by the Ice Condenser Utility Group (ICUG) for NRC approval. The methodologies provided in this topical report support current and future license amendment request adopting Technical Specification Traveler Form (TSTF)-429.

A draft Safety Evaluation Report (SER) for Revision 0 of this topical report dated May 6, 2003, and discussion during a May 13, 2003 ICUG/NRC meeting identified additional information needs. Revision 2 updates revision 0 of this topical report to address those needs.

A draft revision 2 this topical report was sent to NRC via letter dated 5/29/03. The only difference between the enclosed revision 2 and the draft version is the addition of a new subsection to Chapter III. This subsection provides an example calculation illustrating how the statistical methodology is utilized in assuring compliance with the proposed surveillance requirements of TSTF-429.

If there are any questions or if additional information is needed, please contact the undersigned at (704) 382-3970 or rslvtton(Rduke-energ.com.

Sincerely, P. S. 49 R. S. Lytton Chair, Ice Condenser Utility Group Enclosure xc(w/enclosure): Robert E. Martin (addressee only, 10 copies)

-.- 1 The information contained in this topical report is considered non-proprietary. As the sole property of the Ice Condenser Utility Group, revision to it in whole or in part or reproduction for the purpose of general distribution is not permitted without the express written consent of ICUG.

Signatures below indicate Licensee endorsement of the technical concepts presented herein.

ce Condenser Utility Group Representatives Russ Lytton Bob Fulbright Bobby Lamb Mike Wilder Joe McKeown Charlie Kelly Duke Energy Corporation, Nuclear Engineering-Chair Duke Energy Corporation, McGuire Nuclear Station Engineering Duke Energy Corporation, McGuire Nuclear Station Maintenance Duke Energy Corporation, McGuire Nuclear Station Licensing Duke Energy Corporation, Catawba Nuclear Station Engineering Duke Energy Corporation, Catawba Nuclear Station Maintenance For Catawba I McGuire Nuclear Stations:

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4I 2 6/11/D 3 Jennifer Regan Bob Ives Jan Bajraszewski For Sequoyah Nuclea Tennessee Valley Authority, Sequoyah Nuclear Plant Engineering Tennessee Valley Authority, Sequoyah Nuclear Plant Maintenance Tennessee Valley Authority, Sequoyah Nuclear Plant Licensing Lr Plant:

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Phil Smith Tennessee Valley Authority, Watts Bar Nuclear Plant Engineering Gary Jordan Tennessee Valley Authority, Watts Bar Nuclear Plant Engineering Paul Pace Tennessee Valley Authority, Watts Bar Nuclear Plant Licensing For Watts Bar Nuclear Plant:

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Brenda Kovarik Paul Leonard American Electric Power Company, D.C. Cook Nuclear Plant Engineering American Electrc Power Company, D.C. Cook Nuclear Plant Engineerng luclear Plant:

//p For Donald C. Cook Ice Condenser Executive Steerinq Team Representatives H. B. Barron, Jr.

G. R. Peterson R. T. Purcell J. E. Maddox M. W. Rencheck Duke Energy Corp., Site Vice President, McGuire Nuclear Station-Chair Duke Energy Corp., Site Vice President, Catawba Nuclear Station Tennessee Valley Authority, Site Vice President, Sequoyah Nuclear Plant Tennessee Valley Authority, Engineering Manager, Watts Bar Nuclear Plant American Electric Power Co., Vice President-Engineering, D.C. Cook Nuclear Plant Additional assistance provided by MPR Associates, Inc.

TOPICAL REPORT ICUG-001, Revision 2 June 2003 i

Topical Report ICUG-001 Application of the Active Ice Mass Management Concept to the ce Condenser Ice Mass Technical Specification Table of Contents

> Overview 0-1 Active Ice Mass Management Industry Challenges Summary of Signfficant Aspects Applicability to Ice Condenser Plants 1: Ice Mass Recuirement Design Basis and Industry Data I-1 Purpose/Scope Design Basis Original Ice Mass Technical Specification Requirements Historical Data Historical Data Analysis AIMM Methodology Determinatfon of Ice Basket Mass in AIMM Practice The Radial Zone Concept Regions of Localized Degraded Mass Conclusions

> II: Ice Basket Mass Determination Methodology II-1 Purpose/Scope Discussion Preferred Ice Mass Determination Method Altemate Ice Mass Determination Methods Standards: Ice Basket Mass Determination Uncertainty Concepts Regarding Uncertainty Error Precision of Instrument Readings and Raw Data Quantffying Measurement Uncertainty Historical data Validity - Altemate Ice Mass Determination Methods Examples Example Summary Conclusions

> III: Ice Mass Statistical Sampling Plan III-1 Purpose/Scope ice Mass Statistical Strategy Sample Size Stratified Sampling Altemate Mass Determination Methods Altemate Basket Selection Strategy Applications of Sampling Plan Detailed Analysis: Radial Zone A Summary

> References R-1

> Apendix A A-1 TOPICAL REPORT ICUG-001, Revision 2 June 2003

Topical Report ICUG-001 Application of the Active Ice Mass Management Concept to the Ice Condenser ce Mass Technical Specification List of Figures and Tables Figures Figure 0-1. Ice Mass Surveillance Strategy 0-4 Figure 1-1. Typical Plan View of Containment Building 1-3 Figure 1-2. Row-Group Sublimation Rates 1-S Figure 1-3. Radial Row Sublimation Rates 1-7 Figure 1-4. Radial Zone Sublimation Rates 1-8 Figure 2-1. Projection Method Example Chart 11-9 Figure 2-2. Visual Estimation Method Example Chart Il-Figure 3-1. Illustration of Student's t-Test 111-1 Figure 3-2. Effect of Sample Size on the Error of the Mean 111-4 Figure 3-3. Illustrative Plan View of Ice Bed, Showing Three Radial Zone Groupings of Ice Baskets (648 baskets each) 111-5 Figure 3-4. Plan View of Containment Building, Showing Proximity of Steam Generator and Pressurizer Compartments to Ice Condenser Bays 111-6 Figure 3-5. Effect of Visual Estimation Measurement Error on the Error of the Mean for Various Sample Sizes 111-1o Figure A-1. Typical Bay Arrangement and Identification A-2 Figure A-2. Typical Bay Map and Basket Identification A-3 Tables Table 0-1. Significant Aspects of the Ice Mass Technical Specification 0-s Methodology Table 1-1. Row-Group Sublimation Rates I-5 Table 1-2. Radial Row Sublimation Rates 1-6 Table 1-3. Radial Zone Sublimation Rates 1-8 Table 2-1. Altemate Mass DeterminatIon Technique Data Refreshment Criteria 11-7 Table 2-2. Projection Method Example Data 11-8 Table 2-3. Visual Estimation Method Example Data I1-I Table 3-1. Ice Basket Mass Measurement Random Error 111-7 Table 3-2. Illustration of Effects of Alternate Mass Determination Methods And Expanded Sample - Radial Zone A 111-8 Table 3-3. Ice Bed Masses from Sample Group 111-l1 Table 3-4. Ice Mass Sample Group 111-12 Table 3-5. Radial Zone A Sample Group 111-16 Table 3-6. Ice Mass Sampling Plan Recommendations 111-18 Table A-1. Example Ice Bed Data - For Reference Only A-4 Table A-2. Ice Mass Sample Group A-43 Table A-3. Example Calculations A-47 TOPICAL REPORT ICUG-001, Revision 2 iii June 2003

Topical Report ICUG-001 Application of the Active Ice Mass Management Concept to the Ice Condenser Ice Mass Technical Specification Nomenclature This topical report will utilize terminology that descnbes aspects of the supported technical specification methodology. In the interest of consistency, the following definitions apply to terms used throughout the report:

• Radial: Direction along a line drawn from the center of containment toward the outer containment wall.

Azimuthal: Direction along a circular line drawn from ice condenser Bay 1 towards Bay 24, or vice-versa.

Row: Linear population of ice baskets in the azimuthal direction; there are 216 baskets per row in an ice bed, with nine rows total.

Column: Linear population of ice baskets in the radial direction; there are nine baskets per column and nine colunms in a bay, with 216 columns total.

Accuracy: Generic term referring to the ability of a methodology to assess the mass of an ice basket.

Error: Statistical term referring to the numerical difference between an actual ice basket mass and its measured mass.

Random sample: A sample of ice baskets selected from the parent population of ice baskets in an ice bed, where each basket in the parent population has the same probability of being selected.

Stratified random sample: A sample of ice baskets selected from a defined sub-population of ice baskets, where each basket in the sub-population has the same probability of being selected.

Representative sample: A sample of ice baskets intentionally selected from specified areas of the ice bed population, such that all areas are equally represented.

• Ice mass: The total mass of ice that exists in a population of individual ice baskets, without the baskets themselves included (i.e., no tare weights).

• Radial Zone: A defined population of ice baskets encompassing all ice baskets in a given row or rows.

Bay-Zone: A population of ice baskets in a Radial Zone delimited by a given Bay.

Ice bed: The entire population of ice baskets, ice, and supporting structures in the ice condenser from the Lower Support Structure up to, but not including, the Intermediate Deck, End Walls, and Wall Panels.

• Stuck basket: An ice basket that is prevented from being physically lifted, due to either freezing (to the lattice structure) or mechanical impediment.

Obstructed basket: An ice basket that, due to excessive external surface ice or other blockage, cannot be inspected along its height.

TOPICAL REPORT ICUG-001, Revision 2 iv June 2003

• Alternate Mass Determination Technique: Any methodology employed to assess the mass of an individual ice basket other than physically lifting the ice basket.

Initial sample: A set of ice baskets chosen at random from a given Radial Zone as a part of the initial sample grouping for the Ice Mass Technical Specification surveillance requirement.

• Expanded sample: An additional set of sample baskets chosen at random from a given Radial Zone, with the initial sample set removed from the population.

• Alternate basket. An ice basket chosen to replace the initial sample basket, when the initial sample basket is stuck and obstructed.

• Mean: The average of a set of ice basket masses.

95% level of confidence (or confidence Interval):,5% confidence refers to an interval (x lb toy lb, orx lb or greater) which is calculated based on the number of samples, sample mean, sample standard deviation, and the confidence level (95% in this case), that aims to predict the actual mean for the entire population. The interval envelopes the actual mean of the parent population 95% of the time. Of all possible sample groups that could be chosen from the parent population, 95% of them would result in an interval that contains the actual mean ice basket mass for the parent population.

• Student's t-test Statistical procedure used to determine the parent population mean from the mean of a sample group at a prescribed confidence interval.

Error of the mean: Statistical term that designates the difference between the mean of a sample group and the mean of the parent population at a prescribed confidence interval.

Random error: A deviation from the actual value which occurs in a non-systematic manner.

Variation of the process: Statistical term that refers to the variation of the actual mass of the baskets throughout the ice bed.

Vaiation of the measurement: Statistical term that refers to the variation of the measured mass of an ice basket due to variations in the measurement technique.

Normality: The degree to which the sample distribution has the attributes of a normal distribution.

• Sampling without replacement: Taking samples from a parent population wherein each basket in the population can appear only once in the sample. Once a basket is selected from the parent population, it is removed from the candidate population of baskets for the next selection and therefore, it may not be selected again for the sample.

TOPICAL REPORT ICUG01, Revision 2 v

June 2003

Overview The Ice Condenser Utility Group (ICUG), consisting of members of all domestic ice condenser-owning utilities (Tennessee Valley Authority, American Electric Power, and Duke Energy), has collectively amassed nearly 150 years of operational experience in the ice condenser since D.C. Cook Nuclear Plant Unit 1 began commercial operation in 1975. Since then, eight more ice condenser containments have been added to the fleet, all of which are currently operational. The original technical specification verifying total ice mass and distribution in the ice bed has been extensively reviewed by both the NRC and ICUG.

While it is considered adequate to show operability, some concepts from which the original specification was derived have changed, and others need clarification. Several potential changes to the specification have been identified that allow the application of the industry's accumulated operational history and experience, as well as provide an improved process for verifying total ice mass. This topical report will address those improvements to the Ice Mass Technical Specification and show the inherent linkage to plant-specific maintenance practices.

Acfive Ice Mass Management As operational history shows, sublimation rates are quite significant in certain areas of the ice condenser and essentially non-existent in others, and a large effort is required to maintain the ice bed mass inventory each outage. This maintenance effort, however, restores the ice bed mass and distribution characteristics required for continued operation. The process of replenishing the ice baskets to restore ice bed mass based on the monitoring of varying sublimation rates during the cycle is the basis for the Active Ice Mass Management (AIMM) concept.

This concept is rooted in the industry's adherence to the OCFR50 Appendix B requirements governing maintenance to a nuclear safety-related system. Existing AIMM practices manage each ice basket in the ice bed above the required mean mass supporting the safety analysis. It is a natural follow-on, then, to revise and maintain the technical specification to accommodate AIMM methodology and at the same time introduce industry operational experience. For example, the original specification describes an "as-left" (post-maintenance) surveillance of total mass and distribution, which requires that an assumed uniform sublimation (and weighing error) allowance be included in the surveillance limit. In this manner, ice mass is shown to be adequate for the coming operational cycle. The new approach uses an "as-found" (pre-maintenance) surveillance. This improvement accomplishes several things:

> An as-found surveillance shows the adequacy of total ice mass for the current operational cycle. The total mass surveillance limit is the actual minimum requirement for ice bed operability.

> The sublimation allowance and mass determination accuracy details become plant-specific procedural entities (allowing them to vary), which is more precise than assuming a uniform sublimation rate across the ice bed.

> The performance of an as-found surveillance inherently verifies the propriety of a plant's Active Ice Mass Management process, since compliance with the technical specification shows awareness of varied ice bed sublimation rates.

> Radial zones in the ice bed can be defined for statistical purposes that delineate groups of ice baskets with similar expected as-found mean mass and a reasonable standard deviation. With ARAM methodology ensuring replenishment of needed mass, these zones facilitate an accurate assessment of total ice bed inventory.

The result is a technical specification that appropriately combines accumulated experience, knowledge of the ice condenser design basis, and the use of statistical methods to support an industry-consistent, simplified surveillance and, in turn, enhanced Unit reliability. In this regard, while the concept of a consistent technical specification surveillance is an important industry objective, plant-specific TOPICAL REPORT ICUG-001, Revision 2 0-1 June 2003

maintenance techniques used in implementing AIMM methodology must necessarily be allowed to evolve independently. These techniques are constantly being improved at each plant, and the exchange of technical information facilitated through the ICUG ensures industry peer review. Primarily, it is the Ice Mass Technical Specification itself that must be consistent in its intent and application.

Industry ChalIences The design of the ice condenser system constantly challenges industry initiative, given that operational experience has rewritten some of the original assumptions regarding ice bed behavior. While the ice condenser itself appears passive, sublimation, frost build-up, and a saturated environment all take their toll over the course of an operational cycle. Ice bed maintenance processes contribute further, the use of vibrators and thermal drills to replenish sublimated ice baskets creates an outfall of ice/water, which, while expected, tends to make other maintenance-related activities more time-consuming.

Among the most significant challenges faced by the industry in verifying total ice mass are frozen (or "stuck") ice baskets. The situation occurs when external basket surfaces become covered with ice and frost and effectively freezes them to the lattice structure, rendering some baskets incapable of being physically lifted unless a significant amount of force is used. Stuck baskets also occur when support steel or some other mechanical impediment hinders vertical basket movement. This prevents the use of a lifting rig to determine mass, which is the method of choice by the industry since it is relatively fast and the most accurate. The limitation that results has necessitated the selection of representative altemate baskets for the statistical sample, the use of which over time has been implemented differently by individual plants due (in part) to vague original guidance provided. This has created interpretation inconsistencies across the industry. Compounding the issue is the knowledge that all ice baskets that require servicing are replenished during ice bed outage maintenance, but not all can be used to verify the total ice mass: some baskets' mass cannot be ascertained by lifting (stuck) and others were excluded from the sample group by design. The industry realized that a basket that has been just replenished, but is stuck, does not constitute a threat to the design basis of the ice condenser. Likewise, a recently replenished basket that resides in a historically low sublimation region of the ice bed, but is stuck, does not constitute a threat. In the larger view, no basket-stuck or otherwise-is a threat to ice bed operability unless the amount of ice in it (or lack thereof) is indicative of a localized area of degraded ice bed mass or contributes to the surveillance requirement for total mass not being met.

The technical specification approach supported by this topical report resolves this by introducing altemate mass determination techniques for ice baskets that cannot be physically lifted. These techniques-the detailed development of which are plant-specific-currently have been designed to utilize both existing historical information (such as in the use of trending software for basket mass projections) and visual profiling/estimation. The methods are valid forms of ice basket mass determination as long as the accuracy of the methods is properly accounted for in both the actual measurement and the statistical sampling plan.

In this respect, it is also recognized that even with alternate mass determination methodology defined, there will be occasions when no currently available technique can ascertain the mass of ice in some baskets, due to a physical obstruction or other situation (such as external frost/ice build-up on a historically stuck basket that prevents visual inspection). As also allowed in previous versions of the technical specification, in these cases an alterate sample basket from the vicinity of the initial sample will need to be selected and therefore guidelines adopted. To accomplish this, the altemate selection criteria have been designed around the Radial Zone concept, in which baskets in the same Radial Zone generally have similar mass. Alternate selections are representative of initial selections as long as they have the same probability of being selected as an initial selection and can be expected to have similar characteristics as an initial selection. Limiting an alternate selection to the same Bay as the obstructed original selection further develops the criterion, and allows inclusion of baskets from previously excluded TOPICAL REPORT ICUG-001, Revision 2 0-2 June 2003

rows: all ice baskets in the ice bed are included in the sampling plan while the original version exempted 33% (radial rows 3, 5, and 7) of the ice bed from the parent population. In addition, the use of alternate selections is restricted to prevent repeated use of the same alternate basket from affecting statistical confidence.

A further disparity in the historical methodology required each statistically sampled basket to contain the specified amount of ice, while the Bases allowed for individual baskets to be "light" (i.e., less than the technical specification required minimum mass) if baskets in the local area were sufficiently full. This contradiction also led to differing industry interpretations, even though the original intent was, as described by the technical specification bases, to prevent localized gross degradation of the ice bed. The technical specification methodology presented here treats this contradiction by recognizing that the two primary concerns of the ice mass design basis-and therefore the two required surveillances-are the presence of sufficient total ice mass in the bed distributed appropriately to accommodate the overall DBA response, and a sufficient minimum mass in any individual basket maintained to prevent localized areas of degradation that might challenge the DBA containment pressure response.

The requirement for the overall DBA response is met by determining total ice mass in the bed based on a sampled group. In this manner, the word "each" is eliminated from the operability requirement, and individual baskets can sublimate during an operating cycle to whatever level their relative position in the ice bed dictates. Conversely, the minimum individual basket mass requirement stipulates a minimum mass of ice for each of the statistically sampled baskets so that a minimum amount of ice in the basket is verified to be present. The use of each in this instance is appropriate, since the containment analysis is primarily concerned with localized degradation (i.e., a cluster of baskets with degraded mass) and the sampled group is a valid representation of the entire Radial Zone under surveillance. As noted previously, AIMM practice will manage each basket above the required safety analysis mean, such that no individual basket would be expected to sublinate below this mean value. If a basket sublimates below the safety analysis mean value this instance is identified within the plant's corrective action program, including evaluating AIMM practices to identify the cause and to correct any deficiencies. If a basket sublimates below the minimum individual basket mass requirement, then this condition is TS prohibited, necessitating reporting per the requirements of OCFR50.73 in addition to corrective action program determination of cause and appropriate corrective actions. Certain individual baskets in the cornes of the ice bed would typically pose the greatest challenge to maintaining their stored ice mass above the safety analysis mean, due to the relatively high sublimation rates in these areas. However, AIMM practice would generally identify these baskets for servicing every outage, thereby enabling the ice mass in these baskets to be maintained above the safety analysis mean, which would prevent any challenge to the surveillance requirements.

Summary of Sqnificant Asnects The approach to the Ice Mass Technical Specification supported by this topical report is in some ways similar to the original, but in others, very different. The subdivision of the ice bed into Radial Zones for the purpose of sampling, each comprising a third of the ice baskets in the bed, recognizes that the original representative sample did much the same thing by defining the sampled radial rows to be 1, 2, 4, 6, 8, and 9, which essentially outlined three regions of generally similar characteristics. Industry commitments to manage the ice mass in each basket above the required safety analysis mean, a statistically random sample in each Radial Zone, and a defined minimum individual ice mass per basket combine to become the basis for verification of appropriate ice distribution in lieu of a limited azimuthal row-group surveillance. The addition of alternate mass determination techniques for individual baskets and a more restrictive (same Radial Zone, same Bay) procedure for utilizing alternate baskets when original samples are stuck and obstructed clarify two areas of inherent weakness in the original surveillance. These and other enhancements provide a much improved surveillance that is simpler and more clearly defined than the original.

TOPICAL REPORT ICUG-001, Revision 2 0-3 June 2003

Figure 0-1 charts the strategies forming the basis of this technical specification methodology for Figtre 1 charts thie strategies fomning the basis of tis technical specification methiodology for verification of ice mass.

Figure 01. Ice Mass Surveillance Strategy TOPICAL REPORT ICUG-001, Revision 2 June 2003 0-4

Table 0-1 identifies the most significant aspects of the technical specification methodology supported by this topical report:

Table 01. Significant Aspects of the Ice Mass Technical Specification Methodology o The surveillances used to ascertain ice mass and distribution are performed in the as-found (pre-maintenance) condition, as opposed to the as-left (post-maintenance) condition o The minimum operability requirements for total ice mass are defined to better reflect the design basis o Sublimation allowances and mass determination accuracy are accommodated by plant-specific maintenance procedures o A surveillance for miniimum total ice mass in the bed assures the initial conditions of the DBA analyses o A surveillance for minimum ice mass in each individual basket prevents localized degradation to avoid any challenge to the DBA containment pressure response o For the purpose of statistical analysis, the ice bed is divided into three Radial Zones of three sequential rows each to isolate basket populations that have similar mass characteristics o Proper azimuthal distribution of ice in the ice bed is no longer assessed by a separate surveillance requirement; it is implemented through established industry-wide maintenance practices that manage each ice basket above the required safety analysis mean and confirmed through as-found random sampling techniques o All ice baskets in the parent population are subject to random statistical sampling, as opposed to only two-thirds of the population subject to representative sampling o Methods of determining the mass of individual sample baskets other than manual lifting are allowed o The process for selecting an alternate basket for the statistical sample when the mass of an initial sample basket cannot be ascertained by any method has been revised, restricting alternates to those baskets in the same Radial Zone, same Bay as the initial sample and limiting their re-use as an alternate from prior surveillances Aprlicability to Ice Condenser Plants The generic industry position developed and presented in this topical report utilizes historical operational information and data obtained from Tennessee Valley Authority's Sequoyah and Watts Bar Nuclear Plants, and Duke Energy Corporation's McGuire and Catawba Nuclear Stations. Specific historical ice bed data from D.C. Cook Nuclear Plant was not included due to past configuration control and consistency issues that have since been resolved. Generic data and trends from the Cook plant, however, are consistent with the rerainder of the industry and as such were included in assessing the industry position presented herein.

The concept of Radial Zones was developed by the industry based on collective historical sublimnation data and the need for a more accurate assessment of ice bed mass as it relates to containment safety analyses and active maintenance practices. Currently, the Design Basis Accident (DBA) containment response model for the short-term blowdown phase for all ice condenser plants is based on Westinghouse Electric Company's Transient Mass Distribution (TMD) code. With the exception of the Duke plants, which utilize a previously approved GOTHIC model, the long-term phase of the DBA is modeled by Westinghouse's Long Term Ice Condenser (LOTIC) codes. With this foundation, all industry plants can adopt the Radial Zone concept-and the ice mass derived therefrom-for the basis of their ice mass technical specification. While this topical report describes the industry-standard Radial Zone TOPICAL REPORT ICUG-001, Revision 2 June 2003 0-5

configuration (three Radial Zones containing three sequential rows of ice baskets each), it is noted that more refined configurations are possible using similar technical justification. Any Radial Zone configuration different than the industry standard, however, is subject to the same statistical sampling plan and altenate selection criteria described herein.

TOPICAL REPORT ICUG-001, Revision 2 June 2003 0-6

I Ice Mass Requirement Design Basis and Industry Data Purnose /Scone The purpose of this Section is to describe the historical development of the ice mass requirement design basis and provide the link to the Ice Mass Technical Specification and AIMM methodologies. Analysis of historical operational data is performed to support the approach.

Historical sublimation data from Duke Energy's McGuire and Catawba Nuclear Stations and Tennessee Valley Authority's Sequoyah and Watts Bar Nuclear Plants was compiled and normalized to reflect a typical ice condenser plant. The normalized data from these seven units of record is generally indicative of any domestic ice condenser, including the two at D.C. Cook Nuclear Plant. Concepts introduced in this Section are based on current industry practice, sublimation rate analyses, design basis interpretation, and operating experience.

Design Basis The ice condenser containment is analyzed for the limiting design basis accident (i.e., a double-ended guillotine reactor coolant pipe break loss-of-coolant accident, or large-break LOCA) for confirmation of pressurization integrity in accordance with IOCFR50, Appendix A General Design Criterion 50. The containment is analyzed for both short-term and long-term pressurization effects.

The short-term containment pressurization analysis is performed using the Westinghouse Transient Mass Distribution (TMD) analysis code. The short-term analysis, whose actual duration is a function of plant specific parameters but is modeled as a ten-second event, establishes the peak pressure differential across the ice condenser and reactor building structures that separate lower containment from upper containment.

The analysis confirms the ice condenser and related structures will maintain their structural integrity under peak differential pressure loads caused by the compression of the lower containment air volume as it is forced into upper containment through the ice condenser as a result of the mass and energy released in the initial seconds of a large-break LOCA. The short-term containment integrity analysis assumes a fixed flow area through the ice condenser, which establishes the design basis requirement for ice condenser flow passage area. Westinghouse Electric Corporation tested the capability of the ice bed to withstand the blowdown energy release at their Waltz Mill Facility and documented the results for each plant (Ref. 14-18).

The long-term containment pressurization analysis is performed using the two-dimensional Westinghouse Long Term Ice Condenser Containment (LOTIC) analysis code (the three-dimensional GOTHIC analysis code is used for the Duke plants). The long-term analysis evaluates containment pressurization beginning with reactor coolant system blowdown, and continues through ice bed melt-out and subsequent containment building pressurization control using the containment spray and residual heat removal systems. The analysis is used to confirm that the peak containment pressure remains below the design limit at all fimes following a large-break LOCA. The long-term analysis assumes an initial ice mass in the ice condenser that suppresses containment pressurization as the ice bed melts. At the time that sections of the ice bed begin to completely melt out, the emergency core cooling systems are realigned from the refueling water storage tank to the containment recirculation sump. Following complete ice bed melt-out of all sections, containment spray systems and injection systems suppress containment pressurization with active heat removal being provided by emergency core cooling heat exchanger(s). The assumed ice mass in the LOTIC/GOTHIC analyses must be sufficient to limit the peak containment pressure below the design basis limit following ice bed melt-out, and typically also delay melt-out of complete sections of the TOPICAL REPORT ICUG001, Revision 2 1-1 June 2003

ice bed until emergency core cooling systems are aligned to the containment sump. One of the fundamental assumptions of the two-dimensional LOTIC model is that only a minimal amount of the mass and energy released in the lower containment bypasses the ice condenser until the time of ice bed melt-out of complete sections. While it is understood that the ice bed will not likely melt out evenly over the course of the DBA, early melt-through of sections of the ice condenser could reduce the modeled efficiency of the ice condenser, resulting in increased containment pressurization. Early melt-through of the ice bed will not occur as long as 1) the ice condenser and related structures maintain their structural integrity (as demonstrated by the short-term TMD containment analysis), and 2) enough ice mass is sufficiently distributed such that localized degraded regions of mass do not exist in the ice bed. In this manner, the LOTIC/GOTHIC analyses assumptions and methodology establish the design basis requirements for total ice mass.

Historically, an as-left ice mass surveillance was used to verify that the design basis parameters would be met throughout the coming fuel cycle. The as-left Technical Specification ice mass requirement contained an added sublimation allowance for anticipated ice loss through the cycle, and an additional conservative allowance to account for mass detennination uncertainty.

Orici,nal Ice Mass Technical Speclifcation Requirements Based on historical industry experience (references 1 and 2), a 144-basket sample size resulted from two separate increases. D.C. Cook Nuclear Plant Unit 1 was the first ice condenser containment to operate, and ice mass was closely monitored. For two years in the mid-1970s, ice mass was obtained and analyzed at three-or four-month intervals (references 3 - 7). The first ice mass Technical Specification, supplied by Westinghouse Electric Corporation as an experimental version, required that a total of 60 ice baskets be weighed from the ice bed parent population. After the initial evaluation program was complete in 1975, ice bed sublimation patterns were recognized as significant; the sample size was increased from 60 to 96 and created a representative sample, with one basket each taken from radial rows 2, 4, 6, and 8 in each of the 24 bays. Then, in 1976, technological advances allowed the inner and outer radial rows (rows 1 and 9) to be lifted, which resulted in additional ice mass data collection. Evaluation of the data indicated that the most active sublimation occurred in these two rdial rows. The technical specification was again revised in 1977, increasing the sample size from 96 to 144 ice baskets to add samples from the two outer radial rows. The 144-basket sample configuration was considered representative of the parent population and included six baskets from each of the 24 ice condenser bays, consisting of one basket from each of radial rows 1, 2, 4, 6, 8, and 9 per bay.

This representative sample was used to calculate the total ice bed mass with a 95% level of confidence, as determined by ensuring that each individual basket mass in the sample group was in compliance with the surveillance requirement's per-basket limit. The individual sample basket masses were also used to ensure the azimuthal distribution of ice was reasonably uniformL This was accomplished by subdividing the ice bed into Row-Groups, and ensuring the limit per basket for each was met. The Groups were defined as follows:

Group 1 - bays 1 through 8 Group 2 - bays 9 through 16 Group 3 - bays 17 through 24 These groups align with the location of the Steam Generator compartments, the Pressurizer compartment, and the Reactor Coolant Pumps as shown in Figure 1-1. The groups are also consistent with the sectored initial ice loading strategy employed by the D.C. Cook plant in 1974.

TOPICAL REPORT ICUG-001, Revision 2 1-2 June 2003

Figure 1-1. Typical Plan View of Containment Building As noted previously, the original ice mass technical specification required individual sampled basket masses meet the surveillance requirement linit in order to verify total mass. In addition, these masses were used as the verification that a degraded localized region did not exist in the ice bed that would challenge the DBA pressure response. If a basket in the 144-basket statistical sample was found to weigh less than the required individual limit (described as light'), the sample was to be increased in the localized region (i.e., the affected Bay) by 20 baskets. The averaged mass of the 20 additional baskets and the "light" basket was then required to meet the surveillance limit.

Historical Data In the effort to revise the original Ice Mass Technical Specification, the industry agreed to evaluate historical data to develop a surveillance that is consistent with evolved maintenance techniques and operating experience. Since most domestic ice condenser plants have implemented the use of the trending software ICEMANrm, which was developed by Duke Energy Corporation and Framatome ANP, it will be used to compile historical industry data.

TOPICAL REPORT ICUG-001, Revision 2 June 2003 I-3

The ICEMANT program is an ICE condenser MANagement system that provides for scheduling and managing ice condenser maintenance activities such as ice mass determination, ice basket replenishing, basket maintenance, and flow channel inspection and cleaning. It also provides technical specification analysis methodology and specific reports required by maintenance procedures, regulations, and administration. ICEMANTm maintains a record of each basket's historical "life", which aids in active management of the ice bed mass.

For this development, historical ice basket sublimation data was taken from each plant's ICEMANW database and averaged to represent typical ice basket sublimation rates. This was accomplished by first defining valid data from each unit's database. Valid ice basket mass data, for the purposes of analysis, is considered to be individual baskets having more than 1,400 recent consecutive days (about three cycles) of sublimation information. These criteria ensure that cycle-to-cycle variances are not dominant and the effects of AIMM practice are included. Then, ice baskets with valid data were combined into a single database, providing each basket with as many as seven sublimation rate entries (one for each ice condenser unit of record). Sublimation rates were then averaged resulting in one data set containing 1,944 ice baskets, each with an associated industry mean basket sublimation rate. For clarity, ice baskets that have only one entry were assumed to be the industry average.

Historical Dafa Analvsls Historical technical specification data (which excluded baskets in radial rows 3, 5, and 7 from the sample group) was used as the basis for a normal operating cycle sublimation analysis, since industry data for these rows is the most complete. Industry mean basket sublimation rates were applied to the previously defned Row-Groups, and the Row-Group mean sublimation rates and associated standard deviation from a population of 72 baskets per group calculated. Table 1-1 shows a comparison of the mean sublimation rates for each Row-Group and each radial row, where row 9 represents the row adjacent to the inner Crane Wall and row 1, the outer Containment Wall. The mean radial row sublimation rates shown in Table 1-1 are based on a row population of 216 baskets. Figure 1-2 is a graphical representation of the same data.

Table 1-1. Row-Group Sublimation Rates Radial Mean Sublination Rate Standard Deviation Row (lb/18 month)

(lb/18 nmonth) 9 Row 153 56 Group I 176 42 Group 2 102 36 Group 3 181 51 8

Row 97 22 Group 107 19 Group 2 76 12 Group 3 107 14 6

Row 38 10 Group 41 II Group2 35 7

Group 3 38 11 4

Row 16 12 Groupl 17 12 Group 2 14 4

Group3 1

7 16 2

Row I11 25 1

14 25 Group2 4

7 Group 3 15 33 Rayw 16 30 rO I

25 35 Group2 6

13 F

Group 3 16 34 TOPICAL REPORT ICUG-001, Revision 2 I-4 June 2003

Figure 1-2. Row-Group Sublimation Rates 180 120 iGroup 1 100 inGrouP 2 E-Group 3 RwRow Avg.

80 80 40 20 0

Row 9 Row 8 Row 6 Row 4 Row 2 Rowi1 As shown in Table 1-1 and Figure 1-2, historical industry sublimation data indicates effects in both the radial and the azimuthal directions across the bed, an expected behavior primarily due to the proximity of heat sources in Containment. While the end wall bays (bays 1 and 24) and Groups immediately adjacent to the Steam Generator and Pressurizer compartments (Groups 1 and 3) show some azimuthal variance, these groups represent two-thirds of the ice bed. As a result, no individual bay exhibits a significantly disproportionate trend due to the azimuthal variance.

If the ice mass surveillance is performed on an as-found (pre-maintenance) basis, then the sublimation allowance is no longer needed in the technical specification and it can be moved to plant maintenance procedures that are maintained per the requirements of 10CFR5O, Appendix B and 10CFR5O.59. This allows ice baskets to be serviced in the plant maintenance program based on their individual basket sublimation rates, as opposed to assuming all baskets sublimate uniformly across the bed (an assumption clearly dismissed by the industry operating experience depicted in Figure 1-2). The practice of managing individual basket sublimation in order to maintain a relative distribution of ice across the bed is the foundation of the Active Ice Mass Management (AIMM) concept.

AIMM Methodoloaq In order to perform appropriate replenishment activities on the ice bed each outage, the number of baskets needing to be serviced must be identified. Replenishment "triggers" vary from plant to plant due to variations in specific sublimation rates, but at all plants the as-found ice mass in each basket of the bed must be assessed prior to assigning replenishment scope. As shown in Figure 1-2, there are a significant number of baskets that will not need ice replenishment every outage (such as those in rows 1-6).

However, the current mass of ice in these baskets must still be determined in order to predict when they will need replenishment in the future. This process (assigning replenishment scope to the current and future outages based on current basket mass and known sublimation trends) is an active management TOPICAL REPORT ICUG-001, Revision 2 1-5 June 2003

process, requiring that plants know the specifics behind their ice bed's behavior patterns. In most cases, each individual basket in the ice bed has a known sublimation behavior pattern associated with it, based on its specific location. Upon determining the as-found ice mass for a basket in the bed, plant personnel then compare that value to the required safety analysis mean value and apply that basket's sublimation trend to project its mass forward through the coming cycle. Any individual basket's ice mass that is projected to sublimate to or below the safety analysis mean mass value is serviced during the current outage. This is how AM practice maintains the ice mass in each individual basket above the required safety analysis mean.

Determination of Basket Mass in AIMM Practice As noted previously, the preferred method for basket mass determination is via a load cell due to this method's relative speed and accuracy. As it requires the baskets to be free to be lifted, the use of this method is limited in areas of the bed where frequent servicing has rendered some baskets unliftable. In these areas, either historical sublimation trends are used to project a basket's mass to the present, or it is visually inspected (full length via camera) and its mass estimated. Since the historical technical specification surveillance requirements were performed in the as-left condition, all baskets used in satisfying the surveillance after servicing were required to be free so that a load cell could be used. In many cases, this resulted in the use of alternate selections in the areas where stuck baskets are common.

The technical specification approach supported by this topical report is an as-found surveillance, providing an opportnity for the industry to document these alternate methods of mass deternination for satisfying the surveillance requirements. This is discussed in more detail in Section I.

The Radial Zone Concept Technological advances (such as ICEMANTm) have allowed the industry to further develop AIMM methodology by simplifying the evaluation of empirical data and depicting long-term ice bed behavior.

As was done previously in Table 1-1 with defined azimuthal Groups, mean industry data can be used to show the radial row mean sublimation rates for each radial row (see Table 1-2). These sublimation rates are based on a population of 216 baskets per radial row and is consistent with data presented in Table 1-1, where radial row 9 designates the row adjacent to the Cane Wall. The data is shown graphically in Figure 1-3.

Table 1-2. Radial Row Sublimation Rates Radial Row Mean Sublimation Rate Standard Deviation (lbst18 months)

(lbs/18 months) 9 153 56 8

97 22 7

60 10 6

38 10 5

24 18 1

4 `T~~

16 12 3

11 18 2

14 25 1

16 30 TOPICAL REPORT ICUG-001, Revision 2 1-6 June 2003

Figure 1-3. Radial Row Sublimation Rates (lbs/18 months) 180 160 140 120 100 so so 40 20 0

III:

W0 Row 9 Row Row 7 Row Row 5 Row 4 Row 3 Row 2 Row Figure 1-3 clearly shows that certain radial rows sublimate at markedly different rates than other rows, with the most pronounced effect in the innermost radial rows 7, 8, and 9. The industry recognized that isolating these three radial rows would provide a "radial zone" that behaved, for all intents and purposes, as a separate entity. Through AIMM practice, the baskets in radial rows 7, 8, and 9 are the most frequently serviced due to this sublimation rate difference, but not all rows are serviced at the same time (i.e., the same outage). It became apparent that because of this inherent replenishment schedule, these three rows contained similar mean mass at any given point in time. With radial row 9 serviced the most frequently, and rows 7 and 8 serviced less frequently, every ice basket in the "radial zone" could be used as a reasonable as-found (pre-maintenance) representative of the zone. The new ice mass surveillance, then, could easily be defined in terms of Radial Zones, where each Radial Zone was comprised of rows of ice baskets that historically conveyed similar mean mass for analysis purposes.

The Radial Zone concept was further supported by the idea that statistical analysis could be performed on individual Radial Zones to determine total ice bed mass with 95% confidence, which would considerably simplify the surveillance requirements. This led to a generic three sequential radial row, three Radial Zone configuration, which was based on the data depicted in Figure 1-3. It is noted, however, that this configuration is not the only one that will work, other, more refned approaches can be made with a similar technical basis.

To illustrate the adopted generic configuration, Radial Zones are defined such that Zone A contains Rows 9, 8, and 7; Zone B contains Rows 6, 5, and 4, and Zone C contains Rows 3, 2, and 1. Applying this concept to industry historical data results in a profile of mean sublimation rates, as shown in Table 1-3 and Figure 1-4.

TOPICAL REPORT ICUG-001, Revision 2 June 2003 1-7

Table 1-3. Radial Zone Sublimation Rates Radial Zone Mean Sublimation Rate Standard Deviation (lb/l8 months)

(lbs/18 months)

___= A 103 52 B

26 14 C

14 25 Figure 1-4. Radial Zone Sublimation Rates 120 100 so 40 20 a-

-~ ~ ~~~~

r a

4

.i I

I ZOe A

Zof*

zone C The concept of Radial Zones is also applied to the alternate basket selection criteria, which provides for an alternate basket selection for the statistical analysis in the event an initial sample selection cannot be accessed. Since each Radial Zone consists of baskets having similar mean mass, all baskets in that Radial Zone are considered to be statistically representative for sampling purposes. This approach is discussed further in Section II.

ReGIons of Localized Degraded Mass A surveillance that requires a minimum total ice mass in each Radial Zone assures the initial conditions of the DBA analyses, and also assures that the ice mass is appropriately distributed across the three Radial Zones. A separate surveillance, addressing the potential effects of a localized area of baskets with degraded mass, adds assurance that AIMM practice is being implemented appropriately. As described previously, through AIMM methodology individual basket mass is managed above the required safety analysis mean value. The AIMM methodology provides defense in depth in complying with the surveillance requirement and minimizing any occurrences of baskets with ice mass less than the required safety analysis mean. The original licensing basis for the ice bed provides the concept that the DBA containment pressure response is relatively insensitive to variations in ice mass (Ref. 19). This concept is evident by the original Technical Specification provision for the treatment of "light baskets."

In an effort to provide quantitative bases to link this concept to DBA safety analysis, Duke Energy ran a series of three-dimensional GOTHIC sensitivity runs (Ref. 21) using the McGuire Nuclear Station TOPICAL REPORT ICUG-001, Revision 2 June 2003 I-8

containment model. For the purposes of showing containment pressure response sensitivity to localized degraded mass conditions of varying severity, the GOTHIC results can be applied to all domestic ice beds.

For each of these sensitivity runs, an entire end sector of ice baskets (2.75 ice condenser bays side-by-side at the far end of the bed) was degraded, and the worst postulated DBA break positioned right under this region. As the GOTHIC analysis is a three-dimensional model and allows cross-flow between bays, choosing the end sector limited the advantage of steam cross-flow to only one adjacent sector after the degraded region melted through during the analyzed DBA transient. Three separate cases were defined:

Case 1: All baskets in Radial Zone A bounded by the far-end GOTHIC sector (2.75 bays) contain 600 lb of ice each at the onset of the DBA. This represents 75 baskets, all grouped together, positioned over the break location. The results for this run showed that the resulting peak containment pressure was essentially unchanged, staying within about /2 % of the baseline case for McGuire.

Case 2: All baskets in Radial Zone A bounded by the far-end GOTHIC sector (2.75 bays) contain 400 lb of ice each at the onset of the DBA. This represents 75 baskets, all grouped together, positioned over the break location. The results for this run showed that the resulting peak contaimnent pressure increased, but was within about 2 % of the baseline case for McGuire.

Case 3: All baskets bounded by the far-end GOTHIC sector (2.75 bays) contain 400 lb of ice each at the onset of the DBA. This represents 225 baskets (all three Radial Zones), all grouped together, positioned over the break location. The results for this run showed that the resulting peak containment pressure increased, but was within about 21/2 % of the baseline case for McGuire.

These results quantify the relative insensitivity of the ice condenser DBA containment pressure response to extreme ice mass variances, including worst-case break and mass variance locations. As described previously, via AIMM methodology each basket is managed above the required safety analysis mean mass, so that variances of this severity due to maintenance practices are highly unlikely. Given this, a plant transient significant enough to open the Lower Inlet Doors is the only mechanism that might create the extent of degraded conditions depicted by these runs, and a transient significant enough to open the Lower Inlet Doors would be annunciated in the Control Room, initiating prompt corrective action.

However, because the sample baskets randomly selected in a Radial Zone are statistically averaged to satisfy the surveillance requirement for mean total ice mass, the Technical Specification technically allows some individual baskets to be below the safety analysis mean provided there are other higher-mass baskets in the sample to account for them. Therefore, a limit is established on the minimum allowed ice mass in any basket to assure that the potential for melt-through of any localized area of the ice bed will be consistent with the original DBA analysis concepts. For this reason, a minimum individual basket mass limit of 600 lb per basket is established as a separate operability requirement, such that there are essentially no effects on DBA containment pressure response. This as-found surveillance for minimum ice mass in any individual basket assures the bed condition is at all times consistent with the initial conditions of the DBA analyses, by limiting localized degradation that might challenge the DBA containment pressure response.

Conclusions Existing ice condenser design basis requirements show that the ice mass technical specification is satisfied as long as both the short-term and long-term phases of the DBA are accommodated by sufficient ice mass in the bed. Therefore, the new Ice Mass Technical Specification contains surveillance requirements that provide assurance the ice mass present in the ice bed at any given time, with a 95%

level of confidence, is sufficient to mitigate the overall DBA response. Specifically, the operability surveillances will be performed when necessary in the as-found (pre-maintenance) condition.

TOPICAL REPORT ICUG-001, Revision 2 1-9 June 2003

The minimum individual basket mass surveillance requirement is based on the minimum amount of ice needed in each basket to avoid localized regions of degradation in the ice bed that might challenge the DBA pressure response. This limit is derived from sensitivity runs performed using the three-dimensional GOTHIC analytical code. Concurrent assurance that localized regions of gross degradation do not exist in the ice bed is given via Active Ice Mass Management (AIMM) methodology, which is based on current industry maintenance practice and asserts that the ice mass in each basket in the ice bed will be managed above the required safety analysis mean, and serviced prior to reaching this limit. Therefore, the methodology for the requirement of minimum individual basket mass has two elements: 1) active maintenance practice (AIMM) that manages each basket to the required safety analysis mean, and 2) a defined surveillance minimum limit of 600 lb per basket.

Assessment of total ice mass and distribution in the ice bed is facilitated by segregating the ice bed into Radial Zones, which provides basket sub-populations with similar characteristics. Individual baskets can, as a result, sublimate according to their relative position in the bed and remain operable provided minimum individual basket mass limits are maintained and the total ice bed mass requirements met. The generic Radial Zone configuration adopted by the industry is a three-Radial Zone, three sequential row array based on historical sublimation and mass data from the plants, and in addition to providing enhanced mass assessment provides assurance of appropriate mass distribution.

An as-found (pre-maintenance) surveillance that verifies the total ice mass needed to mitigate a design basis accident will require that each plant be cognizant of ice basket sublimation rates and the accuracy of mass determination methodology. Sublimation allowances for upcoming cycles and treatment of mass determination uncertainty will be maintained procedurally at each site.

TOPICAL REPORT ICUG-001, Revision 2 June 2003 1-10

II Ice Basket Mass Determination Methodology PurposelS cope This Section describes the methods utilized to determine individual ice basket mass for the Ice Mass Technical Specification surveillance requirements, and provides a standard for developing, quantifying and maintaining the uncertainty for each of these methods. A description of available mass determination techniques is provided, along with a generic estimate of each technique's uncertainty based on analyzed industry data, which supports their use in the Statistical Sampling Plan (Section II) and in establishing a 95% level of confidence in the total ice bed mass. The methods analytically considered are manual lifting, basket mass projection using historical data and trending software (i.e., Excel spreadsheets, ICEMAN Tm, or other), and visual inspection. The treatment in this Section of the uncertainty in the mass determination techniques provides a large range within which other methodologies can be developed as the industry's experience grows. The quantitative details regarding the determination of ice basket mass and associated uncertainty are based on the accumulation of actual field data and therefore must be maintained in plant-specific procedures in accordance with IOCFR50, Appendix B. This topical report provides the associated methodologies that are the standard within the industry.

The generic analysis herein is based on ice mass data (collected via lifting, visual inspections and software projections) from the last refueling outage at any plant prior to February 2001. As noted previously basket mass data and mass determination technique uncertainties for subsequent plant outages will necessarily change; however, the general trends and conclusions remain valid.

Discussion Preferred Ice Mass Determination Method Historically, the determination of ice basket mass and the collection of ice mass data have been accomplished through manual lifting of the basket. This method provides the fastest and most direct way of determining ice mass. In this process, the ice basket is raised by its top with a lifting rig, which is attached to a load-measuring cell (for indication of the mass). For most baskets, a hoist is used for the lift; a hydraulic cylinder is used for less accessible basket locations. The load cells are calibrated via plant procedures conforming to 10CFR50, Appendix B requirements.

The manual method works well unless the basket selected is stuck and cannot be lifted without exceeding established maximum lifting force limits. For ice baskets that are stuck, either the mass of the selected basket must be ascertained by some alternative means, or a representative alternate basket selected within the guidelines and limitations discussed in Section III. If an alternate mass determination technique can ascertain the mass of ice in a basket, then the presence of stuck ice baskets is not relevant to the surveillance requirements.

Altemate Ice Mass Detennination Methods In general, a valid alternate basket mass determination technique must have the following three qualities:

1. The technique must be predictable, showing that the uncertainty associated with the methodology is based on sound analysis that is maintained to account for current experience levels, including actual accumulated field data, TOPICAL REPORT ICUG-001, Revision 2 II-1 June 2003

2. The technique must be repeatable, showing that its continued use does not generate values consistently outside the established uncertainty of the method, and

3. The technique must be shown to apply to the specific ice bed under surveillance, showing that the methodology is supported by valid local data.

As noted in Section I, ICEMAN7h is a software program that trends ice basket mass histories and can be utilized to project future ice basket mass based on individual sublimation rates and previous ice basket mass data. Likewise, other software applications can be used, such as Excel spreadsheets or similar commercially available products. Any of these utilized applications are maintained on a plant-specific basis in accordance with the requirements of IOCFR50, Appendix B.

The projection technique has been used successfully for many years at Duke Energy's McGuire and Catawba Nuclear Stations to predict outage maintenance scope. As an alternate mass deternination technique, it represents the most precise technology outside the manual lifting method, but requires a significant amount of accurate historical ice mass data in order to generate projections. This technique entails observing the mass of individual ice baskets over a period of time (many cycles), and, through successive end-of-cycle weighings of the basket, determining the total ice loss that occurs over the period.

From this information, a sublimation rate is calculated, and when a projection of the basket's mass is required (i.e., if the basket were to become stuck), the sublimation is extrapolated to the desired date (e.g.,

the end of the current cycle) from the last known lifted mass. This technique requires a data validity criterion (described later), which limits the use of the most historically distant data in projecting a current basket's mass and also linits the number of times a given basket's mass can be projected successively before a lifted mass on the basket is required. It also requires that the uncertainty calculation be updated with newly obtained data after each outage to reflect the most recent sublimation trends in the ice bed.

The end-of-cycle mass data, being obtained by manual lifting, limits the technique's capabilities as an as-found surveillance tool where a large number of stuck baskets have existed for some time. In this case, Licensees have the option of getting these stuck ice baskets free (e.g., via labor-intensive means) and keeping them free for several successive cycles to refresh the sublimation trend, or not using the projection technique. In the latter case another mass determination method would be required.

Sequoyah Nuclear Plant has developed and employed a procedure for performing a visual inspection of the ice basket column in order to determine its mass. This method involves a camera inspection over the length of the ice basket while estimating the amount of ice mass missing from the column in the form of linear gaps, shaped voids, and annular "shrnk-back" from the ice basket mesh. The mass of missing ice from the various voids is totaled and the result subtracted from the known mass of a full basket, providing an estimate of the actual ice mass in the basket. This technique has been utilized successfully over several outages at Sequoyah as a scoping technique for outage maintenance, and is used in areas of the ice bed where stuck baskets are typically found (e.g., Radial Zone A). Experience with the visual estimation technique has shown that a reasonable assessment of ice basket mass can be made; some ice baskets found stuck and their mass estimated using this technique have been subsequently freed and manually lifted, giving a direct comparison for analytical purposes. In addition, ice baskets recently lifted have been visually estimated to provide additional data. As with the mass projection method described previously, this method of mass estimation requires a validity criterion requiring comparative determination of ice mass using the lifting method in order to maintain a quantifiable uncertainty. As the most subjective of the three methods defined so far, visual estimation of basket mass, used on a large scale, will likely require Licensees utilizing it to maintain more ice in their ice bed due to the greater uncertainty associated with this method.

In order to assess the viability of other alternate mass determination methods, TVA commissioned a study through an independent consulting company to investigate new technologies for non-intrusive inspection of the ice colunm profile in the ice baskets. The goal of the study was to find a technology that would provide an estimation of the volume of the column and therefore the mass of the ice in the column. Based TOPICAL REPORT ICUG-001, Revision 2 II-2 June 2003

on the results of the investigation it was concluded that the use of ultrasonic measurement techniques was best suited to this application, with laser technology also recommended. In both cases, inspection of the ice column requires a scanning device to be sent along the length and periphery of the ice column. The delivery system and hardware pose a significant challenge in developing this technology. TVA elected to proceed with the development of the ultrasonic measurement technique. A prototype system was assembled and given a proof-of-concept test at the Watts Bar Nuclear Plant; the test concluded that the prototype system was able to profile the surface of the ice in a basket and that the data could be recorded for future analysis. However, challenges identified with the delivery mechanism for the ultrasonic probe and the retrieval of the data collected from the scan need to be resolved before this technique can be successfully utilized as an alternate mass determiination method.

For any of the alternate mass determination methods described herein (or for methods subsequently developed), quantitative validation of the technique will be maintained on a plant-specific basis in documents developed under the auspices of IOCFRSO, Appendix B and 10CFR5O.59. Quantitative validation determines the specific uncertainty of the methodology, and identifies the associated measures of relative standing (e.g., systematic bias and random error). Individual ice basket masses deternined using an alternate technique are quantified using a standard method agreed upon by the industry, which facilitates the determining of total ice bed mass as described in the Statistical Sampling Plan (Section E).

In addition, this method provides for showing the predictability and repeatability of the techniques, as well as documenting the plant-specific data used to develop them.

Standards: Ice Basket Mass Deternination Uncertaintv This section considers the error and uncertainty in measurements and calculations performed while determining the mass of individual ice baskets, and provides a model by which the uncertainties inherent in different methodologies for determining individual ice basket mass can be defined.

As discussed previously, there are three documented methods used for determining the mass of an ice basket:

1. Direct lifting of the basket with a lifting rig utilizing a calibrated load cell,

2. Projection of the basket's expected mass from historical data and calculated sublimation rates (determined using mass data obtained by load cell), and

3. Visual approximation of the basket's mass made from a full-length inspection of the ice basket using a video camera.

All of these methods rely, to some degree, on basket mass data obtained through the use of a load cell device. Methods 2) and 3) were uniquely developed to facilitate determining the mass of baskets that cannot be directly lifted due to obstruction or ice build-up around the basket's periphery, a situation that occasionally occurs in some baskets that were initially free to lift. For each of these methods, the uncertainty in the mass determinations must be defined prior to their use in satisfying technical specification surveillance total ice bed mass requirements. The application of these individual uncertainties to the appropriate surveillance requirements is discussed in detail in Section EII.

Concepts regarding uncertainty

> Every measurement has an uncertainty associated with it, unless it is an exact, counted integer.

> Uncertainty arises from errors introduced into the neasurement process, and errors arise from both systematic bias and precision-related issues.

TOPICAL REPORT ICUG-001, Revision 2 II-3 June 2003

> Every calculated result also has an uncertainty, related to the uncertainty in the measured data used to calculate it.

> The numerical value of a +/- uncertainty value provides the range of the result. For example, an ice basket mass identified as 1,465 + 15 lb means that there is some degree of confidence that the true value falls between 1,450 lb and 1,480 lb.

Error The error in a measurement is the difference between the measurement and the actual or true value of the quantity observed. Since the true value is often not known, the exact error is also unknown.

Errors are typically divided into two types: systematic and random. Systematic errors (also known as bias) can result from fundamental flaws in the equipment, the performer, or in the use of the equipment.

For example, a load cell may always read 5 lb light due to being zeroed incorrectly. Similarly, a member of a weighing crew may consistently overestimate a visual estimation of ice mass in a basket. This type of error, if it cannot be calibrated out (as might be the case with a mass measurement made by visual estimate or sublimation-projection rather than an instrument), must be identified and included in any measurement uncertainty.

Random errors vary in a completely non-reproducible way from measurement to measurement. However, random errors can be treated statistically, making it possible to relate the precision of a calculated result to the precision with which each of the measured variables (such as individual basket mass) is known.

Random error is typically estimated by the standard deviation (denoted by v) of a group of repeated measurements centered about a mean.

To assist in recognizing types of error, consider the task of measuring the distance between two parallel vertical lines drawn on a piece of paper. Typical technique would be to use a ruler, aligning one end of the ruler with one line, and reading off the distance to the next. Random errors might arise from two sources:

1. Instrumental error (e.g., ruler calibration, spacing and size of the ruler's graduations), and

2. Uncertainties in the lines (e.g., thickness of lines, temperature and humidity effects on the paper).

A third source of error also exists, however, related to how any measuring device is used. In this case, the error might be made aligning one end of the ruler with one line. The ruler should be placed on the first line randomly (but as perpendicular to the lines as possible), the position of each line on the ruler noted, and the two readings then subtracted. This should be repeated several times, and the differences averaged.

This process eliminates the systematic bias (i.e., the error that occurs in each measurement as a result of the measuring process itself) that aligning one end with one line introduces.

A final type of error must be mentioned as well: erratic error (or a blunder). These errors are the result of a significant mistake in the procedure, either by the performer or by the instrument. An example would be misreading the numbers on a load cell read-out and entering incorrect information into the basket mass history database. Another example would be unnoticed excessive friction between the sides of a basket and the lattice steel while using a lifting rig with a load cell. The load cell itself might produce a blunder if a poor electrical connection causes the display to read an occasional incorrect value. If the mistake is caught at the time of the procedure, the result should be discounted and the measurement repeated correctly. If the mistake is missed, blunders can be difficult to trace and can give rise to much larger error than random errors. If a result differs widely from a known (or expected) value or has low accuracy, a blunder may be the cause. If a result differs widely from the results of other performed measurements, a blunder may also be to blame. The best way to detect blunders is to repeat all measurements at least once TOPICAL REPORT ICUG-001, Revision 2 114 June 2003

and compare to known or expected (benchmark) values, if available. Blunders can also be avoided through careful application of procedural controls for the measurement process.

Precision of Instrument Readings and Raw Data The first step in uncertainty determination for a process or calculation is to estimate the precision of the raw data used in the calculation. Consider three mass determinations made on the same ice basket using a load cell w/digital read-out as follows (all are basket + ice):

1st weighing = 1,652.1 lb 2nd weighing = 1,654.3 lb 3rd weighing = 1,656.2 lb The average, or mean, mass of the ice basket is therefore:

M.

=

1,652.1 + 1,654.3 + 1,656.2 = 1,654.2 lb 3

In this example, the precision or reproducibility of the measurement is t 2 lb. All three measurements can be included in the statement that the basket has a mass of 1,654 +/- 2 lb. The load cell read-out in this example allows direct reading to one decimal place, and since the precision is roughly 2 lb, the load cell has the necessary sensitivity for this measurement.

At this point, there is little knowledge of the accuracy of the mean basket mass, 1,654 +/- 2 lb. The accuracy of the weighing process depends on the accuracy of the internal strain gauges in the load cell as well as on other instrumental calibration factors. The manufacturer's stated accuracy for this load cell is +/-

0.3% of full scale, which for a 0-5000 lb scale is about 4 15 lb. This is verified every time the load cell is calibated, and often the accuracy achieved is better than that stated by the manufacturer. Since the measurements are also being made well within the full scale range of the load cell, it can be expected that a correctly calibrated instrument, used according to procedure, will give an accurate result. Therefore, in this example the precision displayed by the measurements is well within the expected calibrated uncertainty of the load cell. The high precision of the three measurements (+/- 2 lb) indicates that a blunder has not been made, and in addition shows a reduced likelihood of significant systematic bias.

Quantifying Measurement Uncertainty For simplicity of presentation a single number (some combination of systematic bias and random error) is needed to express a reasonable limit for uncertainty. The single number must have a simple interpretation (the largest error reasonably expected) and be useful without complex explanation. It is not feasible to define a single rigorous statistic, because systematic bias is an upper limit based on judgment and experience with a particular process which has generally unknown characteristics. The function, then, must be a hybrid combination of an unknown quantity (systematic bias) and a statistic (random error).

At this point, the adoption of a standard for defining basic uncertainty is appropriate. The standard most frequently used is the bias limit plus a multiple of the random error. This method is recommended by the National Bureau of Standards and has been widely used in many industries. Utilizing this standard, uncertainty may be centered about an individual measurement and defined as:

U= : [B + (t9s 0)]

Where B is the systematic bias limit, a is the random error, and t95 is the 9 5d percentile point for the two-sided Student's t"' distribution. The value of t 5 is a function of the degrees offreedom (or sample size) used in calculating r. For small sample groups, t5 will be large, and for larger sample groups, t95 will be smaller, approaching 1.96 as a lower limit (for sample groups > 500). The use of tgs arbitrarily inflates the TOPICAL REPORT ICUG-01, Revision 2 11-5 June 2003

9-uncertainty U to reduce the risk of underestimating a when a small sample is used to calculate it. In essence, the 9 5h percentile points in a two-sided distribution capture 95% of the population of measurements centered about the mean value.

In view of the above discussion, clarification is needed regarding the proper quantification of individual ice basket mass determination uncertainty values that are to be used in satisfying legal technical specification surveillance requirements. Because of the nature of the technical specification limits (i.e., a minimum allowable ice mass for legal operability), it is industry convention to use a one-sided interval for uncertainty, to ensure only conservative (i.e., lower) values of basket mass are included in the calculations. For example, an ice basket mass of 1,642 +/- 15 lb would propagate to the surveillance requirements as 1,627 lb (in actual practice the tare weight of the ice basket would also be removed in order to reflect the ice mass available for pressure mitigation alone). In the case of a biased uncertainty (where B 0), a non-conservative bias component (i.e., one that raises the apparent mass determined using that process) would not be included in the uncertainty, while a conservative bias component (i.e.,

one that lowers the apparent mass determined using that process) would be included.

Because of the one-sided convention, the quantification of uncertainty for ice mass determinations will take the form:

U = - [3 + (tg a)]

The value of tg5 will also change to the value corresponding to a one-sided test, which approaches 1.645 as a lower limit (for sample sizes > 1000). Standard tables for the critical values of t for one-and two-sided tests and for various sample sizes are available in Reference 25, or in any statistics text.

For the load cell (an instrument calibrated in a standards laboratory prior to being used), the stated measurement uncertainty should contain no systematic bias components. Repeating individual basket mass measurements in the field will further reduce the risk of inserting procedure-related systematic bias into the process. Therefore, in the three-basket mass determination example described previously, the basket mass would be quantified as 1,642

• 15 lb (or whatever the calibrated accuracy of the load cell turned out to be).

For more subjective basket mass determination methods other than direct lifting, such as the mass sublimation projection and visual estimation processes, it is imperative that uncertainty components (systematic bias, random error, and degrees of freedom) be defined and available in supporting documentation. These three components will be required to: 1) substantiate and explain the uncertainty value, and 2) provide a sound technical basis for improved measurements. In addition, the individual uncertainty components are applied independently to the required 95% confidence interval calculation of ice mass (as described in Section III) in the technical specification surveillance requirements, and documenting them in this manner facilitates that usage.

Historical Data Validity - Alternate Ice Mass Deternination Methods The two currently defined alternate techniques for determining individual ice basket mass are:

1. Projection of a basket's future mass via a sublimation trend calculated using accumulated data from historical load-cell determined values for that basket, and

2. Visually estimating a basket's mass by accounting for the voids present in the sublimated basket, and subtracting the associated "missing mass" from a pre-defined full basket mass value.

Since neither of these techniques directly involves a measuring instrument, "calibration" occurs through data analysis and refinement of the techniques. Applying an uncertainty value to either of these TOPICAL REPORT ICUG-001, Revision 2 II-6 June 2003

techniques using outdated historical data is not an acceptable way to verify that the procedure is a valid alternate mass determination process. Therefore, the following is the industry standard for refreshing the historical data used to validate these two methodologies:

Table 2-1. Alternate Mass Determination Technique Data Refreshment Criteria Mass data used for uncertainty calculations must derive from:

3 of the last 6 operating cycles, or 2 out of the last 3 operating cycles.

For the mass sublimation projection technique, this represents 1,500 to 3,000 days of current sublimation data or about 1,000 days of the most recent data for the associated basket to determine average sublimation rates. For the visual estimation method, this criterion links the data used in the analyzed distribution to the most recent experience with the technique, and also limits the data obtained for uncertainty analysis to ice baskets that can be repeatedly lifted.

Another important aspect of data validity involves the qualification of personnel trained to perform alternate mass determination techniques. In the case of mass sublimation projection, extrapolation of a point from historical data is much less subjective than accounting for visually estimated voids in an ice basket. For this reason, the latter methodology would be expected to require a rigorous training and testing protocol to ensure that accumulated data used to identify and ultimately refine process uncertainty has the highest practical quality. An efficient way of handling this is through a standardized "test" that displays the most commonly observed void characteristics in a sublimated ice basket, and depicts those voids in actual ice bed conditions (e.g., low lighting, less than ideal camera focus, space limitations).

Video tapes, in situ estimations during scheduled outages, and practice with mock-ups are all appropriate for establishing this quality. In addition, a visual acuity test would be required to ascertain the ability of the performer to evaluate these voids in the ice bed, and qualification of the equipment provided to perform the procedure (i.e., camera, lighting) must be made.

By defining the historical data validity standard in this way, plants can ensure consistent documentation and application of the uncertainty values used in satisfying the legal technical specification surveillance requirements. This standard is applied through incorporation in plant-specific procedures that are maintained in accordance with IOCFR50, Appendix B.

Examples The following two examples illustrate the statistical analysis of historical data for both the sublimation projection and visual estimation alternate ice basket mass determination techniques. The data analyses are performed to identify the uncertainty components for each method, and provide an outline by which plant documentation can be generated that conforms to the standard model presented herein. In these examples, the actual data sets (i.e., the individual basket mass measurements) are not shown due to their size, but represent typical industry data nonetheless. It can be assumed that all data were collected/calculated via established procedures by personnel qualified to perfonn them.

TOPICAL REPORT ICUG-001, Revision 2 II-7 June 2003

Mass Sublimation Projecion Using Historical Data There are several different ways to determine the sublimation rate of an individual basket using historical data. The method used primarily by the industry involves reviewing up to six previous operating cycles' worth of data for a basket (in accordance with the criteria established previously) and determining, from successive load cell mass determinations on the basket, the total quantity of ice loss that has occurred over the period. The result is a linear depiction of sublimation, with the rate of sublimation represented by the slope of the line. The unbiased uncertainty (e.g., + 15 lb) involved in the individual measurements of mass made over this period using the load cell is typically a constant and therefore does not change this slope, but does affect the location of the line. If the next point along the line is to be projected (extrapolated using the slope) rather than identified via load cell, an uncertainty is inserted because the slope is an approximation of sublimation based on many varying parameters, such as operating cycle transients, air handler unit performance, and even seasonal factors. At the outcome of this projection, the historical load cell uncertainty is added to the projection uncertainty, as it becomes a "known" form of systematic bias.

For this example, mass data for 1,024 ice baskets were collected over six consecutive outages in a particular ice condenser. At the end of the last operating cycle, these baskets were weighed with the load cell and their mass also individually projected using the sublimation rate determined by this historical data. The two values for basket mass were then compared and the differences between them categorized into "ranges" of mass difference as follows:

Table 2-2. Projection Method Example Data

~(Projected Mass) - (Lifted Mass) Results Range Frequency (lb)

(# baskets in range)

-100+

2

-99 to-71 3

-70 to -51 6

-50 to -41 18

-40 to -31 62

-30 to -16 175

-15 to 15 553 16to30 119 31 to 40 42 41 to 50 12 51 to 70 24 71 to 100 5

100+

3 Total 1,024 Ranges were chosen based on an inspection of the data spread and on those groupings that would facilitate insight into comparison with load cell accuracy.

From this table of results, it can be seen that a fairly symmetric distribution of points exists, centered about the range -15 to + 15 lb. Note also that a positive difference (> 0 lb) is representative of a non-conservative projection of mass, that is, the projection was higher (indicated more mass) than the benchmarked load cell data point, which is considered more accurate. In terms of uncertainty, however, this is conservative, since it increases the error band. Graphically, this data can be represented as:

TOPICAL REPORT ICUG001, Revision 2 11-8 June 2003

Figure 2-1. Projection Method Example Chart In order to determine the expected uncertainty to be included for baskets using this technique based on the collected data, recall from the previous discussion that the systematic bias, random error, and the degrees offreedom (sample size) must be identified.

The systematic bias and random error can be determined from the comparison data by calculating the mean difference and its standard deviation. Performing these statistics operations (the actual 1,024 compared data points are not presented here for clarity) yields:

Mean Difference = -1.7 lb = -2 lb Standard Deviation = = 24.5 lb = 25 lb "Rounding" (conservative measure based on knowledge of the data and associated significant figures) is used here since these values were computed from individual basket mass measurements that have an explicit uncertainty of k 15 lb (the calibrated, unbiased load cell accuracy). The implicit accuracy of the load cell measurements is to three significant figures (e.g., 1,642 + 15 lb would be written 1,640 lb). As such, recording these two statistics to +/- 0.1 Ib, while technically allowed, is not practical.

For the calculation of the systematic bias, B, two values will need to be applied: the calculated mean difference of the data set and the offset associated with the accuracy of the benchmark value. If the mean difference is negative (i.e., non-conservative), then it is set to zero, and the benchmark value (load cell error) assumed for the value of B. If the mean difference is positive (i.e., conservative for uncertainty),

then the load cell error and mean difference are added together to determine the systematic bias component.

TOPICAL REPORT ICUG-001, Revision 2 June 2003

-9

The sample size in this case is 1,024 baskets, which corresponds to the lowest one-sided test value for tgs (the 95' percentile point for infinite degrees of freedom). So, from the tabulated values in Reference 3:

tgs = 1.645 From this analytical observation of the collected data points, the uncertainty for this mass projection technique can be calculated as:

U = - [B + (t95 X )]

U = - [B + (1.645 x 25)]

Since the mean difference is negative in this case, which is non-conservative in terms of uncertainty, set B

= 15 lb (the propagated load cell error), and:

U = - [15 + (1.645 x 25)] = - [15 + 41]

E U-56lb I

This is an example of the quantified uncertainty that would be included when utilizing projection of ice basket mass. The minus sign indicates that, for analytical applications regarding compliance with the technical specifications, the mass is always reduced.

Visual Estimation of Ice Basket Mass Estimating the mass of an individual basket via visual inspection of the voids in the ice contained therein is a somewhat more subjective procedure than sublimation projection. Along with the previously descnbed variables, the visual estimation technique contains other sources of error such as lighting, camera resolution, blockage of view due to frost build-up on the basket surface, and the procedural convention of assuming voids are symmetric, among others. It should be expected, then, that this technique will yield uncertainties that are larger, due to the increased likelihood of systematic bias and a wider distribution of data around the mean (random error). In addition, the mass of an ice basket is determined by subtracting the mass represented by the inspected voids from a "full" basket mass, which introduces further chance for error by requiring an assumed constant density of compacted flaked ice (to determine mass from volume measurements).

It is beneficial to accumulate as much individual basket mass data as possible using a consistent, well-written visual estimation procedure performed by personnel qualified to a standard test, and to obtain load cell data on these same baskets as a correlation. Having established that, and verifying that the data being analyzed for uncertainty determination conforms to the standard set for validity discussed previously, the statistical approach can be used to isolate the required measures of relative standing of the data set to determine the uncertainty as was done for the mass sublimation projection technique.

For this example, 238 individual basket mass data points were collected over two of the last three cycles for a particular ice condenser. Each of these baskets was visually estimated by established procedure and had a corresponding mass determined via load cell (with an unbiased uncertainty of 4 15 lb). Using the same style of presentation as the projected mass example earlier, the following table of compared values was generated:

TOPICAL REPORT ICUG-001, Revision 2 II-10 June 2003

Table 2-3. Visual Estimation Method Example Data (Visfll Estima;ted Mass - (Lifted Mass) Results Range Frequency (lb)

(# baskets in range)

-400 to -499 2

-350 to -399 1

-300 to -349 1

-250 to -299 8

-200 to -249 6

-150 to -199 9

-100 to -149 15

-50 to -99 18 0 to 49 21

+1 to +50 28

+51 to +100 28

+101 to +150 29

+151 to +200 21

+201 to +250 23

+251 to +300 15

+301 to +350 7

+351 to +400 2

+401 to +499 4

Total 238 Again, it can be seen that a fairly symmetric distribution exists for this data, though it appears to be biased non-conservatively for the basket mass determinations (i.e., it tends to show more ice mass than is actually present). This indicates that a positive bias will add to the uncertainty, unlike in the previous example. Graphically depicted, the comparative results for the visual estimation technique look like this:

Figure 2-2. Visual Estimation Method Example Chart TOPICAL REPORT ICUG-00l, Revision 2 June 2003 11-11

From the comparison data (again not presented here for clarity), the systematic bias, random error and degrees of freedom are determined:

Mean Difference = 57.7 lb = + 8 lb Load cell (correlation) uncertainty = :k 15 lb Standard Deviation = a = 166.7 lb = 167 lb Degrees of freedom (sample size) = 238 Note that the mean difference and random error values are again rounded conservatively.

For a sample size of 238, the one-sided distribution 95h percentile point is defined by a ts value equal to 1.65. Therefore:

U = - [B + (t, xr)]

U = -[B + (1.65 x 167)]= -[(58 + 15) + 276]= -[73 + 276]

lU -349 lb l1 In this case, the uncertainty is a true combination of bias (73 lb) and random error (276 lb). Again, the minus sign indicates the conservative convention for the one-sided interval; however, when applying this uncertainty to the surveillance requirement calculations for estimating total ice bed mass, the bias and random error components are accommodated separately.

Example Summary These examples illustrate a statistical method of identifying the uncertainty due to systematic bias and random errors in the determination of individual ice basket mass. As expected, the uncertainty value for the visual estimation mass determination technique in the example is significantly higher: six times that predicted by the sublimation projection technique example, and over twenty times that determined by a typical load cell measurement made by direct lifting. This spread in the uncertainty values properly reflects the inherent subjective nature of the altemate mass determination techniques. In order to reduce the uncertainty of these methods, there are several approaches that can be taken:

1. Minimize the t value by keeping the comparative sample size large. This requires the accumulation of large quantities of basket mass data using the alternate techniques, an effort that will provide experience with the techniques as well as recent, valid information in accordance with the standard.

2. Refine the subjective measurement techniques, thereby eliminating sources of bias and random error that are introduced. Experience through outage data collection as well as through practice on mock-ups all provide opportunities for process refinement. Also, improvement in the tooling used (such as cameras and lighting) will be beneficial.

3. Improve the accuracy of the benchmark by calibrating the load cell to a higher standard. The load cells used in the industry can generally be calibrated better than the manufacturer's stated accuracy.

4. Improve the consistency of the input data (i.e., the individual basket mass data) for the more subjective measurement techniques. This can be accomplished by qualifying each performer of TOPICAL REPORT ICUG-001, Revision 2 II-12 June 2003

the visual estimation technique to a rigorous test standard, and by providing a well-written estimation procedure.

Conclusions The manual lifting technique provides the fastest and most accurate method of determining ice mass. For baskets that are stuck, there are two altemate ice mass determination methods that have industry standards developed. These are:

1. Projection of ice basket mass using software and historical data, and

2. Visual inspection of the ice basket.

In general, the software projection technique provides the most accurate altemate mass determination method, but it requires several sets of quality data in order to provide valid results. Further, its projections for a given ice basket are invalidated if the subject basket becomes stuck (unliftable) and is serviced anyway, thereby creating an unsubstantiated change in the mass of ice in the basket. The accuracy and consistency of software projections is dependent upon population and replenishment of the database with recent ice mass data (as required by the data validity standard) obtained via manual lifting.

The visual inspection technique offers another method of ice basket mass determination, useful due to its ability to estimate the mass of stuck baskets, most notably during an as-found surveillance. Like the software projection method, the accuracy of this technique is a function of the amount of data that has been collected, but it has other influences as well, such as procedural experience and basket surface ice.

Based on the subjective nature of the estimation process involved and as depicted by the examples, the visual inspection method typically has a lower accuracy than the ICEMAN'h projection. However, once the uncertainty in the methodology has been defined in accordance with the industry standard, it can be utilized on an ice basket to estimate its mass, and represents an acceptable alternative approach to assessing ice basket mass for the purposes of the surveillance. As discussed in Section I, the larger uncertainty involved with this methodology may necessitate larger initial statistical sample groups in affected Radial Zones in order to adequately assess the minimum mass requirement (i.e., reduce the statistical penalty associated with taking a smaller sample), and will likely also require the Licensee to maintain more ice in these Radial Zones to account for the technique's lower accuracy.

The hierarchy of techniques, as described in this Section and outlined in Figure 0-1, is as follows:

1. Upon randomly selecting an ice basket for the surveillance, attempt to lift the basket using a lifting rig and an attached load cell device. If this is unsuccessful (i.e., if the basket is stuck or otherwise obstructed), Licensees have the choice of an alternate mass determination technique (if their plant procedures document one), or selecting an alternate basket for the surveillance subject to the given limitations (discussed in Section E).

2. If an alternate mass determination technique is available and utilized, the documented uncertainty is applied to the measurement in accordance with the established uncertainty standard, and this result carried through to the statistical sampling plan (outlined in Section III).

3. If the mass of the randomly selected basket for the surveillance cannot be ascertained by any available means, an alternate selection must be made subject to the given limitations (discussed in Section I).

As with all subjective techniques, proper training of personnel, well-written procedures, and proper qualification of associated equipment are required to properly document the alternate mass determination methodologies and reduce the uncertainties associated with them. The plant-specific documentation of mass determination technique uncertainty values will include the uncertainty calculations and associated valid data from that plant in accordance with the standard established herein, as well as supporting procedures and training/equipment qualifications in accordance with OCFR50, Appendix B.

TOPICAL REPORT ICUG-001, Revision 2 11-13 June 2003

III Ice Mass Statistical Sampling Plan PumoselScope The purpose of this Section is to provide the basis for the statistical sampling plan that will be used to demonstrate that adequate ice mass is maintained in the ice bed troughout the operating cycle. The statistical sampling plan, as developed herein, addresses the sample size, statistical approach, the effect of mass determination uncertainty, and the selection of alternate sample baskets.

Ice Mass Statistical Strateq' The objective is to estimate the total mass of all of the ice baskets in the ice bed based on a sample of those baskets. Since the standard deviation of the true individual masses of the ice baskets is not known and the number of samples taken is relatively small, the statistical "Student's t-test" applies (Section 3.5.2 of Reference 11, and Chapter 8 of Reference 12). The Student's t-test is used to establish how much the actual mean ice basket mass () could be less than the mean ice basket mass observed in the sample (X). A confidence level (1-a) is associated with this lower bound (- 1J. For the mean basket mass, a confidence level of 95% has been selected. Using the t-test, it can be established that there is 95% confidence that the actual mean ice basket mass is greater than some value,

,. Figure 3-1 provides an illustration of the Student's t-test.

Figure 3-1. Illustration of Student's t-Test Ice Basket MassA (lb)

Pua tl-a r Mean Mass Per Basket in Sample Population Mean Mass Per Basket in Entire Population, with -a Confidence TOPICAL REPORT ICUG-001, Revision 2 June 2003 II-1

Using the "Student's t-test," with l-a confidence, the mean individual ice basket mass is at least:

I jt nt

]xCF]

(Equation 3.1)

Where:

tl-a = Mean mass per basket of the total population with 1-a confidence X = Mean mass per basket of the sample group of size n ti_a = critical value of t that is a function of the confidence interval -a and the degrees of freedom in the sample (n-1). This value can be obtained from References 9, 11, and 12.

1-a = confidence interval = the fraction of the estimated intervals (calculated from all possible sample populations and using Equation 3.1) that can be expected to include the true or actual average of the total population (Section 3.5, Reference 11)

X(X; X)2 s = standard deviation of the sample group =

n-i X; = mass of i-th sample (corrected for systematic bias)

CF = (N n)= Correction factor for a finite population (References 8, 11, and 13) n = total number of baskets in sample N =total number of baskets in the population represented by the sample The second term in Equation 3.1 represents the error of the mean. This error represents the fact that the mean mass per ice basket calculated from a sample group may differ from the actual mean mass of the parent population. To obtain the total mass of the ice bed with 95% confidence, the individual mean ice basket mass determined from the sample group, pI-,, is multiplied by the total number of baskets in the parent population.

Equation 3.1 is the standard approach, used for analyzing a distribution of mass data that does not require addressing the uncertainty in individual measurements. The use of Equation 3.1 would require measurement uncertainty to be addressed generically elsewhere, such as in the surveillance limit. In cases where the accuracy of the mass determination methodology used is low or varies, it must be accounted for in the calculation of the error of the mean. This would be the case when methods other than direct lifting using a scale or load cell are used in determining individual ice basket mass. As such, the following equation derived from the discussion in Section 8.3.1.1 of Reference 11 will be used to calculate the lower bound of the mean individual ice basket mass:

TOPICAL REPORT ICUG-001, Revision 2 II-2 June 2003

2

+/-npi 1 xCF j

(Equation 3.2)

Where:

j = number of mass determination methods used n = number of baskets within the sample whose mass is determined by method i ai = the random error of the mass determination method i With this approach of accounting for the random error of the mass determination method (i.e., the variation of the measurement), any systematic bias (an error which remains constant over replicate measurements; see Table 14.1, Reference 11) of the mass determination method is applied to the individual basket mass values prior to calculating the mean basket mass and standard deviation of the sample group. In other words, the mass of a given ice basket is adjusted for the systematic bias of the mass determination method used, before the mass value is used as an input to Equation 3.2. The random error of the mass determination method (as ), should be equivalent to one standard deviation.

In this equation, the variation of the process (as compared to the variation of the measurement) is represented by the observed sample standard deviation, s. It is important to note that this will insert some conservatism because the observed sample standard deviation will include effects of the measurement variation, which will, to some degree, be expected to increase the standard deviation.

For the purposes of the Ice Mass Technical Specification supported by this topical report, Equation 3.2 will be the assessment method.

Sample Size In using Equation 3.2, the sample size n considers the following:

1. The "Student's t-test" is based on a normal distribution. However, Reference 9 indicates that unless the number of samples is less than about ten, the assumption that the subject population follows a normal distribution will not significantly affect the validity of the results obtained, even if a normal distribution is not present.

2. The desired interval, or in this case the lower bound of the mean basket mass, will affect the sample size since typically the more samples taken, the narrower the interval tends to become.

3. The sample size is generally selected independent of the population size, if the population size is sufficiently large. However, the population may be stratified or broken into groups that are expected to have similar characteristics (e.g., mean and standard deviation). If this approach is used, the sample size is defined in terms of the stratified population group (such as n samples out of all ice baskets in a defned Radial Zone as a fraction of the 1,944 baskets in the entire ice bed, as discussed in Section 1).

While it is not considered necessary, the normality of a sample may be verified by using the methodology given in Reference 10. Random, statistically representative samples will generally result in fairly normal distributions. However, as mentioned previously, even if the sample is not normal, the "Student's t-test" will provide valid results as long as a sufficient number of samples are taken.

TOPICAL REPORT ICUG-001, Revision 2 111-3 June 2003

Figure 3-2 provides an illustration of the relationship between number of samples and the error of the mean, assuming for the purpose of the example that there is no error in the measurement technique, and the standard deviation of the sample group is 100 pounds (which was selected considering typical standard deviations seen in ice condenser basket populations). In reality, there would be uncertainty in the measurement technique, and the curve in Figure 3-2 would be shifted upward. The figure demonstrates that once the number of samples is increased beyond approximately 30, the reduction in the error of the mean levels out. However, further reduction as a result of taking more samples may still be beneficial.

Figure 3-2. Effect of Sample Size on the Error of the Mean (assume s = 100 lb and no measurement technique error)

I I

IIs A

iwJ 160-140 --

i 120 l_

20-

+_

4-

__I_I_

w~

~~~

I 40 0

20 30 40 60 80 100 Nwnber of Sampbs 120 140 160 180 200 Experience has shown that a representative sample, such as the one utilized in the original Ice Mass Technical Specification and described in Section I, could provide more useful information than a blind random sample. Therefore, the overall sample size may be driven more by obtaining a representative sample than by meeting minimum sample size requirements. For example, a representative sample may be generated by taling the same number of samples per row in the ice bed. However, when performing stratified sampling, it is noted that minimum sample size criteria must be met when the focus is on a sub-population of the ice bed.

The initial sample group can be expanded as necessary (such as when the calculated total mean mass of the ice bed is below the minimum required total mean ice mass); however, the initial sample population must be retained and the additional samples added to build the sample group as follows:

n, = initial sample group nb = expanded sample group = n.+nc nC = additional samples taken Note that the initial sample group is not discarded; rather, it becomes an element of the expanded sample group. This concept is based on Stein's Procedure in Chapter 8 of Reference 12.

TOPICAL REPORT ICUG-001, Revision 2 June 2003 II1-4

Stratified Samplina Since, as shown in Section I, there is appreciable radial mass variation between some individual baskets in the ice bed population, stratified sampling is beneficial as it minimizes the risk that a small random sample will contain a disproportionate number of a minority group. Stratified sampling involves dividing the total population into groups of items that are expected to have similar characteristics (particularly the characteristic of interest), such as, in the case of the ice bed, mean basket mass and sublimation rates. As discussed in Section I, Radial Zones may be defined in the ice bed as groups of rows such that Zone A contains rows 7, 8, and 9; Zone B contains rows 4, 5, and 6, and Zone C contains rows 1, 2, and 3 (see Figures 3-3 and A-1) where each Radial Zone may even have different minimum design basis mass requirements. The total mass of ice in the ice bed with 95% confidence is obtained by summing the total masses of each stratified sub-population (or Radial Zone). The total mass of each Radial Zone is determined with 95% confidence by multiplying the mean calculated individual basket mass for the sample in that Zone by the total number of baskets in that Zone.

Figure 3-3. Illustrative Plan View of Ice Bed, Showing Three Radial Zone Groupings of Ice Baskets (648 baskets each) 10 9

8 7

6 pp;i 12 13 22 23 2

5 4

3 2

• '-~~ZoneB B

ioiwe C TOPICAL REPORT ICUG-001, Revision 2 June 2003 III-5 Lo " 7,

Assurance that the ice in the ice bed is both evenly distributed and the total ice mass meets a specified limit is provided by stratified sampling, since all regions (or stratified sub-populations of the ice bed) are equally represented and evaluated. Further, the baskets within a Radial Zone would have a fairly normal distribution, to which the sampling plan can be applied.

Examination of recent historical data from various ice condenser plants (reference Section 1) indicates that certain radial rows consistently sublimate at markedly different rates than others. The innermost crane wall rows sublimate at a higher rate than the outer rows as a function of their proximity to heat sources (Figure 34). Depending on ice bed and containment temperatures (and other characteristics unique to each plant), general radial sublimation rates will vary from plant to plant, but the overall trend is the same. Therefore, stratified sampling is applied to the generic case by grouping these Radial zones based on industry-wide historical sublimation and ice mass data.

Figure 3-4. Plan View of Containment Building, Showing Proximity of Steam Generator and Pressurizer Compartments to Ice Condenser Bays TOPICAL REPORT ICUG-001. Revision 2 I-6 June 2003

It is also noted that when random sampling without replacement is used (where each basket in the sample can appear only once, with each basket in the total population having the same probability of being selected), the sample will generally result in the various regions of the ice bed being well represented.

The azimuthal (as opposed to radial) distribution of ice (see Figures 3-3 and 3-4) does not need to be verified via stratification if the overall azimuthal sublimation rate of the ice bed is not expected to vary significantly. As described in Section L historical industry and plant-specific data show that azimuthal variances would not preclude a random sample from being representative of the ice bed.

Altemate Mass Determination Methods To show compliance with the ice mass technical specification surveillance requirements, the mass of the individual sample ice baskets is typically determined by lifting the basket with a lifting rig and an attached scale or load cell. The accuracy of the scale has been treated conservatively in the past as a systematic bias and accounted for in as-left (pre-maintenance) ice mass surveillance requirement limits.

However, some baskets have a tendency to become stuck (i.e., frozen in place) as a result of surface ice accumulation, and cannot be physically lifted. To address this in the sampling plan, alternate mass determination methods will be utilized. Alternate mass determination methods are expected to have a lower accuracy than the lifting rig method, but will provide a reasonable assessment of ice mass when a sample selection is initially found to be stuck. As described in Section II, there are three primary methods designed by the industry to deternine individual ice basket mass: direct lifting using a scale or load cell, software projection of the ice basket mass using basket mass histories and sublimation rates, and a visual inspection/estimation process. The uncertainty of a given method is a combination of the method's systematic bias and random error. As discussed previously, the individual observed ice basket masses are adjusted for systematic bias before the mass value is used as an input to Equations 3.2. Approximate measurement random error for these three methods are recalled from Section II (adjusted for clarity):

Table 3-1. Ice Basket Mass Measurement Random Error Mass Determination Method Measurement Random Error Ns)

Manual Lifting Using Scale k 15 lb Trending Using ICEMANm Code t 40 lb Visual Inspection I 300 lb Notes:

1. The error given for these measurement techniques is approximate and listed for reference only. Plant-specific maintenance procedures will qualify the processes used.

2. The error values shown may not be equal to the one-sigma random error defined in Equation 3.2.

Plant-specific procedures will determine the appropriate value to use in Equation 3.2 and will normally represent about two standard deviations for any alternate mass detmination method.

The effect of varying uncertainty when utilizing different mass deternination methods can be accounted for in several ways:

1.

The measurement random error can be conservatively treated as a bias and either deducted from the measured basket mass or added to the minimum required total mean mass (as was done historically).

2.

The error of the mean can be utilized, which more realistically deals with the error. The variation of each measurement made consists of a combination of the actual variation in the population (i.e.,

TOPICAL REPORT ICUG-001, Revision 2 III-7 June 2003

the variation of the process) and the variation due to the measurement error (i.e., the variation of the measurement). In this approach, the error of the measurement technique propagates to the standard error of the mean (see Equation 3.2). As discussed previously, the effect of errors associated with ice nass determination is conservatively accounted for in Equation 3.2, since the equation assumes the standard deviation of the sarnple, s, is the true value. The value of s calculated, however, will very likely be greater (more conservative) because it has some contribution from the measurement error.

An example calculation using a representative ice basket mass distribution illustrates the effect of different mass determination methods on the total ice mass estimated by the statistical sampling plan for a typical ice bed Radial Zone (Zone A is considered for this example). The results are provided in Table 3-2, which illustrates:

The effect of using the visual inspection mass determination method.

The effect of using an expanded sample.

Table 3-2. Illustration of Effects of Altemate Mass Determination Methods and Expanded Sample - Radial Zone A Case Change In Total Ice Mass for Radial Zone All 30 sample baskets lifted with scale Base Individual ice basket mass determined by combination of mass determination methods (50%

-19443 lb lifted with scale, 500h estimated visually)

Individual ice basket mass determined by visual method only:

30-basket sample (initial)

-33724 lb

-basket-sample-(exp-nded-by-30)-

-12123-lb.

60-basket sample (expanded by 30)

-12123 lb.

90-basket saniple (expanded by 60)

-2807 lb Note: This illustration assumes the mean mass of the sample baskets remains constant and the standard deviation of the sample(s) remains constant at s = S30 = s60= so = 184.5 lb (which is taken from the example calculation in Appendix A for a stratified sample size of 30 ice baskets in Zone A). Therefore, the number of samples and the percentage of the sample masses determined visually vary in this example. In reality, the expanded sample mean and standard deviation would differ from the initial sample mean and standard deviation.

TOPICAL REPORT ICUG-001, Revision 2 June 2003 rn-8

Altemate Basket Selection Strategy In the event that an ice basket selected for the initial sample is found to be obstructed or stuck in such a way that its mass cannot be detenined by any available method, an alternate basket can be selected as a direct replacement for the obstructed basket in the sample group. An alternate selection will not affect the validity of the sample, provided that it is chosen randomly from the same Radial Zone and in the same vicinity as the initial selection. In addition, there must be limits placed on the repeat use of altemate selections to ensure that the same alternate basket is not always selected as a result of all other candidate baskets being obstructed. To be a representative replacement for the initial sample basket, the alternate selection must meet the following criteria:

1. The alternate sample selection must be from the same Radial Zone (e.g., Zone A, B, or C) as the initial sanple selection.

2. The alternate sample selection must be from the same Bay as the initial sample selection.

3. An alternate selection cannot be a repeated selection in the current surveillance, and cannot have been used as an analyzed alternate selection in the three most recent previous surveillances that included the Bay-Zone involved.

As discussed in Section I, this approach is reasonable since ice baskets in the same Radial Zone have similar mean mass characteristics and therefore may be considered statistically similar for ice mass sampling purposes. It further notes that maintenance of the ice bed using AIMM methodology ensures that extreme differences in ice basket masses across a given Radial Zone will not be realized. Therefore, baskets within the same Radial Zone will be considered representative of one another. Also, note that baskets within the same Radial Zone have the same probability of being selected as a primary sample.

Though the probability of being selected as an alternate is different than the probability of being selected as a primary, the 95% confidence interval for the Radial Zone is not invalidated. Restricting the baskets from which an alternate may be selected to the same Bay, and restricting the frequency with which a basket may serve as an alternate, reduces the likelihood that a large region of obstructed baskets is excluded from the surveillance sample. This approach for selecting alternate baskets also prevents regions of the ice bed (such as problematic radial rows) from being systematically eliminated from the parent population.

Aolications of Samnlinc Plan Figure 3-5 provides the error of the mean (see Equation 3.2) as a function of the fraction of the sample basket population measured by the visual inspection method for various sample sizes, assuming a standard deviation of 100 lb (which was selected considering typical values seen in ice condenser basket populations). The remaining fraction of the sample is measured by the lifting rig/scale method. These two methods were chosen because they envelope the error resulting from the ICEMAN' prediction, and thus provide conservative results. Note that while the error for visual inspection methodology is relatively large (+/-300 lb), its effect on the error of the mean relative to typical mean ice basket masses (between 1000 and 1500 lb of ice), is small. However, if the calculated mean ice basket mass of the sample propagates to a value near the minimum required total mean ice basket mass for a Radial Zone, the mass determination error and/or the sample size can make a significant difference.

TOPICAL REPORT ICUG-001, Revision 2 m-9 June 2003

Figure 3-5. Effect of Visual Estimation Measurement Error on the Error of the Mean for Various Sample Sizes I

I a-a-

-a a--

a--

a -

-a-

0 0

0 0

Sample Size

-36 72 108 144 0

0.1 0.2 0.3 0.4 0.5

0.

0.7 Fraction ofSample Measured Using Vlsual Method OIb error) 0.8 0.9 1

An example of the utilization of the ice mass statistical sampling plan is provided in Appendix A. The ice bed mean mass is determined for a hypothetical ice condenser plant as follows:

Sample sizes of 36, 72, 90, 108 and 144, with each sample group containing the subset of the next smaller sample group. The sample group is provided in Table 3-4 and repeated in Appendix A.

Note that the basket mass values given in Table 3-4 and Appendix A are assumed to have already been adjusted for systematic bias.

With and without stratified sampling (using three Radial Zones comprised of three sequential rows each).

Various ice mass determination methods, assuming the values shown in Table 3-1 are equivalent to the one standard deviation random error (a ).

As-found (pre-maintenance) individual ice basket mass is used.

The actual total ice bed mass in the example is 2,485,268 lb as calculated by totaling the individual ice basket masses (determined using various methods). Note from Table 3-3 that this value is greater than all of the total ice bed masses calculated with 95% confidence from the sample group. The example demonstrates that the total ice bed mass with 95% confidence will generally increase (getting closer to the actual total ice bed mass) with increased sample size. However, as can be seen from the non-stratified mass for the 108-basket sample size, this is not always the case, depending on the individual ice mass of the samples selected. Also, non-stratified sampling will result in a higher total mass than stratified sampling. This is due to the smaller sample size used in the calculation of the mean ice mass for the stratified group.

TOPICAL REPORT ICUG-001, Revision 2 June 2003 Em-1

The selection of sample size, sample configuration, and mass determination methods depends largely on how much error of the mean can be tolerated while still meeting specific technical specification criteria.

Table 3-3. Ice Bed Masses from Sample Group Total Ice Bed Mass at Sample Size Type of Sampling 95% Confidence (Note 2)

Not Stratified 2,447,985 lb 36 Stratified (Note )

2,372,078 lb Not Stratified 2,463,030 lb 72 Stratified (Note 1) 2,410,530 lb Not Stratified 2,456,726 lb 90 Stratified (Note 1) 2,409,810 lb Not Stratified 2,458,818 lb 108 Stratified (NoW 1 2,417,634 lb Not Stratified 2,475,670 lb 144 Stratified (Note 1) 2,440,296 lb Notes:

(1) Uses three Radial Zones with three sequential rows in each Zone. The same number of samples are taken from each Zone.

(2) Actual total ice bed mass is 2,485,268 lb as determined by totaling the individual ice basket masses (which were determined using various methods). See Appendix A for the parent population ice basket data, which was based on basket mass data from the seven units of record.

Table 3-4 summarizes the sample baskets selected from Table A-I that were used in calculating the mass values in Table 3-3:

TOPICAL REPORT ICUG-001, Revision 2 June 2003 i-II

Table 3-4. Ice Mass Sample Group Basket Number Row Column Bay RadialZone Mass Method 124 1

7 14 C

1350 Visual 158 1

5 18 c

1325 Visual 127 1

1 15 C

1532 Scale 26 1

8 03 C

1050 Visual 92 1

2 11 C

1322 Visual 178 1

7 20 C

1538 ICEMANT m 86 1

5 10 C

1678 ICEMANT m 163 1

1 19 C

1101 Visual 105 1

6 12 C

1356 Scale 171 1

9 19 C

1278 Visual 195 1

6 22 c

1500 Visual 73 1

1 09 C

1365 Visual 29 1

2 04 C

1884 Scale 14 1

5 02 C

1145 Visual 22 1

4 03 C

1300 Visual 149 1

5 17 C

1400 Visual 265 2

4 06 C

1500 Visual 334 2

1 14 C

1468 ICEMANT 337 2

4 14 C

1433 ICEMANTm 425 2

2 24 C

1198 Scale 386 2

8 19 C

1412 Visual 264 2

3 06 C

1643 ICEMANT 221 2

5 01 C

1374 Scale 322 2

7 12 C

1485 Scale 364 2

4 17 C

1283 Visual 226 2

1 02 C

1100 Visual 391 2

4 20 C

1383 Scale 379 2

1 19 C

1199 Visual 310 2

4 11 C

1356 Visual 292 2

4 09 C

1245 Visual 332 2

8 13 C

1436 Scale 287 2

8 08 C

1347 Scale 478 3

1 06 C

1516 ICEMANTw 492 3

6 07 C

1478 Scale 628 3

7 22 C

1413 Scale 487 3

1 07 C

1450 Scale 463 3

4 04 C

1426 Scale 456 3

6 03 C

1506 Scale 605 3

2 20 C

1421 Scale 450 3

9 02 C

1329 Scale 638 3

8 23 C

1458 Scale 542 3

2 13 C

1334 Scale 620 3

8 21 C

1367 Scale 501 3

6 08 C

1392 Scale 625 3

4 22 C

1503 Scale 464 3

5 04 C

1415 Scale TOPICAL REPORT ICUG-001, Revision 2 1-12 June 2003

Table 3-4. Ice Mass Sample Group (continued)

Basket Number Row Column Bay RadialZone Mass Method 519 3

6 10 C

1438 Scale 534 3

3 12 C

1425 Scale 811 4

1 19 B

1411 Scale 777 4

3 15 B

1218 Scale 823 4

4 20 B

1243 Scale 756 4

9 12 B

1298 Scale 842 4

5 22 B

1345 Scale 688 4

4 05 B

1264 Scale 725 4

5 09 B

1255 Scale 651 4

3 01 B

1306 Scale 702 4

9 06 B

1291 Scale 746 4

8 11 B

1397 Scale 714 4

3 08 B

1207 Scale 788 4

5 16 B

1247 Scale 805 4

4 18 B

1211 Scale 650 4

2 01 B

1320 Scale 778 4

4 15 B

1202 Scale 706 4

4 07 B

1344 Scale 883 5

1 03 B

1366 Scale 867 5

3 01 B

1248 Scale 935 5

8 08 B

1195 Scale 994 5

4 15 B

1265 Scale 936 5

9 08 B

1326 Scale 975 5

3 13 B

1329 Scale 990 5

9 14 B

1233 Visual 934 5

7 08 B

1170 Scale 917 5

8 06 B

1233 Scale 1022 5

5 18 B

1244 Scale 952 5

7 10 B

1305 Scale 887 5

5 03 B

1314 Scale 987 5

6 14 B

1246 Scale 898 5

7 04 B

1190 Scale 939 5

3 09 B

1185 Scale 1059 5

6 22 B

1207 Scale 1183 6

4 12 B

1258 Scale 1244 6

2 19 B

1230 Scale 1146 6

3 08 B

1159 Scale 1181 6

2 12 B

1225 Scale 1267 6

7 21 B

1110 Scale 1258 6

7 20 B

1192 Scale 1136 6

2 07 B

1183 Scale 1167 6

6 10 B

1363 Scale 1132 6

7 06 B

1338 Scale 1173 6

3 11 B

1212 Scale 1121 6

5 05 B

1218 Scale 1267 6

7 21 B

1110 Scale TOPICAL REPORT ICUG-001, Revision 2 June 2003 M-13

Table 3-4. Ice Mass Sample Group (continued)

Basket Number Row Column Bay Radial Zone Mass Method 1256 6

5 20 B

1149 Scale 1175 6

5 11 B

1288 Scale 1163 6

2 10 B

1198 Scale 1273 6

4 22 B

1342 Scale 1490 7

5 22 A

1383 Visual 1510 7

7 24 A

1292 Scale 1342 7

1 06 A

1277 Visual 1487 7

2 22 A

1216 Scale 1397 7

2 12 A

1267 Visual 1378 7

1 10 A

1267 Visual 1498 7

4 23 A

1284 Scale 1436 7

5 16 A

1172 Visual 1368 7

9 08 A

1278 Visual 1301 7

5 01 A

1311 Scale 1371 7

3 09 A

1193 Scale 1506 7

3 24 A

1130 Scale 1323 7

9 03 A

1130 Scale 1466 7

8 19 A

1209 Visual 1421 7

8 14 A

1739 ICEMAN TrM 1367 7

8 08 A

1445 Visual 1604 8

2 11 A

1497 Visual 1625 8

5 13 A

1362 Visual 1709 8

8 22 A

1449 Scale 1664 8

8 17 A

1406 Visual 1536 8

6 03 A

904 Visual 1571 8

5 07 A

1358 Visual 1528 8

7 02 A

838 Scale 1660 8

4 17 A

1378 Visual 1520 8

8 01 A

770 Scale 1636 8

7 14 A

1330 Scale 1650 8

3 16 A

1202 Scale 1514 8

2 01 A

1429 Visual 1634 8

5 14 A

1181 Visual 1519 8

7 01 A

1090 Scale 1606 8

4 11 A

1376 Visual 1594 8

1 10 A

1240 Scale 1803 9

3 09 A

1286 Scale 1909 9

1 21 A

1243 Visual 1767 9

3 05 A

1367 Visual 1743 9

6 02 A

938 Visual 1802 9

2 09 A

1121 Visual 1731 9

3 01 A

1536 Visual 1934 9

8 23 A

1159 Visual 1886 9

5 18 A

1434 Visual 1939 9

4 24 A

1349 Visual 1932 9

6 23 A

1297 Visual TOPICAL REPORT ICUG-001, Revision 2 June 2003

! m-14

Table 3-4. Ice Mass Sample Group (continued)

Basket Number Row Column Bay Radial Zone Mass Method 1846 9

1 14 A

1291 Visual 1757 9

2 04 A

1230 l

Scale 1875 9

3 17 A

1414 Visual 1905 9

6 20 A

902 Scale 1799 9

8 08 A

1448 Visual 1775 9

2 06 A

1500 Visual Detailed Analysis: Radial Zone A Table 3-3 summarized the total ice mass that would be predicted with 95% confidence using various sample sizes for both stratified and non-stratified sample groups. To illustrate this calculation of mass using Equation 3.2 on a Radial Zone (stratified) basis, the 90-basket sample size is selected and the three Radial Zone sample groups are equally divided into 30 baskets each. Further, Radial Zone A (consisting of rows 7, 8, and 9) was selected as a test case, since this zone contains ice baskets that are subject to the highest sublimation rates and therefore will be the most likely candidates for alternate methods of mass determination. As Equation 3.2 allows these different methodologies for alternate mass determination to be evaluated separately, for this illustration baskets are chosen from Table 3-4 (the original sample group from the Table A-i ice bed) that have been evaluated using all of the three methods defined (scale, ICEMANTm prediction, and visual estimation). The mass values from Table 3-4, as noted previously, are already assumed to be corrected for systematic bias, and the random error values associated with each of the different mass determination methods as indicated in Table 3-1 are used to determine the minimum expected mass for each sample basket.

Table 3-5 summarizes the ice basket mass data for the 30-basket sample group representing Radial Zone A:

TOPICAL REPORT ICUG-001, Revision 2 M-15 June 2003

Table 3-5. Radial Zone A Sample Group Sample oW Table 3-4 As-Found ICEMAN' As-found Value Carried Minimum Number Basket Mass via Projected Visually to Equation 3.2 Mass Number Lifting Mass Estimated (b, corrected for, (lb, corrected

(lb):

(lb)

L Mass (lb) systematic bias) for uncertainty, I

S. :.. -.

see Note 1) 1 7

1510 1292 1292 1277 2

7 1487 1216 1216 1201 3

7 1498 1284 1284 1269 4

7 1301 1311 1311 1296 5

7 1371 1193 1193 1178 6

7 1506 1130 1130 1115 7

7 1323 1130 1130 1115 8

7 1421 Stuck 1739 1739 1699 9

7 1367 Stuck 1445 1445 1145 10 8

1625 Stuck 1362 1362 1062 11 8

1709 1449 1449 1434 12 8

1664 Stuck 1406 1406 1106 13 8

1519 1090 1090 1075 14 8

1650 1202 1202 1187 15 8

1636 1330 1330 1315 16 8

1514 Stuck 1429 1429 1129 17 8

1606 Stuck 1376 1376 1076 18 9

1803 1286 1286 1271 19 9

1909 Stuck 1243 1243 943 20 9

1731 Stuck 1536 1536 1236 21 9

1886 Stuck 1434 1434 1134 22 9

1939 Stuck 1349 1349 1049 23 9

1932 Stuck 1297 1297 997 24 9

1846 Stuck 1291 1291 991 25 9

1757 1230 1230 1215 26 9

1875 Stuck 1414 1414 1114 27 9

1905 902 902 887 28 9

1799 Stuck 1448 1448 1148 29 9

1775 Stuck 1500 1500 1200 30 9

1767 Stuck 1367 1367 1067

________Sample Mean Mass 1323 Sample Standard Deviation 157

_____Required Minimum Individual BasketMass 600 Note 1: Random error values: Scale = +/-15 lb, ICEMANIM = +40 lb, Visual Estimation = +300 lb, from Table 3-1. Systematic bias component of uncertainty has already been incorporated.

The mean mass of this sample group ( X ) is 1,323 lb, with a standard deviation of the mean (s) of 157 lb.

There are fourteen basket masses determined by scale, one by ICEMAN'm prediction, and fifteen by visual estimation. To determine the 95% confidence mean mass per basket (p,5) of this sample group, these values are input to Equation 3.2, along with the other appropriate values:

TOPICAL REPORT ICUG-001, Revision 2 June 2003 III-16

/95

=

Where:

= Mean mass per basket of Radial Zone A with 95% confidence X = Mean mass per basket of the sample group (1,323 lb) tg = critical value of t for a 30-basket sample size (1.7) s = standard deviation of the sample group (157 lb)

CF = (N

= Correction for a finite population

( 643)

= 0.954 in this case

'( N )

648) n = total number of baskets in sample (30)

N = total number of baskets in the population represented by the sample (648 in this case, for a three-row Radial Zone A configuration) ni = number of baskets within the sample whose mass is determined by method i (fourteen via scale, one via ICEMANrm prediction, and fifteen via visual estimation in this case) a, = the random error of the mass determination method i (+15 lb for scale, +/-40 lb for ICEMAN"" prediction, and +/-300 lb for visual estimation in this case)

Substituting the values:

P95 1,323 - 17 D x 0.954_+ 14(152) +1(402) +15(3Oo2) 2

= 132-17F(l~

3 0.94 302 195 =1,323-82 Therefore, p5= 1,241 lb per basket, with 95% confidence The total mass of Radial Zone A with 95% confidence, then, can be estimated as 804,168 lb (648 x 1,241). Similarly, random 30-basket sample groups are selected from Radial Zones B and C and evaluated. The total mass of the ice bed with 95% confidence is obtained by adding the three radial zone results together. In addition, as shown in the last column of Table 3-5, the minimum ice mass measurement for each basket in the sample groups is compared to the minimum allowed individual basket mass defined in Section I (600 lb per basket) to ensure there are no regions of localized degradation.

Assessment of the AIMM commitment to manage each ice basket above the required safety analysis mean mass would also be checked in this column, using the plant-specific per basket safety analysis mass value.

TOPICAL REPORT ICUG-001, Revision 2 IH-17 June 2003

Summary Based on the statistical sampling plan discussion and the evaluations of applications of the plan, the recommendations for the Ice Mass Technical Specification Statistical Sampling Plan are as shown in Table 3-6.

Table 3-6. Ice Mass Sampling Plan Recommendations Recommendation Basis

1. Perform stratified sampling using defined Stratified sampling allows sub-populations to be Radial Zones, with each zone containing defined and results in conservative estimates of rows of ice baskets that exhibit similar total ice mass. The evaluations in Section I show characteristics.

that ice baskets within Radial Zones A, B, and C (Figure 3-3) have similar mean mass characteristics.

2. Use at least 30 ice baskets in the initial As shown in Figure 3-2, 30 samples results in a sample for each Radial Zone.

reasonable value for the error ofthe mean for the sample (i.e., it is at the "knee" in the curve.)

3. If the minimum ice mass requirement in a The approach is consistent with the sampling plan Radial Zone cannot be met with the initial methodology and the expanded sample will 30-basket sample, expand the sample in the provide a reduction in error of the mean as Radial Zone as necessary (including the determined by Equation 3.2.

original 30 baskets).

4. If the mass cannot be determined for a As discussed in Section I, due to similar mean selected sample basket using any available mass, baskets from the same Radial Zone may be method, randomly select an alternate basket considered representative of one another for the from the vicinity of the initial selection as a purposes of sampling. AJMM methodology direct replacement in the sample.

ensures that extreme differences in basket masses within a Radial Zone will not occur. By also limiting the population of qualified alternates to the same Bay as the initial selection and limiting the frequency with which a basket can serve as an alternate, the likelihood that a large region of obstructed baskets will be excluded from the surveillance sample over time will be reduced.

TOPICAL REPORT ICUG-001, Revision 2 June 2003 ll-1 8

References

1. USNRC Safety Evaluation Report Related to Operation of Donald C. Cook Nuclear Plant Unit 1, Supplement 5, January 1976.

2. USNRC Safety Evaluation Supporting Amendment 18 to License DPR-58 (D.C. Cook), February 16, 1977.

3. AEP Corporation, "D.C. Cook Nuclear Plant Unit No. I - Long Term Evaluation of the Ice Condenser System - Results of the December 1974 Initial Ice Weighing Program," December 4, 1975.

4. AEP Corporation, D.C. Cook Nuclear Plant Unit No. 1 - Long Term Evaluation of Ice Condenser System - Results of the March 1975 Ice Weighing Program," June, 1975.

5. AEP Corporation, "D.C. Cook Nuclear Plant Unit No. 1 - Long Term Evaluation of the Ice Condenser System - Results of the July 1975 and October 1975 Ice Weighing Program," December 9, 1975.

6. AEP Corporation, "D.C. Cook Nuclear Plant Unit No. I - Long Term Evaluation of the Ice Condenser System - Results of the January 1976 and April 1976 Ice Weighing Programs," July 30, 1976.

7. AEP Corporation, "D.C. Cook Nuclear Plant Unit No. 1 - Long Term Evaluation of the Ice Condenser System - Results of the July 1976 and September 1976 Ice Weighing Programs," October 1, 1976.

8. Metcalfe, Andrew W., "Statistics in Engineering -

A Practical Approach," Chapman & Hall, Copyright 1994.

9. Witte, Robert S., "Statistics," Holt, Rinehart and Winston, Copyright 1980.

10. ANSI Standard N15.15-1974, "Assessment of the Assumption of Normality (Employing Individual Observed Values)."

11. NUREG/CR-4604, "Statistical Methods for Nuclear Material Management," December 1988.

12. NUREG-1475, "Applying Statistics," January 1995.

13. TID-26298, Jaech, John L., "Statistical Methods in Nuclear Material Control," December 1973.

14. Duke Energy Corp., McGuire Nuclear Station Final Safety Analysis Report, Revision 10/14/00, Section 6.2.1.1.3, "Loss of Coolant Accident Design Evaluation."

15. Duke Energy Corp., Catawba Nuclear Station Final Safety Analysis Report, Revision 4/8/00, Section 6.2.1.1.3, "Loss of Coolant Accident Design Evaluation."

16. Tennessee Valley Authority, Sequoyah Nuclear Plant Final Safety Analysis Report, Revision 5/4/98 (Rev. 14), Section 6.2.1.3.4, "Containment Pressure Transient - Long Term Analysis".

17. Tennessee Valley Authority, Watts Bar Nuclear Plant Final Safety Analysis Report, Amendment 2, Section 6.2.1, "Containment Functional Design".

TOPICAL REPORT ICUG-001, Revision 2 R-1 June 2003

18. American Electric Power Co., Donald C. Cook Nuclear Plant Final Safety Analysis Report, Revision 17.0, Section 5.3, "Ice Condenser".

19. ICUG Response to NRC Request for Additional Information, R.S Lytton letter to NRC dated June 12, 2002 (w/enclosure).

20. ICUG Response to NRC Request for Additional Information, R.S Lytton letter to NRC dated October 10, 2002 (w/enclosure).

21. ICUG Response to NRC Request for Additional Infornation, R.S Lytton letter to NRC dated October 22, 2002 (w/enclosures).

22. ICUG Response to NRC Request for Additional Information, R.S. Lytton letter to NRC dated November 26,2002 (w/enclosures).

23. Everhart, Jerry, Determining Mass Measurement Uncertainty, January 1997.

24. Abernathy, RB., et al, and Thomrpson, Jr., J.W., Measurement Uncertainty Handbook, January 1980.

25. McClave, James T., and Dietrich, Frank H., A First Course in Statistics, third edition, copyright 1989.

26. Eiseihart, C., Expression of Uncertainties of Final Results, Precision Measurement and Calibration, NBS Handbook 91, Vol. L February 1969.

27. USNRC Draft Safety Evaluation for Ice Condenser Utility Group Topical Report No. ICUG-001, Revision 0: Application of the Active Ice Mass Management Concept to the Ice Condenser Ice Mass Technical Specification, dated May 6, 2003 (w/enclosure).

TOPICAL REPORT ICUG-001, Revision 2 R-2 June 2003

Appendix A

• Figure A-1. Typical Ice Bed Arrangement and Identification

• Figure A-2. Typical Bay Map and Basket Identification

• Table A-1. Example Ice Bed Data

• Table A-2. Ice Mass Sample Group

• Table A-3. Example Calculations

• Original WOG Standard Technical Specification - Ice Bed TOPICAL REPORT ICUG-001, Revision 2 June 2003 A-1

Figure A-1. Typical Bay Arrangement and Identification 12 13 11 14 10 9

16 8

7 1

6 S

4 2

1 TOPICAL REPORT ICUG-OO1, Revision 2 June 2003 A-2

Figure A-2. Typical Bay Map and Basket Identification Containment Wall Crane Wall Basket ID is Column - Row TOPICAL REPORT ICUG-001, Revision 2 June 2003 A-3

Table A-1. Example Ice Bed Data FOR REFERENCE ONLY (Parent population for Section III example)

TOPICAL REPORT ICUG-OO1, Revision 2 A-4 June 2003

Basket ID Row Basket As-Found ICEMAN VISUAL Mass to Use Method Number Mass Projected Estimated (lb)

Used (lb)

Mass (lb)

Mass (lb) 2-01-1-1 1

1 Frozen 1150 1150 Visual 2-01-1-2 1

2 Frozen 1200 1200 Visual 2-01-1-3 1

3 Frozen 1479 1479 ICEMANTM 2-01-1-4 1

4 1328 1201 1328 Scale 2-01-1-5 1

5 1290 1290 Scale 2-01-1-6 1

6 909 1173 909 Scale 2-01-1-7 1

7 860 1183 860 Scale 2-01-1-8 1

8 680 1390 680 Scale 2-01-1-9 1

9 545 938 545 Scale 2-02-1-1 1

10 Frozen 1040 1040 Visual 2-02-1-2 1

11 Frozen 976 976 Visual 2-02-1-3 1

12 Frozen 1565 1565 ICEMANTm 2-02-1-4 1

13 Frozen 1619 1 619 ICEMANTm 2-02-1-5 1

14 Frozen 1145 1145 Visual 2-02-1-6 1

15 Frozen 1200 1200 Visual 2-02-1-7 1

16 1233 1692 1233 Scale 2-02-1-8 1

17 Frozen 1534 1534 ICEMANTm 2-02-1-9 1

18 Frozen 1755 1755 ICEMANTM 2-03-1-1 1

19 Frozen 1005 1005 Visual 2-03-1-2 1

20 Frozen 1582 1582 ICEMANTm 2-03-1-3 1

21 Frozen 1400 1400 Visual 2-03-1-4 1

22 Frozen 1300 1300 Visual 2-03-1-5 1

23 Frozenr1100 11 00 Visual 2-03-1-6 1

24 Frozer 1200 1200 Visual 2-03-1-7 1

25 Frozen

_1350 1350 Visual 2-03-1-8 1

26 Frzen 1050 1050 Visual 2-03-1-9 1

27 Frozer 1120 1120 Visual 2-04-1-1 1

28 Frozer 1034 1034 Visual 2-04-1-2 1

29 1884 1739 1884 Scale 2-04-1-3 1

30 Frozer 1400 1400 Visual 2-04-1-4 1

31 Frozen 1376 1376 Visual 2-04-1-5 1

32 Frozen 1256 1256 Visual 2-04-1-6 1

33 Frozen 1234 1234 Visual 2-04-1-7 1

34 Frozen 1300 1300 Visual 2-04-1-8 1

35 Frozen 1006 1006 Visual 2-04-1-9 1

36 Frozen IlOt 1100 1100 Visual 2-05-1-1 1

37 Frozen 1104 1104 Visual 2-05-1-2 1

38 1884 1884 Scale 2-05-1-3 1

39 1588 1588 Scale 2-05-14 1

40 Frozen 1301 1301 Visual 2-05-1-5 1

41 Frozen 1178 1178 Visual 2-05-1-6 1

42 Frozen 1256 1256 Visual 2-05-1-7 1

43 Frozen 1345 1345 Visual 2-05-1-8 1

44 Frozen 1527 1527 ICEMANTm 2-05-1-9 1

45 Frozen 1234 1234 Visual 2-06-1-1 1

46 Frozen 1123 1123 Visual 2-06-1-2 1

47 Frozen 1056 1056 Visual 2-06-1-3 1

48

Frozen, 1087 1087 Visual 2-06-1-4 1

49 Frozen 1400 1400 Visual TOPICAL REPORT ICUG-001, Revision 2 June 2003 A-S

2406-1-5 1

50 Frozen 1450 1450 Visual 24061-6 1

51 Frozen 1200 1200 Visual 2-06-17 1

52 Frozen 1300 1300 Visual 2-06-1-8 1

53 Frozen 1256 1256 Visual 2-06-1-9 1

54 Frozen 1398 1398 Visual 2-07-1-1 1

55 Frozen 1304 1304 Visual 2-07-1-2 1

56 Frozen 1298 1298 Visual 2-07-1-3 1

57 Frozen 1259 1259 Visual 2-07-1-4 1

58 Frozen 1199 1199 Visual 2-07-1-5 1

59 Frozen 1245 1245 Visual 2-07-1-6 1

60 Frozen 1300 1300 Visual 2-07-1-7 1

61 Frozen 1325 1325 Visual 2 1_-8 62 Frozen 1523 1523 ICEMANT 2-071 9 63 Frozen 1340 1340 Visual 2-08-1-1 1

64 1382 1382 Scale 208-1-2 1

65 1200 1218 1200 Scale 208-1-3 1

66 1100 1155 1

100 Scale 2-08-1-4 1

67 1214 1214 Scale 2-08-1-5 1

68 890 890 Scale 2-08-1-6 1

69 1202 1202 Scale 2-08-1-7 1

70 1326 1326 Scale 2-08-1-8 71 1251 1251 Scale 2408-1-9 1

72 Frozen 1456 1456 Visual 2409-1-1 73 Frozen 1365 1365 Visual 2 09-1-2 74 Frozen 1367 1367 Visual 209-1-3 1

75 Frozen 1298 1298 Visual 2-09-1.4 76 Frozen 1200 1200 Visual 2-09-1 -5

_77 Frozen 1378 1378 Visual 2-09-1 -6 78 Frozen 1000 1000 Visual 2409-1-7 _

79 Frozen 1562 1562 ICEMANTm 2409-1-8 1

80 1609 1679 1609 Scale 2 09-1-9 1

81 1427 1643 1427 Scale 2-_10-_1-1 1

82 Frozen 1245 1245 Visual 2-10-1-2 83 1704 1665 1704 Scale 2-10-1-3 184 1558 1617 1558 Scale 2-10-1-4 85 1487 1699 1487 Scale 2-10-1-5 1

86 Frozen 1678 1678 ICEMANW 2-10-1-6 87 1504 1449 1504 Scale 2-10-1-7 1

88 Frozen 1640 1640 ICEMAN 2 1 -8 89 Frozen 1665 1669 ICEMAN' 2 -_10-1-9 90 Frozen 1456 1456 Visual 2-11-1-1 91 Frozen 1400 1400 Visual 2-11-1-2 1

92 Frozen 1322 1322 Visual 2-11-1-3 I

93 Frozen 1256 1256 Visual 2-11-1-4 94 Frozen 1205 1205 Visual 2-1 5 195 Frozen 1156 1156 Visual 2-11-1-6 1

96 Frozen 987 987 Visual 2-11-1-7 1

97 Frozen 1457 1457 ICEMANTm 2-11-1-8 1

98 Frozen 945 945 Visual 2-11-1-9 I

99 Frozen 1467 1467 Visual

_2-12-1-1 I

100

Frozen, 1500 1500 Visual 12-12-1-2 1

1101 14145 14921 1445 Scale TOPICAL REPORT ICUG-001, Revision 2 June 2003 A-6

2-12-1-3 1

102 Frozen 1452 1452 ICEMA3NT 2-12-1-4 1

103 Frozen 1300 1300 Visual 2-12-1-5 1

= 104 Frozen 1117 1117 Visual 2-12-1-6 1

105 1356 1556 1356 Scale 2-12-1-7 1

106 Frozen 1302 1302 Visual 2-12-1-8 1

107 Frozen 1101 1101 Visual 2-12-1-9 1

108 Frozen 1034 1034 Visual 2-13-1-1 1

109 Frozen 1001 1001 Visual 2-13-1-2 1

110 1534 1514 1534 Scale 2-13-1-3 1

111 1300 1206 1300 Scale 2-13-1-4 1

112 1340 1326 1340 Scale 2-13-1-5 1

113 Frozen 1234 1234 Visual 2-13-1-6 1

114 Frozen 1002 1002 Visual 2-13-1-7 1

115 Frozen 1464 1464 ICEMANT 2-13-1-8 1

116 Frozen 1156 1156 Visual 2-13-1-9 1

117 Frozen 1400 1400 Visual 2-14-1-1 1

118 1485 1485 Scale 2-14-1-2 1

119 1399 1471 1399 Scale 2-14-1-3 1

120 1389 1344 1389 Scale 2-14-1-4 1

121 1302 1313 1302 Scale 2-14-1-5 1

122 Frozen 1250 1250 Visual 2-14-1-6 1

123 Frozen 1200 1200 Visual 2-14-1-7 1

124 Frozen 1350 1S0 Visual 2-14-1-8 1

125 Frozen 1000 1000 Visual 2-14-1-9 1

126 Frozen 1400 1400 Visual 2-15-1-1 1

127 1532 1662 1532 Scale 2-15-1-2 1

128 1632 1690 1632 Scale 2-15-1-3 1

129 1579 1622 1579 Scale 2-15-14 1

130 1473 1402 1473 Scale 2-15-1-5 1

131 1455 1378 1455 Scale 2-15-1-6 1

132 1437 1426 1437 Scale 2-15-1-7 1

133 1416 1424 1416 Scale 2-15-1-8 1

134 1509 1538 1509 Scale 2-15-1-9 1

135 1498 1475 1498 Scale 2-16-1-1 1

136 Frozen 1221 1221 Visual 2-16-1-2 1

137 Frozen 1574 1574 ICEMANTM 2-16-1-3 1

138 Frozen 1256 1256 Visual 2-16-1-4 1

139 Frozen 1302 1302 Visual 2-16-1-5 1

140 Frozen 1102 1102 Visual 2-16-1-6 1

141 Frozen 1267 1267 Visual 2-16-1-7 1

142 Frozen 1410a 1410 Visual 2-16-1-8 1

143 1620 1768 1620 Sce 2-16-1-9 1

144 Frozen 1342 1342 Visual 2-17-1-1 1

145 Frozen 1266 1266 Visual 2-17-1-2 1

146 Frozen 1234 1234 Visual 2-17-1-3 1

147 Frozen 1256 1256 Visual 2-17-1-4 1

148 Frozen 1187 1187 Visual 2-17-1-5 1

149 Frozen 1400 1400 Visual 2-17-1-6 1

150 Frozen 1205 1205 Visual 2-17-1-7 1

151 Frozen 1398 1398 ICEMANM 2-17-1-8 1

152 Frozen 1473 1473 ICEM MAN 2-17-1-9 1

153 Frozen 1233 123 Visual TOPICAL REPORT ICUG-001, Revision 2 June 2003 A-7

2-18-1-1 1

154 Frozen 1475 1475 Visual 2-18-1-2 1

155 Frozen 1098 1098 Visual 2-18-1-3 1

156 1518 1591

_1518 Scale 2-18-1-4 1

157 Frozen 1300 1300 Visual 2-18-1-5 1

158 Frozen 1325 1325 Visual 2-18-1-6 1

159 Frozen 1203 1203 Visual 2-18-1-7 1

160 Frozen 1175 1175 Visual 2-18-1-8 1

161 Frozen 1434 1434 Visual 2-18-1-9 1

162 Frozen 1400 1400 Visual 2-19-1-1 1

163 Frozen 1101 1101 Visual 2-19-1-2 1

164 1600 1531 1600 Scale 2-19-1-3 1

165 Frozen 1236 1236 Visual 2-19-1-4 1

166 Frozen 1056 1056 Visual 2-19-1-5 1

167 Frozen 1500 1500 Visual 2-19-1-6 1

168 Frozen 1456 1456 Visual 2-19-1-7 1

169 Frozen 1300 1300 Visual 2-19-1-8 1

170 Frozen 1757 1757 ICEMANT' 2-19-1-9 1

171 Frozen 1278 1278 Visual 2-20-1-1 1

172 Frozen 1334 1334 Visual 2-20-1-2 1

173 1518 1485 1518 Scale 2-20-1-3 1

174 1500 1296 1500 Scale 2-20-1-4 1

175 Frozen 1233 1233 Visual 2-20-1-5 1

176 Frozen 1544 1544 ICEMANTm 2-20-1-6 1

177 Frozen 1306 1306 ICEMAN 2-20-1-7 1

178 Frozen 1538 1538 ICEMANTm 2-20-1-8 1

179 Frozen 1590 1590 ICEMANTm 2-20-1-9 1

180 Frozen 1640 1640 ICEMANTm 2-21-1-1 1

181 1256 1344 1256 Scale 2-21-1-2 1

182 1251 1401 1251 Scale 2-21-1-3 1

183 1156 1172 1156 Scale 2-21-1-4 1

184 1172 991 1172 Scale 2-21-1-5 1

185 897 1097 897 Scale 2-21-1-6 1

186 1158 1144 1158 Scale 2-21-1-7 1

187 1512 1507 1512 Scale 2-21-1-8 1

188 Frozen 1432 1432 ICEMANm 2-21-1-9 1

189 Frozen 1256 1256 Visual 2-22-1-1 1

190 Frozen 1234 1234 Visual 2-22-1-2 1

191 Frozen 1075 1075 Visual 2-22-1-3 1

192 Frozen 1104 1104 Visual 2-22-1-4 1

193 Frozen 1189 1189 Visual 2-22-1-5 1

194 Frozen 1400 1400 Visual 2-22-1-6 1

195 Frozen 1500 1500 Visual 2-22-1-7 1

196 Frozen 1614 1614 ICEMANTm 2-22-1-8 1

197 Frozen 1536 1536 Visual 2-22-1-9 1

198 1347 1347 Scale 2-23-1-1 1

199 Frozen 1500 1500 Visual 2-23-1-2 1

200 Frozen 1467 1467 Visual 2-23-1-3 1

201 Frozen 1536 1536 ICEMANTm 2-23-1-4 1

202 Frozen 1523 1523 ICEMANTm 2-23-1-5 1

203 Frozen 1421 1421 ICEMANTm 2-23-1-6 1

1204 Frozen 1420 1420 Visual 2-23-1-7 1

1205 Frozen 1500 1500 Visual TOPICAL REPORT ICUG-001, Revision 2 A-8 June 2003

2-23-1-8 1

206 Frozen 1221 1221 Visual 2-23-1-9 1

207 Frozen 1122 1122 Visual 2-24-1-1 1

208 1320 1371 1320 Scale 2-24-1-2 1

209 1150 1155 1150 Scale 2-24-1-3 1

210 1264 1190 1264 Scale 2-24-14 1

211 Frozen 1145 1145 Visual 2-24-1-5 1

212 Frozen

. 1278 1278 Visual 2-24-1-6 1

213 Frozen 1 007 1007 Visual 2-24-1-7 1

214 Frozen 985 985 Visual 2-24-1-8 1

215 Frozen 1200 1200 Visual 2-24-1-9 1

216 Frozen 1365 1365 Visual 2-01-2-1 2

217 Frozen 1345 1345 Visual 2-01-2-2 2

218 Frozen 1202 1202 Visual 2-01-2-3 2

219 1388 1687 1388 Scale 2-01-2-4 2

220 1436 1211 1436 Scale 2-01-2-5 2

221 1374 1532 1374 Scale 2-01-2-6 2

222 Frozen 1245 1245 Visual 2-01-2-7 2

223 1002 1200 1002 Scale 2-01-2-8 2

224 1082 1186 1082 Scale 2-01-2-9 2

225 i 180 1136 1180 Scale 2-02-2-1 2

226 Frozen 1100 1 100 Visual 2-02-2-2 2

227 1357 1308 1357 Scale 2-02-2-3 2

228 1271 1266 1271 Scale 2-02-2-4 2

229 1305 1268 1305 Scale 2-02-2-5 2

230 1090 1214 1090 Scale 2-02-2-6 2

231 Frozen 1123 1123 Visual 2-02-2-7 2

232 1267 1286 1267 Scale 2-02-2-8 2

233 1371 1336 1371 Scale 2-02-2-9 2

234 1387 135S 1387 Scale 2-03-2-1 2

235 Frozen 1003 1003 Visual 2-03-2-2 2

236 1602 1491 1602 Scale 2-03-2-3 2

237 Frozen 1174 1174 Visual 2-03-2-4 2

238 Frozen 1009 1009 Visual 2-03-2-5 2

239 Frozen 1300 1300 Visual 2-03-2-6 2

240 Frozen 1477 1477 Visual 2-03-2-7 2

241 Frozen 1468 1468 Visual 2-03-2-8 2

242 Frozen 1512 1512 Visual 2-03-2-9 2

243 Frozen 958 958 Visual 2-04-2-1 2

244 Frozen 1189 1189 Visual 2-04-2-2 2

245 1595 1628 1595 Scale 2-04-2-3 2

246 Frozen 1484 1484 Visual 2-04-2-4 2

247 Frozen 1233 1233 Visual 2-042-5 2

248 Frozen 1528 1528 Visual 2404-2-6 2

249 Frozen 1101 I lOl Visual 2-04-2-7 2

250 Frozen 1135 1135 Visual 2-04-2-8 2

251 Frozen 1182 1182 Visual 2-04-2-9 2

252 Frozen 1620 1620 ICEMAN 2-05-2-1 2

253 Frozen 1400 1400 Visual 2-05-2-2 2

254 1434 1434 1434 Scale 2-05-2-3 2

255 1528 1461 1528 Scale 2-05-2-4 2

256 1439 1391 1439 Scale 2-05-2-5 2

257 Frozen 13451 1345Visual TOPICAL REPORT ICUG-001, Revision 2 A-9 June 2003

2-05-6 l2 l258 l

Frozen l

1398 1398 Visual 2-05-2-7 2

259 1494 1457 1494 Scale 2-05-2-8 2

260 1396 1576 1396 Scale 2-05-2-9 2

261 1433 1438 _

1433 Scale 2062-1 2

262 Frozen 1467 1467 Visual 24

_2-2 2 263 Frozen 1536 1536 Visual 20_2-3 2

264 Frozen 1643 1643 ICEMANTm 2-06_2-4 2

265 Frozen 1500 1500 Visual 24_2-5 2

266 Frozen 1512 1512 Visual 24)62-6 2

267 Frozen 1434 1434 Visual 246-2-7 2

268 Frozen 1365 1365 Visual 24)2-8 2

269 Frozen 1599 1599 ICEMANTM 24)62-9 2

270 Frozen 1200 1200 Visual 207-2-1 271 Frozen 1340 1340 Visual 2-07-2-2 2

272 Frozen 1134 1134 Visual 2-07-2-3 2

273 Frozen 1176 1176 Visual 2-07-2-4 2

274 Frozen 1186 1186 ICEMANm 2-07-2-5 2

275 Frozen 1204 1204 Visual 2-07 2

276 Frozen 1330 1330 Visual 2-07-2-7 2

277 1612 1538 1612 Scale 2_07-2-8 2

278 1540 1516 1540 Scale 2-07-2-9 2

279 Frozen 1480 1480 ICEMANTm 2-08-2-1 2

280 1437 1383 1437 Scale 2_08-2-2 2

281 1284 1267 1284 Scale 2_08-2-3 2

282 1193 1214 1193 Scale 2-08-2-4 2

283 1182 1182 Scale 2-08-2-5 2

284 1067 1067 Scale 2-08-2-6 2_285 1149 1149 Scale 2-08-2-7 2

286 1211 1252 1211 Scale 2-08-2-8 2

287 1347 1356 1347 Scale 2-08-2-9 2_288 1389 1422 1389 Scale 2-09 1 2

289 Frozen 1607 1607 ICEMANTm 2-09-2-2 290 1546 1634 1546 Scale 2-09-2-3 2

291 1600 1554 1600 Scale 2-09-24 2

292 Frozen 1245 1245 Visual 2-09 2

293 X Frozen 1400 1400 Visual 2-09-2-6 2

294 Frozen 1502 1502 Visual 2-09-2-7 2

295 1500 1560 1500 Scale 2-09-2-8 2_296 1465 1472 1465 Scale 2-09-2-9 297 1404 1593 1404 Scale 2-10-2-1 298 Frozen 1499 1499 Visual 2-10-2-2 2299 1618 1607 1618 Scale 2-102-3 2300 1472 1660 1472 Scale 2-10-2-4 2

301 1446 1440 1446 Scale 2-10-2-5 302 1270 1279 1270 Scale 2-10-2-6 2

303 1437 1473 1437 Scale 2-10-2-7 2

304 1583 1616 1583 Scale 2-10-2-8 2

305 1552 1556 1552 Scale 2-10-2-9 2

306 Frozen 1345 1345 Visual 2-11-2-1 2

.307 Frozen 1288 1288 Visual 2-11-2-2 2

308 1542 1542 Scale 2-11-2-3 2

309 Frozen 1378 1378 Visual TOPICAL REPORT June 2003 ICUG-001, Revision 2 A-10

2-11-24 2

310 Frozen 1356 1356 Visual 2-11-2-5 2

311 Frozen 1645 1645 Visual 2-11-2-6 2

312 Frozen 1233 1233 Visual 2-11-2-7 2

313 1590 1639 1590 Scale 2-11-2-8 2

314 1568 1605 1568 Scale 2-11-2-9 2

315 Frozen 1642 1642 ICEMAN'm 2-12-2-1 2

316 Frozen 1445 1445 ICEMANT_

2-12-2-2 2

317 1542 1540 5 S42 Scale 2-12-2-3 2

318 Frozen 1645 1645 ICEMANTm 2-12-2-4 2

319 Frozen 1500 1500 Visual 2-12-2-5 2

320 Frozen 1400 1400 Visual 2-12-2-6 2

321 1507 1544 1507 Scale 2-12-2-7 2

322 1485 1567 1485 Scale 2-12-2-8 2

323 1555 1574 15S5 Scale 2-12-2-9 2

324 Frozen 1305 1305 Visual 2-13-2-1 2

325 Frozen 1243 1243 Visual 2-13-2-2 2

326 1488 1533 1488 Scale 2-13-2-3 2

327 1476 1502 1476 Scale 2-13-2-4 2

328 1442 1515 1442 Scale 2-13-2-5 2

329 Frozen 1451 14Si ICEMANm 2-13-2-6 2

330 1446 1506 1446 Scale 2-13-2-7 2

331 1442 1514 1442 Scale 2-13-2-8 2

332 1436 1462 1436 Scale 2-13-2-9 2

333 Frozen 1259 1259 Visual 2-14-2-1 2

334 Frozen 1468 1468 AN 2-14-2-2 2

335 1340 1359 1340 Scale 2-14-2-3 2

336 1233 1412 1233 Scale 2-14-2-4 2

337 Frozen 1433 1433 ICEMAN 2-14-2-5 2

338 Frozen 1134 1134 Visual 2-14-2-6 2

339 1393 1393 Scale 2-14-2-7 2

340 1311 1297 1311 Scale 2-14-2-8 2

341 1340 1398 1340 Scale 2-14-2-9 2

342 1360 1360 Scale 2-15-2-1 2

343 1501 1620 1501 Scale 2-15-2-2 2

344 1471 1523 1471 Scale 2-15-2-3 2

345 1431 1471 1431 Scale 2-15-2-4 2

346 1366 1309 1366 Scale 2-15-2-5 2

347 1253 1279 1253 Scale 2-15-2-6 2

348 1327 1371 1327 Scale 2-15-2-7 2

349 1382 1381 1382 Scale 2-15-2-8 2

350 1486 1432 1486 Scale 2-15-2-9 2

351 1407 1290 1407 Scale 2-16-2-1 2

352 1573 1573 Scale 2-16-2-2 2

353 1495 1565 1495 Scale 2-16-2-3 2

354 1521 1521 Scale 2-16-2-4 2

355 1453

_1453 Scale 2-16-2-5 2

356 Frozen 1504 1504 Visual 2-16-2-6 2

357 Frozen 1403 1403 Visual 2-16-2-7 2

358 1760 1760 Scale 2-16-2-8 2

359 1663 1509 1663 Scale 2-16-2-9 2

360

Frozen, 1400 1400 Visual 2-17-2-1 12 361 Frozen_

1348 134 Visiial TOPICAL REPORT ICUG-001, Revision 2 June 2003 A-ll

2-17-2-2 2

362 1714 1516 1714 Scale 2-17-2-3 2

363 Frozen 1328 1328 Visual 2-17-2-4 2

364 Frozen 1283 1283 Visual 2-17-2-5 2

365 Frozen 1292 1292 Visual 2-17-2-6 2

366 1382 1504 1382 Scale 2-17-2-7 2

367 1440 1468 1440 Scale 2-17-2-8 2

368 1395 1444 1395 Scale 2-17-2-9 2

369 Frozen 1277 1277 Visual 2-18-2-1 2

370 1542 1542 Scale 2-18-2-2 2

371 1530 1530 Scale 2-18-2-3 2

372 Frozen 1304 1304 Visual 2-18-2-4 2

373 Frozen 1467 1467 Visual 2-18-2-5 2

374 Frozen 1134 1134 Visual 2-18-2-6 2

375 Frozen 1345 1345 Visual 2-18-2-7 2

376 Frozen 1507 1507 ICEMANm 2-18-2-8 2

377 Froze 1239 1239 Visual 2-18-2-9 2

378 Frozen 1143 1143 Visual 2-19-2-1 2

379 Frozer 1199 1199 Visual 2-19-2-2 2

380 1570 161 1570 Scale 2-19-2-3 2_381 Frozen 1478 1478 Visual 2-19-2_4 2

382 Frozen 1456 1456 Visual 2-19-2-5 2383 Frozen 1395 1395 Visual 2-19-2-6 2384

_Frozen 1362 1362 Visual 2-19-2-7 2

385 1585 1287 1585 Scale 2-19-2-8 2

386 Frozen 1412 1412 Visual 2-19-2-9 2

387 Frozen 1254 1254 Visual 2-20l_2-1 2388 1428 1567 1428 Scale 2-20_2-2 2

389 1406 1539 1406 Scale 2-20-2-3 2

390 1440 1458 1440 Scale 2-20-2-4 2

391 1383 1414 1383 Scale 2-20_2-5 2

392 1194 1274 1194 Scale 2-20-2-6 2

393 1436 1342 1436 Scale 2-20-2-7 2

394 147 1544 1478 Scale 2-20-2-8 2

395 1493 1495 1493 Scale 2-20_2-9 2

396 1574 14 1574 Scale 2-21-2-1 2

397 1252 1258 1252 Scale 2-21-2-2 2

398 1206 1219 1206 Scale 2-21-2-3 2399 1133 1161 1133 Scale 2-21 4 2400 1212i 1210 1212 Scale 2-21-2-5 2

401 1127 1138 1127 Scale 2-21-2-6 2

402 1158 1191 1158 Scale 2-21-2-7 2

403 1287 1385 1287 Scale 2-21-2-8 2

404 1432 1434 1432 Scale 2-21-2-9 2

405 Frozer 1235 123 Visual 2-22-2-1 2

406 Frozen 1478 1478 Visual 2-22-2-2 2407 150C 1494 1500 Scale 2-22-2-3 2

408 Frozen 1476 1476 Visual 2-22-2-4 2

409 Frozen 1401 1401 Visual 2-22-2-5 2410 Frozen 1341 1341 Visual 2-22-2-6 2411 Frozen 1222 1222 Visual 2-22-2-7 2

412 1538 1529 1538 Scale 2-22-2-8 2413 1485' 1485 Scale TOPICAL REPORT ICUG-001, Revision 2 June 2003 A-12

2-22-2-9 2

414 1472 1472 Scale 2-23-2-1 2

415 1521 1521 Scale 2-23-2-2 2

416 1564 1564 Scale 2-23-2-3 2

417 1550 1593 155 Scale 2-23-2-4 2

418 1489 1497 1489 Scale 2-23-2-5 2

419 1360 1366 1360 Scale 2-23-2-6 2

420 1454 1448 1454 Scale 2-23-2-7 2

421 Frozen 1584 1584 ICEMANTM 2-23-2-8 2

422 1537 1544 1537 Scale 2-23-2-9 2

423 Frozen 1145 1145 Visual 2-24-2-1 2

424 946 980 946 Scale 2-24-2-2 2

425 1198 1171 1198 Scale 2-24-2-3 2

426 1248 1329 1248 Scale 2-24-2-4 2

427 1254 1266 1254 Scale 2-24-2-5 2

428 1384 1384 Scale 2-242-6 2

429 Frozen 1134 1134 Visual 2-24-2-7 2

430 Frozen 1151

_Visual 2-24-2-8 2

431 Frozen 1074 1074 Visual 2-24-2-9 2

432 Frozen 921 921 Visual 2-01-3-1 3

433 1424 1282 1424 Scale 2-01-3-2 3

434 1518 1512 15 1 8 Scale 2-01-3-3 3

435 1468 1476 1468 Scale 2-01-3-4 3

436 1374 1357 1374 Scale 2-01-3-5 3

437 1227 1285 1227 Scale 2-01-3-6 3

438 1163 1312 1163 Scale 2-01-3-7 3

439 1216

_ 1221 1216 Scale 2-01-3-8 3

440 1122 1216 1122 Scale 2-01-3-9 3

441 909 923 909 Scale 2-02-3-1 3

442 Frozen 934 934 Visual 2-02-3-2 3

443 1200 1195 1200 Scale 2-02-3-3 3

444 1216 1208 1216 Scale 2-02-3-4 3

445 1398 1406 1398 Scale 2-02-3-5 3

446 1165 1238 1165 Scale 2-02-3-6 3

447 1182 1203 1182 Scale 2-02-3-7 3

448 1192 1212 1192 Scale 2-02-3-8 3

449 1240 1225 1240 Scale 2-02-3-9 3

450 1329 1339 1329 Scale 2-03-3-1 3

451 Frozen 1146 1146 Visual 2-03-3-2 3

452 1435 1426 1435 Scale 2-03-3-3 3

453 1434 1424 1434 Scale 2-03-3-4 3

454 1395 1351 1395 Scale 2-03-3-5 3

455 1508 1438 1508 Scale 2-03-3-6 3

456 1506 1523 1506 Scale 2-03-3-7 3

457 1491 1432 1491 Scale 2-03-3-8 3

458 1462 1424 1462 Scale 2-033 39 3

459

____Frozen 1378 1378 Visual 24)43-1 3

460 1439 1487 1439 Scale 2 04-3-2 3

461 1502 1478 1502 Scale 24

__3-3 3

462 1530 1461 1530 Scale 2-04-3-4 3 _463 1426 1445 1426 Scale 2404-3-5 13 1464 1415 1475 1415 Scale 2-04-3-6 13 1465 1444 1485 1444 Scale TOPICAL REPORT June 2003 ICUG-001, Revision 2 A-13

2-04-3-7 3

466 1468 1501 1 1468 Scale 2-04-3-8 3

467 1458 1486 1458 Scale 2404-3-9 3

468 1362 1419 1362 Scale 2-05-3-1 3

469 Frozen 1389 1389 ICEMANTM 2-05-3-2 3

470 1440 1466 1440 Scale 2-05-3-3 3

471 1356 1391 1356 Scale 2-05-3-4 3

472 1380 1467 1380 Scale 2-05-3-5 3

473 Frozen 1411 1411 Visual 2-05-3-6 3

474 1398 1433 1398 Scale 2-05-3-7 3

475 1322 1421 1322 Scale 2-05-3-8 3

476 1439 1452 1439 Scale 2-05-3-9 3

477 1392 1360 1392 Scale 2-06-3-1 3

478 Frozen 1516 1516 ICEMANTM 2-06-3-2 3

479 1419 1551 1419 Scale 2406-3-3 3

480 1580 1589 1580 Scale 2-063-4 3

481 Frozen 1500 1500 Visual 2-063-5 3

482 Frozen 1508 1508 ICEMANTm 2406-3-6 3

483 1454 1505 1454 Scale 24063-7 3

484 1374 1565 1374 Scale 2406-3-8 3

485 1530 1579 1530 Scale 2-06-3-9 3

486 Frozen 1453 1453 Visual 2-07-3-1 3

487 1450 1450 Scale 2-07-3-2 3

488 1502 1510 1502 Scale 2-07-3-3 3

489 1487 1503 1487 Scale 2-07-34 3

490 1474 1472 1474 Scale 2-07-3-5 3

491 1485 1422 1485 Scale 2-07-3-6 3

492 1478 1477 1478 Scale 2-07-3-7 3

493 1493 1499 1493 Scale 2-07-3-8 3

494 1500 1527 1500 Scale 2-07-3-9 3

495 1480 1523 1480 Scale 2-08-3-1 3

496 1350 1405 1350 Scale 2-08-3-2 3

497 1256 1296 1256 Scale 2-08-3-3 3

498 1270 1317 1270 Scale 2-08-3-4 3

499 1078 1120 1078 Scale 2-08-3-5 3

500 1126 1182 1126 Scale 2-08-3-6 3

501 1392 1392 Scale 2-08-3-7 3

502 1257 1252 1257 Scale 2-08-3-8 3

503 1310 1332 1310 Scale 2-08-3-9 3

504 1440 1200 1440 Scale 2-09-3-1 3

505 1480 1589 1480 Scale 2-09-3-2 3

506 1507 1487 1507 Scale 2-09-3-3 3

507 1540 1573 1540 Scale 2-09-34 3

508 1507 1620 1507 Scale 2-09-3-5 3

509 1435 1435 Scale 2-09-3-6 3

510 1454 1370 1454 Scale 2-09-3-7 3

511 1408 1434 1408 Scale 2-09-3-8 3

512 1404 1418

_1404 Scale 2-09-3-9 3

513 Frozen 1240 1240 Visual 2-10-3-1 3

514 1560 1553 1560 Scale 2-10-3-2 3

515 1498 1502 1498 Scale 2-10-3-3 3

516 1474 1479 1474 Scale 2-10-3-4 3

517 1407 1404 1407 Scale TOPICAL REPORT ICUG-001, Revision 2 A-14 June 2003

2-10-3-5 3

518 1369 1342 1369 Scale 2-10-3-6 3

519 1438 1457 1438 Scale 2-10-3-7 3

520 1468 1422 1468 Scale 2-10-3-8 3

521 1542 1514 1542 Scale 2-10-3-9 3

522 Frozen 1490 1490 Visual 2-11-3-1 3

523 1252 1514 1252 Scale 2-11-3-2 3

524 1494 1506 1494 Scale 2-11-3-3 3

525 1512 1511 1512 Scale 2-11-3-4 3

526 1531 1555 1531 Scale 2-11-3-5 3

527 Frozen 1283 1283 Visual 2-11-3-6 3

528 1523 1517 __

1523 Scale 2-11-3-7 3

529 1545 1557 1545 Scale 2-11-3-8 3

530 1544 1554 1544 Scale 2-11-3-9 3

531 1551 1572 1551 Scale 2-12-3-1 3

532 1470 1417 1470 Scale 2-12-3-2 3

533 1446 1470 _

1446 Scale 2-12-3-3 3

534 1425 1475 1425 Scale 2-12-3-4 3

535 1406 1402 1406 Scale 2-12-3-5 3

536 1390 1390 Scale 2-12-3-6 3

537 1384 1407 1384 Scale 2-12-3-7 3

538 1410 1428 1410 Scale 2-12-3-8 3

539 1454 1471 1454 Scale 2-12-3-9 3

540 1450 1385 1450 Scale 2-13-3-1 3

541 1297 1267 1297 Scale 2-13-3-2 3

542 1334 1374 1334 Scale 2-13-3-3 3

543 1362 1389 1362 Scale 2-13-3-4 3

544 1320 1378 1320 Scale 2-13-3-5 3

545 1338 1386 1338 Scale 2-13-3-6 3

546 1329 1368 1329 Scale 2-13-3-7 3

547 1318 1354 1318 Scale 2-13-3-8 3

548 1384 1451 1384 Scale 2-13-3-9 3

549 Frozen 1402 1402 Visual 2-14-3-1 3

550 1220 1375 1220 Scale 2-14-3-2 3

551 1302 1339 1302 Scale 2-14-3-3 3

552 1238 1330 X

1238 Scale 2-14-3-4 3

553 1238 1256 1238 Scale 2-14-3-5 3

554 Frozen 1440 1440 Visual 2-14-3-6 3

555 1176 1216 1176 Scale 2-14-3-7 3

556 1220 1271 1220 Scale 2-14-3-8 3

557 1277 1318 1277 Scale 2-14-3-9 3

558 Frozen 1207 1207 ICEMANTM 2-15-3-1 3

559 1406 1425 1406 Scale 2-15-3-2 3

560 1367 1383 1367 Scale 2-15-3-3 3

561 1315 1344 1315 Scale 2-15-3-4 3

562 1243 1278 1243 Scale 2-15-3-5 3

563 1228 1270 1228 Scale 2-15-3-6 3

564 1278 1300 1278 Scale 2-15-3-7 3

565 1287 1319 1287 Scale 2-15-3-8 3

566 1304 1338 1304 Scale 2-15-3-9 3

567 1345 1378 1345 Scale 2-16-3-1 3

568 1544 1375 1544 Scale 2-16-3-2 3

569 1370 1452 1370 Scale TOPICAL REPORT ICUG-001, Revision 2 June 2003 A-15

2-16-3-3 3

570 1400 1449 1400 Scale 2-16-3-4 3

571 1374 1442 1374 Scale 2-16-3-5 3

572 1392 1468 1392 Scale 2-16-3-6 3

573 1354 1400 1354 Scale 2-16-3-7 3

574 1402 1431 1402 Scale 2-16-3-8 3

575 1326 1369 1326 Scale 2-16-3-9 3

576 1391 1427 1391 Scale 2-17-3-1 3

577 1622 1406 1622 Scale 2-17-3-2 3

578 1548 1409 1548 Scale 2-17-3-3 3

579 1366 1389 1366 Scale 2-17-3-4 3

580 1337 1383 1337 Scale 2-17-3-5 3

581 1345 1384 1345 Scale 2-17-3-6 3

582 1387 1407 1387 Scale 2-17-3-7 3

583 1377 1405 1377 Scale 2-17-3-8 3

584 1372 1400 1372 Scale 2-17-3-9 3

585 1421 1523 1421 Scale 2-18-3-1 3

586 1480 1480 Scale 2-18-3-2 3

587 1425 1425 Scale 2-18-3-3 3

588 1411 1472 1411 Scale 2-18-3-4 3

589 1310 1375 1310 Scale 2-18-3-5 3

590 1396 1413 1396 Scale 2-18-3-6 3

591 1382 1422 1382 Scale 2-18-3-7 3

592 1449 1390 1449 Scale 2-18-3-8 3

593 1524 1497 1524 Scale 2-18-3-9 3

594 1552 1552 Scale 2-19-3-1 3

595 Frozen 1337 1337 Visual 2-19-3-2 3

596 1496 1528 1496 Scale 2-19-3-3 3

597 1484 1523 1484 Scale 2-19-3-4 3

598 1498 1518 1498 Scale 2-19-3-5 3

599 Frozen 1487 1487 Visual 2-19-3-6 3

600 1478 1504 1478 Scale 2-19-3-7 3

601 1474 1490 1474 Scale 2-19-3-8 3

602 1510 1558 1510 Scale 2-19-3-9 3

603 1436 1522 1436 Scale 2-20-3-1 3

604 1438 1477 1438 Scale 2-20-3-2 3

605 1421 1457 1421 Scale 2-20-3-3 3

606 1365 1408 1365 Scale 2-20-3-4 3

607 1271 1306 1271 Scale 2-20-3-5 3

608 1 288 1313 3

1288 Scale 2-20-3-6 3

609 1345 1371 1345 Scale 2-20-3-7 3

610 1399 1416 1399 Scale 2-20-3-8 3

611 1446 1452 1446 Scale 2-20-3-9 3

612 1291 1490 1291 Scale 2-21-3-1 3

613 1252 1259 1252 Scale 2-21-3-2 3

614 1205 1230 1205 Scale 2-21-3-3 3

615 1390 1392 1390 Scale 2-21-3-4 3

616 1341 1376 1341 Scale 2-21-3-5 3

617 1179 1212 1179 Scale 2-21-3-6 3

618 1167 1203 1167 Scale 2-21-3-7 3

619 1262 1290 1262 Scale 2-21-3-8 3

620 1367 1372 1367 Scale 2-21-3-9 3

621 Frozen 1254 1254 Visual TOPICAL REPORT ICUG-001, Revision 2 A-16 June 2003

2-22-3-1 3

622 1440 1440 Scale 2-22-3-2 3

623 1494 1584 1494 Scale 2-22-3-3 3

624 1465 1508 _

1465 Scale 2-22-3-4 3

625 1503 1426 1503 Scale 2-22-3-5 3

626 1464 1464 Scale 2-22-3-6 3

627 1420 1444 1420 Scale 2-22-3-7 3

628 1413 1435 1413 Scale 2-22-3-8 3

629 1370 1394 1370 Scale 2-22-3-9 3

630 1396 1482 1396 Scale 2-23-3-1 3

631 1414 1414 Scale 2-23-3-2 3

632 1445 1451 1445 Scale 2-23-3-3 3

633 1437 1437 1437 Scale 2-23-3-4 3

634 1406 1426 1406 Scale 2-23-3-5 3

635 1356 1367 1356 Scale 2-23-3-6 3

636 1392 1399 1392 Scale 2-23-3-7 3

637 1442 1451 1442 Scale 2-23-3-8 3

638 1458 1471 1458 Scale 2-23-3-9 3

639 1424 1401 1424 Scale 2-24-3-1 3

640 1136 1131 1136 Scale 2-24-3-2 3

641 1229 1262 1229 Scale 2-24-3-3 642 1156 1142 1156 Scale 2-24-34 3

643 1274 1302 1274 Scale 2=4-3-5 03

=

644 1281 1306 1281 Scale 2-24-3-6 3

645 1250 1255 1250 Scale 2-24-3-7 3

646 1348 1414 1348 Scale 2-24-3-8 3

647 1495 1485 1495 Scale 2-24-3-9 3

648 1442 1442 Scale 2-01-4-1 4

649 1318 1312 1318 Scale 2-01-4-2 4

650 1320 1267 1320 Scale 2-01-4-3 4

651 1306 1265 1306 Scale 2-014-4 4

62 1306 1312 1306 Scale 2-014-5 4

653 1223 1263 1223 Scale 2-014 6 4

654 1277 1311 1277 Scale 2-01-4-7 4

655 1209 1231 1209 Scale 2-01 4

656 1078 1205 1078 Scale 201-4-9 4

657 1054 l lQ 1054 Scale 2_02-4-1 4 _658 1165 1279 1165 Scale 2-02-4-2 4

659 1185 1163 1185 Scale 2-02-4-3 4

660 1197 1212 1197 Scale 2-024-4 4

661 1328 1339.

1328 Scale 2-02 4_5 4

662 1339 1339 Scale 2-02 46 4

663 1310 1328 1310 Scale 2-024-7 4664 1396 1415 1396 Scale 24 8

4 665 1140 1182 1140 Scale 2-024-9 4

666 1322 1322 1322 Scale 2-03-4-1 4667 1242 1242 Scale 2-03-4-2 4

668 1218 1254 1218 Scale 2-034-3 4

669 1274 1279 1274 Scale 2-03-4-4 4

670 1215 124 1215 Scale 2-03-4-5 4

671 1328 1286 1328 Scale 2-03-4-6 4

672 1268 1262 1268 Scale 2-03-4-7 4

673 1350 12981 1350 Scale TOPICAL REPORT ICUG-001, Revision 2 June 2003 A-17

2-03-4-8 4

674 1465 1465 Scale 2-03-4-9 4

675 1219 1134 1219 Scale 2-04-4-1 4

676 1294 1302 1294 Scale 244-4-2 4

677 1284 1302 1284 Scale 24-4-3 4

678 1288 1325 1288 Scale 24-4-4 4

679 1276 1296 1276 Scale 24-4-5 4

680 1302 1300 1302 Scale 24-4-6 4

681 1268 1286 1268 Scale 2-04-4-7 4

682 1268 1267 1268 Scale 2-04-4-8 4

683 1255 1274 1255 Scale 24-4-9 4

684 1209 1191 1209 Scale 2-05-4-1 4

685 1313 1252 1313 Scale 2-05-4-2 4

686 1308 1324 1308 Scale 2-05-4-3 4

687 1266 1293 1266 Scale 2-0544 4

688 1264 1253 1264 Scale 2-054-5 4

689 1340 1340 Scale 2-05-4-6 4

690 1293 1251 1293 Scale 2-05-4-7 4

691 1320 1268 1320 Scale 2-05-4-8 4

692 1332 1403 1332 Scale 2-05-4-9 4

693 1380 1429 1380 Scale 246-1 4

694 1377 1375 1377 Scale 2-06-4-2 4

695 1386 1399 1386 Scale 2464-3 4

696 1416 1432 1416 Scale 2-06-4-4 4

697 1405 1446 1405 Scale 2-06-4-5 4

698 1470 1388 1470 Scale 2-06-4-6 4

699 1405 1425 1405 Scale 2-06-4-7 4

700 1414 1441 1414 Scale 2-06-4-8 4

701 1428 1455 1428 Scale 2-06-4-9 4

702 1291 1380 1291 Scale 2-07-4-1 4

703 1 280 1 320 1280 Scale 2-07-4-2 4

704 1305 1329 1305 Scale 2-08-4-3 4

705 1389 1346 1389 Scale 2-0844 4

706 1 344 1 33 1 1 344 Scale 2-07-4-5 4

707 1342 1334 1342 Scale 2-074-6 4

708 1322 1364 1322 Scale 2-0074-7 4

709 1347 1334 1347 Scale 2-074-8 4

710 1338 1355 1338 Scale 2-074-9 4

711 1362 138 1362 Scale 2-084-1 4

712 1322 1351 1322 Scale 2-08-4-2 4

713 1206 1222 1206 Scale 2-084-3 4

714 1207 1240 1207 Scale 2-08-44 4

715 1128 1162 1128 Scale 2-08-4-5 4

716 1228 1240 1228 Scale 2-08416 4

717 1348 1443 1348 Scale 2-084-7 4

7R1E8 118 R

2 1182 Scale 2-084-8 4

719 1223 124 1223 Scale 24084-9 4720 1295 1279

.1295 Scale 2-09-4-1 4721 1462 1336 1462 Scale 2-09-4-2 4

722 1379 1379 1379 Scale 2-09-4-3 14723

1354, 1377 1354 Scale 2-094-4 14 1724 1

13641

1380, 1364 Scale 2-094-5 14 1725

-- 1 12551 13101 1255,Scale TOPICAL REPORT ICUG-001, Revision 2 A-18 Junc 2003

2-09-4-6 4

726 1351 1364 1351 Scale 2-09-4-7 4

727 1342 1328 1342 Scale 2-09-4-8 4

728 1349 1353 1349 Scale 2-094-9 4

729 1356 1397 1356 Scale 2-10-4-1 4

730 1400 1422 1400 Scale 2-10-4-2 4

731 1382 1267 1382 Scale 2-10-4-3 4

732 1347 1348 1347 Scale 2-10-4-4 4

733 1340 1347 1340 Scale 2-10-4-5 4

734 1344 1308 1344 Scale 2-10-4-6 4

735 1360 1377 1360 Scale 2-10-4-7 4

736 1385 1399 1385 Scale 2-10-4-8 4

737 1430 1434 1430 Scale 2-10-4-9 4

738 Frozen 1463 1463 Visual 2-114-1 4

739 1387 1402 1387 Scale 2-114 2 4

740 1374 1394 1374 Scale 2-11-4-3 4

741 1424 1445 1424 Scale 2-114-4 4

742 1444 1473 1444 Scale 2-11-4-5 4

743 1478 1491 1478 Scale 2-11-4-6 4

744 1434 1429 1434 Scale 2-11-4-7 4

745 1422 1425 1422 Scale 2-114-8 4

746 1397 1416 1397 Scale 2-11-4-9 4

747 1432 1463 1 432 Scale 2-124-1 4

748 1328 1331 1328 Scale 2-1242 4

749 1332 1386 1332 Scale 2-124-3 4

750 1322 1327 1322 Scale 2-1244 4

751 1343 1402 1343 Scale 2-12-4-5 4

752 1278 1296 1278 Scale 2-12-4-6 4

753 1264 1427 1264 Scale 2-12-4-7 4

754 1282 1294 1282 Scale 2-12-4-8 4

755 1322 1328 1322 Scale 2-12-4-9 4

756 1298 1317 1298 Scale 2-13-4-1 4

757 1314 1321 1314 Scale 2-13-4-2 4

758 1219 1228 1219 Scale 2-1343 4

759 1245 1264 1245 Scale 2-13-4-4 4

760 1247 1277 1247 Scale 2-134-5 4

761 1251 1239 1251 cale 2-13-4-6 4

762 1208 1183 1208 Scale 2-13-4-7 4

763 1314 1338 1314 Scale 2-13-4-8 4

764 1267 1325 1267 Scale 2-13-4-9 4

765 1349 1419 1349 Scale 2-14-4-1 4

766 1242 1276 1242 Scale 2-14-4-2 4

767 1205 1253 1205 Scale 2-144-3 4

768 1324 1347 1324 Scale 2-14-44 4

769 1170 1195__

1170___ Scale 2-144-5 4

770 1132 1161 1132 Scale 2-14-4-6 4

771 1187 1214 1187 Scale 2-144-7 4

772 1204 1230 1204 cale 2-14-4-8 4

773 1209 1204 1209 Scale 2-144-9 4

774

Frozen,

_5_6 1456 Visual 2-154-1 4

775 1228 1247 1228 Scale 2-154-2 4

776 1199 1225 1199 Scale 2-15-4-3 4

777 1218 12481 1218 Scale TOPICAL REPORT ICUG-001, Revision 2 A-19 June 2003

2-15-4-4 4

778 1202 1246 1202 Scale 2-15-4-5 4

779 1230 1317 1230 Scale 2-15-4-6 4

780 1233 1262 1233 Scale 2-15-4-7 4

781 1238 1270 1238 Scale 2-15-4-8 4

782 1218 1245 1218 Scale 2-15-4-9 4

783 1262 1298 1262 Scale 2-16-4-1 4

784 1239 1297 1239 Scale 2-16-4-2 478 1228 1285 1228 Scale 2-16-4-3 4

786 1254 1302 1254 Scale 2-16-4-4 4

787 1226 1296 1226 Scale 2-14-5 788 1247 1306 1247 Scale 2-16-4-6 4

789 1176 1176 Scale 2-164-7 4

790 1181 1213 1181 Scale 2-16-4-8 4

791 1167 1229 1167 Scale 2-164-9 4

792 1156 1215 1156 Scale 2-174-1 4

793 1338 1342 1338 Scale 2-17-4-2 4

794 1298 1368 1298 Scale 2-17-4-3 4

795 1 1294 1315 1294 Scale 2-17-4-4 4

796 1234 1257 1234 Scale 2-17-4-5 4

797 1321 1298 1321 Scale 2-17-4-6 X 4 798 1231 1283 1231 Scale 2-174-7 4

799 1254 1286 1254 Scale 2-17-4-8 4

800 1275 1285 1275 Scale 2-17-4-9 4801 1240 1272 1240 Scale 2-18 1 4

802 1274 1341 1274 Scale 2-18-4-2 4803 1294 1349 1294 Scale 2-18-4-3 4804 1250 1318 1250 Scale 2-18-4-4 4

805 1211 1388 1211 Scale 2-18-4-5 4

806 1245 1245 Scale 2-184-6 4

807 1285 1342 1285 Scale 2-18 4-7 4

808 1293 1344 1293 Scale 2-184-8 4809 1290 1332 1290 Scale 2-18_49 4

810 1241 1275 1241 Scale 2-194-1 4

811 1411 1439 1411 Scale 2-19-4-2 4

812 1361 1410 1361 Scale 2-19-4-3 4

813 1385 1434 1385 Scale 2-19-4-4 4

814 1387 1422 1387 Scale 2-19-4-5 4_815 Frozen 1320 1320 Visual 2-19-4-6 4

816 1385 1411 1385 Scale 2-19-4-7 4

817 1341 1371 1341 Scale 2-19-4-8 4

818 1327 1378 1327 Scale 2-19-4-9 4

819 1320 1358 1320 Scale 2-20-4-1 4

820 1239 1332 1239 Scale 2-20-4-2 4

821 1286 1328 1286 Scale 2-20-4-3 4

822 1259 1294 1259 Scale 2-20-4-4 4

823 1243 1285 1243 Scale 2-20-4-5 4

824 1231 1301 1231 Scale 2-20-4-6 4

825 1212 1293 1212 Scale 2-20-4-7 4

826 1301 1314 1301 Scale 2-20-4-8 4

827 1317 1382 1317 Scale 2-20-4-9 4

828 1408 1438 1408 Scale 2-21-4-1 4

829 1191 12161 1191 Scale TOPICAL REPORT ICUG-001, Revision 2 June 2003 A-20

2-214.2 4

830 1143 1164l l

1143 Scale 2-21-4-3 4

831 1161 110 l

1161 Scale 2-21-4-4 4

832 1357 1213 1357 Scale 2-214-5 4

833 1163 1163 Scale 2-214-6 4

834 1166 1209 1166 Scale 2-214-7 4

835 118C 1219 1180 Scale 2-214-8 4

836 1242 1265 1242 Scale 2-214-9 4

837 1297 1336 1297 Scale 2-22-4-1 4

838 1348 1368 1348 Scale 2-224-2 4

839 1322 1364 1322 Scale 2-22-4-3 4

840 1341 1362 1341 Scale 2-224-4 4

841 1348 1352 1348 Scale 2-22-4-5 4

842 1345 1345 Scale 2-224-6 4

843 1316 1339 1316 Scale 2-224-7 4

844 1273 1365 1273 Scale 2-224-8 4

845 1229 1267 1229 Scale 2-22-4-9 4

846 1226 1263 1226 Scale 2-23-4-1 4

847 1294 1304 1294 Scale 2-234-2 4

848 1292 1309 1292 Scale 2-234-3 4

849 1325 1321 1325 Scale 2-2344 4

850 1322 1340 1322 Scale 2-23-4-5 4

851 1282 1284 1282 Scale 2-234-6 4

852 1240 1236 1240 Scale 2-234-7 4

853 1280 1277 1280 Scale 2-234-8 4

854 1315 1302 1315 Scale 2-23-4-9 4

855 1288 1322 1288 Scale 2-24-4-1 4

l 856 1211 1090 1211 Scale 2-24-4-2 4

857 1188 1080 1188 Scale 2-24-4-3 4

858 1195 1243 1195 Scale 2-244-4 4

859 1234 1267 1234 Scale 2-244-5 4

860 1393 1296 1393 Scale 2-244-6 4

861 1250 1251 1250 Scale 2-244-7 4

862 1277 1290 1277 Scale 2-244-8 4

863 1288 1328 1288 Scale 2-24-4-9 4

864 1280 1307 1280 Scale 2-01-5-1 5

865 1198 1182 1198 Scale 2-01-5-2 5

866 1273 1255 1273 Scale 241-5-3 5

867 1248 1240 1248 Scale 2-01-5-4 5

868 1254 1248 1254 Scale 2-01-5-5 5

869 1221 1249 1221 Scale 2-01-5-6 5

870 1203 1250 1203 Scale 2-01-5-7 5

871 1173 1236 1173 Scale 2-01-5-8 5

872 1182 118S 1182 Scale 2-01-5-9 5

873 989 1094 989 Scale 2-02-5-1 5

874 1163 1163 Scale 2-02-5-2 5

875 1136 11 35 1136 Scale 2-02-5-3 5

876 1160 1164 1160 Scale 2-02-54 5

877 920 l l lS 920 Scale 2-02-5-5 5

878 1095 1126 1095 Scale 2-02-5-6 5

879 1063 1073 1063 Scale 2-02-5-7 5

880 1071 1159 1071 Scale 2-02-5-8 5

881 1075 11401 1075 Scale TOPICAL REPORT ICUG-001, Revision 2 A-21 June 2003

2-02-5-9 5

882 1110 1168 11 Scale 2-03-5-1 5

883 1366 1366lScale 2-03-5-2 5

884 1225 1215 1225 Scale 2-03-5-3 5

885 1151 1137 1151 Scale 2-03-5-4 5

886 1340 1339 1340 Scale 2-03-5-5 5

887 1314 1230 1314 Scale 2-03-5-6 5

888 1260 1210 1260 Scale 2-03-5-7 5

889 1265 1196 1265 Scale 2-03-5-8 5

890 1250 1209 1250 Scale 2-03-5-9 5

891 1260 1168 1260 Scale 2-04-5-1 5

892 1401 1285 1401 Scale 2-04-5-2 5

893 1354 1390 1354 Scale 244-5-3 5

894 1327 1335 1327 Scale 2-04-5-4 5

895 1296 1315 1296 Scale 2-04-5-5 5

896 1248 1268 1248 Scale 2-04-5-6 5

897 1326 1348 1326 Scale 2-04-5-7 5

898 1190 1241 1190 Scale 2-04-5-8 5

899 1245 1283 1245 Scale 2-04-5-9 5

900 1178 1174 1178 Scale 2-05-5-1 5

901 1271 1270 1271 Scale 2-05-5-2 5

902 1300 1313 1300 Scale 2-05-5-3 5

903 1246 1288 1246 Scale 2-05-5-4 5

904 1293 1312 1293 Scale 2-05-5-5 5

905 1201 1236 1201 Scale 2-05-5-6 5

906 1213 1222 1213 Scale 2-05-5-7 5

907 1314 1303 1314 Scale 2-05-5-8 5

908 1217 1256 1217 Scale 2-05-5-9 5

909 1236 1248 1236 Scale 246-5-1 5

910 1292 1200 1292 Scale 246-5-2 5

911 1358 1389 1358 Scale 2-06-5-3 5

912 1417 1452 1417 Scale 246-5-4 5

913 1276 1290 1276 Scale 246-5-5 5

914 1295 1310 1295 Scale 24065-6 5

915 1294 1333 1294 Scale 2-06-5-7 5

916 1262 1298 1262 Scale 2-06-5-8 5

917 1233 1237 1233 Scale 2-06-5-9 5

918 1196 1222 1196 Scale 2-07-5-1 5

919 1260 1263 1260 Scale 2-07-5-2 5

920 1189 1164 1189 Scale 2-07-5-3 5

921 1300 1288 1300 Scale 2-07-5-4 5

922 1354 1331 1354 Scale 2-07-5-5 5

923 1191 1201 1191 Scale 2-07-5-6 5

924 138 1399 1387 Scale 2-07-5-7 5

925 1345 1330 1345 Scale 2-07-5-8 5

926 1333 1324 1333 Scale 2-07-5-9 5

927 1198 1220 1198 Scale 2-08-5-1 5

928 1229 1216 1229 Scale 2-08-5-2 5

929 1296 1332 1296 Scale 2-08-5-3 5

930 1290 1308 1290 Scale 2-08-5-4 5

931 11 9C 1207 1190 Scale 2-08-5-5 5

932 11 52 11841 11 52 Scale 2-08-5-6 5

933 1258 12691 1258 Scale TOPICAL REPORT June 2003 ICUG-001, Revision 2 A-22

2-08-5-7 5

934 1170 1176 1170 Scale 2-08-5-8 5

935 1195 1202 1195 Scale 2-08-5-9 5

936 1326 1278 1326 Scale 2-09-5-1 5

937 1343 1631 1343 Scale 2-09-5-2 5

938 1242 1266 1242 Scale 2-09-5-3 5

939 1185 1222 1185 Scale 2-09-5-4 5

940 1233 1254 1233 Scale 2-09-5-5 5

941 1245 1224 1245 Scale 2-09-5-6 5

942 1215 1242 1215 Scale 2-09-5-7 5

943 1165 1245 1165 Scale 2-09-5-8 5

944 1167 1214 1167 Scale 2-09-5-9 5

945 1179 1216 1179 Scale 2-10-5-1 5

946 1278 1292 1278 Scale 2-10-5-2 5

947 1282 1295 1282 Scale 2-10-5-3 5

948 1370 1438 1370 Scale 2-10-5-4 5

949 1250 1265 1250 Scale 2-10-5-5 5

950 1269 1222 1269 Scale 2-10-5-6 5

951 1276 1278 1276 Scale 2-10-5-7 5

952 1305 1447 1305 Scale 2-10-5-8 5

953 1339 1345 1339 Scale 2-10-5-9 5

954 Frozen 1300 1300 Visal 2-11-5-1 S

955 Frozen 1237 1237 Visual 2-11-5-2 5

956 1244 1260 1244 Scale 2-11-5-3 5

957 1291 1304 1291 Scale 2-11-5-4 5

958 1351 1362 1351 Scale 2-11-5-5 5

959 1337 1382 1337 Scale 2-11-5-6 5

960 1340 1346 1340 Scale 2-11-5-7 5

961 1284 1302 1284 Scale 2-11-5-8 5

962 1274 1297 1274 Scale 2-11-5-9 5

963 1240 1270 1240 Scale 2-12-5-1 5

964 1300 1305 1300 Scale 2-12-5-2 5

965 1245 1244 1245 Scale 2-12-5-3 5

966 1 206 1219 1206 Scale 2-12-5-4 5

967 1l90 1204 1190 Scale 2-12-5-5 5

968 1140 1183 1140 Scale 2-12-5-6 5

969 1348 1427 1348 Scale 2-12-5-7 5

970 127 1249 1276 Scale 2-125-8 5

971 122 1323 1220 Scale 2-12-5-9 5

972 1177 1198 1177 Scale 2-13-5-1 5

973 Frozen 146 1467 Visual 2-13-5-2 5

974 1264 1306 1264 Scale 2-13-5-3 5

975 132 1350 1329 Scale 2-13-5-4 5

976 132 1363 1328 Scale 2-13-5-5 5

977 125 125 Scale 2-13-5-6 5

978 132 1345 1326 Scale 2-13-5-7 5

979 1 26 130 1268 Scale 2-13-5-8 5

980 1 32 1343 1324 Scale 2-13-5-9 5

981 1336 1371 1336 Scale 2-14-5-1 5

982 1120 1166 1120 Scale 2-14-5-2 5

_983 1188.

1238 1188 Scale 2-14-5-3 5

1984 118C 1246 1 1 80 Scale 2-14-5-4 5

1985 11931 1258 1 193 Scale TOPICAL REPORT ICUG-001, Revision 2 A-23 June 2003

2-14-5-5 5

986 1205l 1318 1205 Scale 2-14-5-6 5

987 1246 1246 1246 Scale 2-14-5-7 5

988 1208 1204 1208 Scale 2-14-5-8 5

989 1205 1226 _

_1205 Scale 2-14-5-9 5

990 Frozen 1233 1233 Visual 2-15-5-1 5

991 1346 1235 1346 Scale 2-15-5-2 5

992 118C 1187 1 1 80 Scale 2-15-5-3 5

993 1273 1298 1273 Scale 2-15-5-4 5

994 1265 1291 1265 Scale 2-15-5-5 5

995 1320 1361 1320 Scale 2-15-5-6 5

996 1222 1241 1222 Scale 2-15-5-7 5

997 1178 1208 1178 Scale 2-15-5-8 5

998 1176 1200 1176 Scale 2-15-5-9 5

999 1289 1289 Scale 2-16-5-1 5

1000 1211l 1205 1211 Scale 2-16-5-2 5

1001 1315 1360 1315 Scale 2-16-5-3 5

1002 1280 1314 1280 Scale 2-16-5-4 5

1003 1316 1360 1316 Scale 2-16-5-5 5

1004

__1146 111 ] Scale 2-16-5-6 1005 115 '

1194 115' Scale 2-16-5-7 1006 120 120 Scale 2-16-5-8 51007 1318 1352 1318 Scale 2-16-5-9 51008 1210 1226 12 1 Scale 2-17-5-1 51009 1209 1212 1209 Scale 2-17-5-2 51010 1224 1221 1224 Scale 2-1 7-5-3 5

11 373 1 397 71373 Scale 2-17-5-4 51012 1246 1322 1246 Scale 2-17-5-5 51013 1347 1347 Scale 2-17-5-6 51014 1144 1178 1144 Scale 2-17-5-7 51015 1140 1164 i1140 Scale 2-17-5-8 51016 1094 1183 10984 Scale 2-17-5-9 51017 1208 1228 1208 Scale 2-18-5-1 51018 108' 1191 1085 Scale 2-18-5-2 51019 1217 1252 1217 Scale 2-18-5-3 51020 1144 1208 1144 Scale 2-18-54 51021 1124 1152 1124 Scale 2-18-5-5 51022 1244 1306 1244 Scale 2-18-5-6 51023 1128 1190 1128 Scale 2-18-5-7 5

1024 1090 1090 cale 2-18-5-8 51025 1164 1247 1164 Scale 2-18-5-9 5

1026 115' 1193 1155 cale 2-19 5-1 51027 1192 1229 1192 cale 2-19-5-2 51028 l1192 1259 1192 Scale 2-19-5-3 51029 1220 1257 1220 cale 2-19-5-4 51030 1230 1261 1230 cale 2-19-5-5 51031 1230 1267 1230 cale 2-19-5-6 51032 1198 1265 1198 cale 2-19-5-7 51033 1168 1223 1168 cale 2-19-5-8 51034 1202 1238 1202 cale 2-19-5-9 51035 1130C19 1130 cale 2-20-5-1 5

1036 1245 1309 1245 cale 2-20-5-2 5

1037 1249 1311 1249 cale TOPICAL REPORT ICUG-001, Revision 2 June 2003 A-24

2-20-5-3 5

1038 1196 1226 1196 Scale 2-20-5-4 5

1039 1218 1229 1218 Scale 2-20-5-5 5

1040 1331 1370 1331 Scale 2-20-5-6 5

1041 1239 1267 1239 Scale 2-20-5-7 5

1042 1247 1257 1247 Scale 2-20-5-8 5

1043 1242 1278 1242 Scale 2-20-5-9 5

1044 1214 1477 1214 Scale 2-21-S-1 5

1045 1294 1336 1294 Scale 2-21-5-2 5

1046 1130 1130 Scale 2-21-5-3 5

1047 1246 1203 1246 Scale 2-21-54 5

1048 1150 1164 1150 Scale 2-21-5-5 5

1049 1084 1084 Scale 2-21-5-6 5

1050 1248 1301 1248 Scale 2-21-5-7 5

1051 1184 1214 1184 Scale 2-21-5-8 5

1052 1194 1205 1194 Scale 2-21-5-9 5

1053 1154 1238 1154 Scale 2-22-5-1 5

1054 1275 1275 Scale 2-22-5-2 5

1055 1336 1357 1336 Scale 2-22-5-3 5

1056 1292 1288 1292 Scale 2-22-54 5

1057 1227 1250 1227 Scale 2-22-5-5 5

1058 1235 1266 1235 Scale 2-22-5-6 5

1059 1207 1235 1207 Scale 2-22-5-7 5

1060 1365 1371 1365 Scale 2-22-5-8 5

1061 1321 1334 1321 Scale 2-22-5-9 5

1062 1255 1272 1255 Scale 2-23-5-1 5

1063 1308 1323 1308 Scale 2-23-5-2 5

1064 1368 1408 1368 Scale 2-23-5-3 5

1065 1190 1215 1190 Scale 2-23-5-4 5

1066 1217 1220 1217 Scale 2-23-S-5 5

1067 1190 1201 1190 Scale 2-23-5-6 5

1068 1192 1193 1192 Scale 2-23-5-7 5

1069 1349 1351 1349 Scale 2-23-5-8 5

1070 1307 1261 1307 Scale 2-23-5-9 5

1071 1256 1275 1256 Scale 2-24-5-1 5

1072 1130 1150 1130 Scale 2-24-5-2 5

1073 1238 1301 1238 Scale 2-24-5-3 5

1074 1205 1198 1205 Scale 2-24-54 5

1075 1260 1265 1260 Scale 2-24-5-5 5

1076 1294 1309 1294 Scale 2-24-5-6 5

1077 1252 1278 1252 Scale 2-24-5-7 5

1078 1330 1333 1330 Scale 2-24-5-8 5

1079 1176 1192 1176 Scale 2-24-5-9 5

1080 1158 1349 1158 Scale 2-01-61 6

1081 1396 1411 1396 Scale 2-01-62 6

1082 1214 1199 1214 Scale 2-01-6-3 6

1083 1239 1273 1239 Scale 2-01-64 6

1084 1268 1241 1268 Scale 2-01-65 6

1085 1213 1216 1213 Scale 2-01-66 6

1086 1338 1397 1338 Scale 2-01-67 6

1087 1093_

1147 1093 Scale 2-01-68 6

11088 1172 1253 1172 Scale 2-01-69 6

1089 877 1009 877 Scale TOPICAL REPORT ICUG-001, Revision 2 June 2003 A-25

2-0261 6

1090 968 1011 968 Scale 2-02_2 6

1091 962 959 962 Scale 2402__3 6

1092 1044 1006 1044 Scale 2402 6

1093 1144 1238 1144 Scale 2-02-6-5 6

1094 882 998 882 Scale 2402-6-6 6

1095 942 993 942 Scale 2-02_7 6

1096 1075 1119 1075 Scale 2-02_8 6

1097 1223 1264 1 1223 Scale 2-029 1098 1088 1108 1088 Scale 203 l

6 1099 1177 1177 Scale 2403-6-2 6

1100 1295 1211 1295 Scale 2403-6-3 6

1101 1200 1207 1200 Scale 2403-6-4 6

1102 1310 1307 1310 Scale 2-03-65 6

1103 1140 1109 1140 Scale 2-03-66 6

1104 1362 1316 1362 Scale 2-03-67 6

1105 1194 1125 1194 Scale 2-03-68 6

1 232 1162 1232 Scale 2-03-69 6

1107 1213 1085 1213 Scale 2-04-6-1 6

1108 1362 1362 Scale 2-04-6-2 6

1109 1214 1229 1214 Scale 2-04-63 6

1110 1169 1214 1169 Scale 2-04-64 6

1111 1211 1235 1211 Scale 2-04-65 6

1112 1268 1345 1268 Scale 2-04-66 6

1113 1175 1217 1175 Scale 2-04-6-7 6

1114 1134 1158 1134 Scale 2-04-6-8 6

1115 1145 1162 1145 Scale 2-04-6-9 6

1116 1275 1199 1275 Scale 2-05-6-1 6

1117 1248 1262 1248 Scale 2-05-62 6

1118 1174 1239 1174 Scae 2-05-63 6

1119 1184 1249 1184 Scale 2-05-64 6

1120 1171 1236 1171 Scale 2-05-65 6

1121 1218 1422 1218 Scale 2-05-66 6

1122 1143 1186 1143 Sc 2-05-6-7 6

1123 1394 1469 1 394 Scale 2-05-6-8 6

1124 1173 1244 1173 Scale 2-05-69 6

1125 1168 1166 1168 Scale 2-06-61 6

1126 1272 1269 1272 Scale 2-06-62 6

1127 1319 1335 1319 Scale 2-06-63 6

1128 1264 1 297 1 264 Scale 2-06-64 6

1129 Frozen 1358 1358 ICEMANm 2-06-6-5 6

1130 1_4_1_

3 1435 1413 Scale 2406-6-6 6

1131 1 204 1 245 1204 Scale 2-06-6-7 6

1132 1338 1366 1338 Scale 2-06-68 6

1133 1298 1318 1298 Scale 2-06-69 6

1134 1258 1258 Scale 2-07-61 6

1135 1221 1221 1221 Scale 2-07-6-2 6

1136 1183 1155 1183 Scale 2-07-6-3 6

1137 1243 1201 1243 Scale 2-07-64 6

1138 1 272 153 536 1272 Scale 2-07-65 6

1139 1236 1233 1236 Scale 2-07-66 6

1140 1250 1234 1250 Scale 2-07-67 6

1141 1282 1282 Scale TOPICAL REPORT ICUG-001, Revision 2 June 2003 A-26

2-07 6

1142 1284 1305 1284 Scale 2-07-6-9 6

1143 1186 1194 1186 Scale 2-08-6-1 6

1144 1201 1201 Scale 2-08-62 6

1145 1158 1179 1158 Scale 2-08-63 6

1146 1159 1174 1159 Scale 2-08-64 6

1147 1228 1258 1228 Scale 2-08-6-5 6

1148 1248 1255 1248 Scale 2-08-6-6 6

1149 1188 1201 1188 Scale 2-08-67 6

1150 1292 1269 1292 Scale 2-08-68 6

1151 1114 112?

1114 Scale 2-08-69 6

1152 Frozen 1108 1108 Visual 2-09-61 6

1153 1278 1278 Scale 2-09-6-2 6

1154 1350 1331 1350 Scale 2-09-6-3 6

1155 1265 1268 1265 Scale 2-09-64 6

1156 1328 1330 1328 Scale 2-09--5 6

1157 1163 1163 Scale 2-09-66 6

1158 1223 1240 1223 Scale 2-09-67 6

1159 1190 1201 1190 Scale 2-09-68 6

1160 1274 1276 1274 Scale 2-09-69 6

1161 1266 1317 1266 Scale 2-10-6-1 6

1162 1208 1088 1208 Scale 2-10-6-2 6

1163 1198 1214 1198 Scale 2-10-63 6

1164 1189 1211 1189 Scale 2-10-4 6

1165 1178 1237 1178 Scale 2-10-65 6

1166 1185 1199 1185 Scale 2-10-66 6

1167 1363 1358 1363 Scale 2-10-67 6

1168 1240 1241 1240 Scale 2-10-6-8 6

1169 1252 1254 1252 Scale 2-10-69 6

1170 Frozen 1182 1182 Visual 2-11-61 6

1171 Frozen 1345 1345 Visual 2-11-62 6

1172 1320 1339 1320 Scale 2-11 -63 6

1173 1212 1224 1212 Scale 2-11-64 6

1174 1269 1277 1269 Scale 2-11-6-5 6

1175 1288 1295 1288 Scale 2-11-6-6 6

1176 1250 1276 1250 Scale 2-11-6-7 6

1177 1206 1220 1206 Scale 2-11-6-8 6

1178 1282 1317 1282 Scale 2-11-69 6

1179 1205 1205 1205 Scale 2-12-61 6

1180 Frozen 1336 1336 Visual 2-12-62 6

1181 1225 1254 1225 Scale 2-12-6-3 6

1182 1194 1208 1194 Scale 2-12-64 6

1183 1258 1309 1258 Scale 2-12-65 6

1184 Frozen 1103 1103 Visual 2-12-6-6 6

1185 1148 1195 1148 Scale 2-12-67 6

1186 1145 1157 1145 Scale 2-12-68 6

1187 1298 1439 1298 Scale 2-12-6-9 6

1188 1328 1379 1328 Scale 2-13-6-1 6

1189 Frozen 1401 1401 Visual 2-13-62 6

1190 1302 1312 1302 Scale 2-13-6-3 6

1191 1291

_ 1340 1291 Scale 2-13-64 6

1192 11621 1236 1162 Scale 2-13-65 6

1193 11771 12071 1177 Scale TOPICAL REPORT June 2003 ICUG-001, Revision 2 A-27

2-13-66 6

1194 1259 1293 1259 Scale 2-13-6-7 6

1195 1256 1253 1256 Scale 2-13-6-8 6

1196 1281 1317 1281 Scale 2-13-6-9 6

1197 1326 1353 1326 Scale 2-14-61 6

1198 11

_ 1163_1181 Scale 2-14-6-2 6

1199 1138 1236 1138 Scale 2-14-63 6

1200 1138 1148 1138 Scale 2-14-64 6

1201 1178 1253 1178 Scale 2-14-65 6

1202 1274 1274 Scale 2-14-6-6 6

1203 1280 1280 Scale 2-14-6-7 6

1204 Frozen 1194 1194 ICEMAN 2-14-68 6

1205 1190 1218 1190 Scale 2-14&9 6

1206 Frozen 19191ICEMANm 2-14-6-9 6

X 1207 1220 1234 1220 Scale 2-156 2 6

1208 1167 1237 1167 Scale 2-156 3 6

1209 1327 1350 1327 Scale 2-15-6-4 6

1210 1318 1331 1318 Scale 2-15-6-5 6

1211 1168 1236 1168 Scale 2-15_6 6

1212 1253 1280 1253 Scale 2-15_7 1213 1206 1303 1206 Scale 2-15-&8 6

1214 1295 1309 1295 Scale 2-15-69 6

1215 1188 1211 1_18 8 Scale 2-16-61 6

1216 1221 1272 1221 Scale 2-16-6-2 6

1217 1193 1215 1193 Scale 2-16-6-3 6

1218 1196 1245 1196 Scale 2-16 6

1219 1161 1238 1161 Scale 2-16&5 6

1220 111 1112 Scale 2-16 6 6

1221 1155 1213 11S5 Scale 2-166 7 6

1222 1134 1167 1134 Scale 2-16-6-8 6

1223 1348 1372 1348 Scale 2-16-6-9 6

1224 1341 1258 1341 Scale 2-176 1 6

1225 1349 1403 1349 Scale 2-17_2 6

1226 1326 1316 1326 Scale 2-17-63 61227

__1165 1181 1165 Scale 2-17-64 6

1228 1262 1298 1262 Scale 2-17-65 6

1229 1134 1139 1134 Scale 2-17-6-6 6

1230 1204 1239 1204 Scale 2-17-6-7 6

1231 1184 1243 1184 Scale 2-178 6

1232 1106 1113 1106 Scale 2-179 1233 1150 1160 1150 Scale 2-1861 6

1234 1149 1200 1149 Scale 2-18_2 6

1235 1266 1322 1266 Scale 2-18-6-3 6

1236 1240 1229 1240 Scale 2-1864 6

1237 1314 1265 1314 Scale 2-185 6

1238 1284 1321 1284 Scale 2-___6_6 1239 1139 1179 1139 Scale 2-18-67 61240 1188 1240 1188 Scale 2-18-68 6

1241 1146 1178 1146 Scale 2-18-6-9 6

1242 1033 1211 1033 Scale 2-19-6-1 61243 1127 1143 1127 Scale 2-19-6-2 6

1244 1230 1289 1230 Scale 2-19-63 6

1245 1285 1334 1285 Scale TOPICAL REPORT June 2003 ICUG-001, Revision 2 A-28

2-19-6-4 6

1246 1196 1240 1196 Scale 2-19-65 6

1247 l1190 1190 Scale 2-19-66 6

1248 1184 118 1184 Scale 2-19-6-7 6

1249 1182 123 1182 Scale 2-19-6-8 6

1250 1170 1222 1170 Scale 2-19-6-9 6

1251 1166 1197 1166 Scale 2-20-6-1 6

1252 1203 1247 1203 Scale 2-20-62 6

1253 1194 124?

1194 Scale 2-20-63 6

1254 1339 1468 1339 Scale 2-20-64 6

1255 1180 1205 1 1 8 Scale 2-20-65 6

1256 1149 1175 1149 Scale 2-20-6-6 6

1257 1282 1365 1282 Scale 2-20-6-7 6

1258 1192 1212 1192 Sale 2-20-6-8 6

1259 1162 1119 116 Sale 2-20-6-9 6

1260 1118 18 O

111 Sale 2-21-61 6

1261 1187 1238 118 Sale 2-21-6-2 6

1262 1146 1136 1146 Scale 2-21-63 6

1263 1144 1225 1144 Sale 2-21-64 6

1264 1080 1152 1080 Scale 2-21__5 6

1265 1161 116 Scale 2-21-6-3 6

1266 1168 120:

1168 Scale 2-21-6-7 1267 CI

,o 118' l 1 Sale 2-216-5 6

1268 1081 1148 1081 Sale 2-216-9 6

1269 1106 1130 1106 Scale 2-22-67 6

1270 1205 1217 1205 Scale 2-22-6-2 6

1271 1304 1306 1304 Scale 2-22-6-3 6

1272 1312 1388 1312 Sale 2-22-6-4 6

1273 1342 1337 134 Sale 2-22-6-5 6

1274 1312 1315' 1312 Scale 2-22-6 6

1275 1225 122 1225 Scale 2-226-7 6

1276 1380 136;2 138tl Scale 2-226-8 6

1277 1283 1304 1283 Sale 2-226-9 6

1278 1240 1252 1240 Scale 2-23 6

1279 1170 1196 117 Sale 2-23-62 6

1280 119212 1182 Scale 2-23-6-3 6

1281 1254 1286 125 Sale 2-23-6-4 6

1282 1221 1245 1221 Scale 2-236-5 6

1283 1316 1314 1316 Scale 2-236 6

1284 1249 1261 124 Sale 2-23&7 6

1285 1152 1153 1152 Scale 2-2368 61286 1194 1240 1194 Sale 2-23&9 61287 1191 1182 1 19 Sale 2-24-6-1 61288 1125 1114 1125 Sale 2-24&2 61289 1184 1154 1184 Scale 2-24-6-3 6

1290 1159 1169 1159 Scale 2-24

__6 1291 Frozen 1209 1209 ICEMANTM 2-24__5 6

1292

___Frozen 118 l

1198 ICEMANTM 2-246-66 1293 1242 1288 124 Sale 2-24-6-7 61294 1230 1274 123 Sale 2-24-6-8 6

1295 1168 1210 1168 Scale 2-24_9 6_1296 1168 1188 1168 Scale 2-01-7-1 7

1297 109t8 1111 1098ISeale TOPICAL REPORT ICUG-001, Revision 2 A-29 June 2003

2-01-7-2 7

1298 1273 1239 1273 Scale 2-01-7-3 7

1299 1194 1160 1194 Scale 2-01-7-4 7

1300 1263 1211 1263 Scale 2-01-7-5 7

1301 1311 1308 1311 Scale 2-01-7-6 7

1302 1154 1166 1154 Scale 2-01-7-7 7

1303 1104 1076 1104 Scale 2-01-7-8 7

1304 1162 1248 1162 Scale 2-01-7-9 7

1305 733 880 733 Scale 2-02-7-1 7

1306 940 907 940 Scale 2-02-7-2 7

1307 1059 1072 1059 Scale 2-02-7-3 7

1308 954 973 954 Scale 2-02-74 7

1309 978 1002 978 Scale 2-02-7-5 7

1310 1105 1103 1105 Scale 2-02-7-6 7

1311 994 1057 994 Scale 2-02-7-7 7

1312 993 1048

_993 Scale 2-02-7-8 7

1313 866 964 866 Scale 2-02-7-9 7

1314 1129 1134 1129 Scale 2-03-7-1 7

1315 Frozen 1021 1021 Visual 2-03-7-2 7

1316 Frozen 956 956 Visual 2-03-7-3 7

1317 1391 1378 1391 Scale 2-03-74 7

1318 1218 1218 Scale 2-03-7-5 7

1319 1238 1234 1238 Scale 2-03-7-6 7

1320 1197 1192 1197 Scale 2-03-7-7 7

1321 1289 1233 1289 Scale 2-03-7-8 7

1322 1220 1208 1220 Scale 2-03-7-9 7

1323 1130 1100 1130 Scale 2-04-7-1 7

1324 1434 1405 1434 Scale 2-04-7-2 7

1325 1284 1333 1284 Scale 2-04-7-3 7

1326 1278 1300 1278 Scale 2-04-74 7

1327 Frozen 1201 1201 Visual 2-04-7-5 7

1328 1270 1102 1270 Scale 2-04-7-6 7

1329 Frozen 1200 1200 ICEMANTm 2-04-7-7 7

1330 Frozen 1080 1080 Visual 2-04-7-8 7

1331 1159 1167 1159 Scale 2-04-7-9 7

1332 1278 1315 1278 Scale 2-05-7-1 7

1333 1296 1282 1296 Scale 2-05-7-2 7

1334 1183 1200 1183 Scale 2-05-7-3 7

1335 1233 1233 Scale 2-05-7_4 7

1336 Frozen 1344 1344 Visual 2-05-7-5 7

1337 Frozen 1261 1261 Visual 2-05-7-6 7

1338 1322 1421 1322 Scale 2-05-7-7 7

1339 1204 1239 1204 Scale 2-05-7-8 7

1340 1276 1282 1276 Scale 2-05-7-9 7

1341 Frozen 1301 1301 Visual 2-06 1 7

1342 Frozen 1277 1277 Visual 24_7-2 7

1343 Frozen 1038 1038 Visual 2467-3 7

1344 Frozen 1052 1052 Visual 20_7-4 7

1345 Frozen 1196 1196 Visual 20_7-5 7

1346 Frozen 1258 1258 Visual 2-06-7-6 7

1347 Frozen 1393 1393 Visual 2-06-7-7 7

1348 Frozen 1256 1256 Visual 2-06-7-8 7

1349 Frozen 1387 1387 Visual TOPICAL REPORT ICUG-001, Revision 2 June 2003 A-30

2-06-7-9 7

1350 Frozenl 1011 1011 Visual 2-07-7-1 7

1351 Froen 1053 1053 Visual 2-07-7-2 7

1352 1159 1144 1159 Scale 2-07-7-3 7

1353 1127 1158 1127 Scale 2-07-7-4 7

1354 1187 1185 1187 Scale 2-07-7-5 7

1355 1175 1175 Scale 2-07-7-6 7

1356 1176 1192 1176 Sale 2-07-7-7 7

1357 1196 1231 1196 Sale 2-07-7-8 7

1358 1104 1126 1104 Scale 2-07-7-9 7

1359 1121 1 121 Sale 2-08-7-1 7

1360 1174 1238 1174 Sale 2-08-7-2 7

1361 1230 1230 Scale 2-08-7-3 7

1362 1224 1224 Scale 2-08-7-4 7

1363 1128 1128 Sale 2-08-7-5 7

1364 Frozen 126 1267 1267 Visual 2-08-7-6 7

1365 1184 1194 1184 Scale 2-08-7-7 7

1366 Frozen 1236 1236 ICEMANTm 2-08-7-8 7

1367 Frozen 144' 1445 Visual 2-08-7-9 7

1368 Frozen ____

1278 1278 Visual 2-09-7-1 7

1369 Frozen 1254 1254 Visual 2-09-7-2 7

1370 Frozen 1143 1143 Visual 2-09-7-3 7

1371 1193 1534 1193 Scale 2-09-7-4 7

1372 1238 1210 1238 Scale 2-09-7-5 7

1373 Frozen 1234 1234 Visual 2-09-7-6 7

1374 1241 1267 1241 Scale 2-09-7-7 7

1375 1151 1194 1151 Scale 2-09-7-8 7

1376 118C 1201 1180 Scale 2-09-7-9 7

1377 1241 1280 1241 Scale 2-10-7-1 7

1378 Frozer 1267 1267 Visual 2-10-7-2 7

1379 1047 101 1047 Scale 2-10-7-3 7

1380 1268 1308 1268 Scale 2-10-7-4 7

1381 117 1194 1176 Scale 2-10-7-5 7

1382 Frozen 1247 1247 Visual 2-10-7-6 7

1383 1349 1346 1349 Scale 2-10-7-7 7

1384 Frozen 1411 1411 ICEMAN'hI 2-10-7-8 7

1385 Frozen 1440 1440 ICEMANTm 2-10-7-9 7

1386 Frozen 1300 1300 Visual 2-11-7-1 7

1387 Frozen 1355 1355 Visual 2-11-7-2 7

1388 1359 1304 1359 Scale 2-11-7-3 7

1389 1285 1338 1285 Scale 2-11-7-4 7

1390 1411 1395 1411 Scale 2-11-7-5 7

1391 Frozen 1133 1133 Visual 2-11-7-6 7

1392 1192 1225 1192 Scale 2-11-7-7 7

1393 1209 1225 1209 Scale 2-11-7-8 7

1394 1330 1333 1330 Scale 2-11-7-9 7

1395 1135 1135 Scale 2-12-7-1 7

1396 Frozen 1378 1378 Visual 2-12-7-2 7

1397 Frozen 1267 1267 Visual 2-12-7-3 7

1398 Frozen 1345 1345 Visual 2-12-7-4 7

1399 Frozen _

1356 1356 Visual 2-12-7-5 7

1400 Frozen 1376 1376 ICEMANTm 2-12-7-6 7

1401 1119

1214, 1119 Scale TOPICAL REPORT ICUG-001, Revision 2 A-31 June 2003

2-12-7-7 7

1402 1310 1403 1310 Scale 2-12-7-8 7

1403 1116 1165 1116 Scale 2-12-7-9 7

1404 Frozen 1145 1145 Visual 2-13-7-1 7

1405 Frozen 1276 1276 Visual 2-13-7-2 7

1406 Frozen 1231 1231 Visual 2-13-7-3 7

1407 1253 1291 1253 Scale 2-13-7-4 7

1408 1229 1242 1229 Scale 2-13-7-5 7

1409 Frozen 1356 1356 Visual 2-13-7-6 7

1410 Frozen _

1388 1388 Visual 2-13-7-7 7

1411 Frozen 1230 1230 Visual 2-13-7-8 7

1412 Frozen 1079 1079 Visual 2-13-7-9 7

1413 Frozen 1256 1256 Visual 2-14-7-1 7

1414 1178 1237 1178 Scale 2-14-7-2 7

1415 1138 1205 1138 Scale 2-14-7-3 7

1416 Frozen 1046 1046 Visual 2-14-7-4 7

1417 Frozen 1136 1136 Visual 2-14-7-5 7

1418 Frozen 1262 1262 Visual 2-14-7-6 7

1419 Frozen 1323 1323 ICEMANTm 2-14-7-7 7

1420 Frozen 1156 1156 ICEMANTm 2-14-7-8 7

1421 Frozen 1739 1739 ICEMANTm 2-14-7-9 7

1422 Frozen 1473 1473 Visual 2-15-7-1 7

1423 1227 1222 1227 Scale 2-15-7-2 7

1424 Frozen 1104 1104 Visual 2-15-7-3 7

1425 Frozen 1069 1069 Visual 2-15-74 7

1426 Frozen 1009 1009 Visual 2-15-7-5 7

1427 Frozen 1378 1378 Visual 2-15-7-6 7

1428 Frozen 1405 1405 Visual 2-15-7-7 7

1429 1168 1181 1168 Scale 2-15-7-8 7

1430 1146 1211 1146 Scale 2-15-7-9 7

1431 1158 1199 1158 Scale 2-16-7-1 7

1432 1182 1229 1182 Scale 2-16-7-2 7

1433 1182 1320 1182 Scale 2-16-7-3 7

1434 1068 1115 1068 Scale 2-16-74 7

1435 1204 1230 1204 Scale 2-16-7-5 7

1436 Frozen 1172 1172 Visual 2-16-7-6 7

1437 Frozen 1054 1054 Visual 2-16-7-7 7

1438 Frozen 1191 1191 ICEMANTm 2-16-7-8 7

1439 1153 1308 1153 Scale 2-16-7-9 7

1440 Frozen 1132 1132 Visual 2-17-7-1 7

1441 Frozen 1167 1167 Visual 2-17-7-2 7

1442 Frozen 1255 1255 ICEMANm 2-17-7-3 7

1443 1356 1371 1356 Scale 2-17-74 7

1444 1323 1312 1323 Scale 2-17-7-5 7

1445 Frozen 1321 1321 Visual 2-17-7-6 7

1446 1151 1151 Scale 2-17-7-7 7

1447 1222 1253 1222 Scale 2-17-7-8 7

1448 1303 1274 1303 Scale 2-17-7-9 7

1449 1040 1072 1040 Scale 2-18-7-1 7

1450 Frozen 1256 1256 Visual 2-18-7-2 7

1451 1180 1172 1180 Scale 2-18-7-3 7

1452 1331 1236 1331 Scale 2-18-74 7

1453 1011 10541 1011 Scale TOPICAL REPORT ICUG-001, Revision 2 A-32 June 2003

2-18-7-5 7

1454 1129 1129 Scale 2-18-7-6 7

1455 1096 1158 1096 Scale 2-18-7-7 7

1456 1335 1363 1335 Scale 2-18-7-8 7

1457 1198 1246 1198 Scale 2-18-7-9 7

1458 Frozen 1359 1359 Visual 2-19-7-1 7

1459 932 932 Scale 2-19-7-2 7

1460 1115 1165 1115 Scale 2-19-7-3 7

1461 1180 1211 1180 Scale 2-19-7-4 7

1462 1202 1219 1202 Scale 2-19-7-5 7

1463 1163 1213 1163 Scale 2-19-7-6 7

1464 1118 1123 1 1 18 Scale 2-19-7-7 7

1465 Frozen 1134 1134 Visual 2-19-7-8 7

1466 Frozen 1209 1209 Visual 2-19-7-9 7

1467 Frozen 1128 1128 Visual 2-20-7-1 7

1468 1117 1152 1_1_17 Scale 2-20-7-2 7

1469 1175 1177 1175 Scale 2-20-7-3 7

1470 1265 1331 1265 Scale 2-20-7-4 7

1471 954 990 954 Scale 2-20-7-5 7

1472 1132 1132 Scale 2-20-7-6 7

1473 1259 1228 1259 Scale 2-20-7-7 7

1474 914 1073 914 Scale 2-20-7-8 7

1475 1143 1194 1143 Scale 2-20-7-9 7

1476 1028 1028 Scale 2-21-7-1 7

1477 1070 1070 Scale 2-21-7-2 7

1478 1133 1081 1133 Scale 2-21-7-3 7

1479 1165 1230 1165 Scale 2-21-7-4 7

1480 1148 1224 1148 Scale 2-21-7-5 7

1481 1141 1141 Scale 2-21-7-6 7

1482 1218 1311 1218 Scale 2-21-7-7 7

1483 1228 1259 1228 Scale 2-21-7-8 7

1484 1093 1141 1093 Scale 2-21-7-9 7

1485 1007 1046 1070 1007 Scale 2-22-7-1 7

1486 1140 1155 1140 Scale 2-22-7-2 7

1487 1216 1216 Scale 2-22-7-3 7

1488 1412 1304 1412 Scale 2-22-7-4 7

1489 1243 1247 1243 Scale 2-22-7-5 7

1490 Frozen 1383 1383 Visual 2-22-7-6 7

1491 1325 1325 Scale 2-22-7-7 7

1492 1345 1367 1345 Scale 2-22-7-8 7

1493 Frozen 1034 1034 Visual 2-22-7-9 7

1494 1055 1035 Scale 2-23-7-1 7

1495 1100 1166 1100 Scale 2-23-7-2 7

1496 1145 1182 1145 Scale 2-23-7-3 7

1497 1294 1399 1294 Scale 2-23-7-4 7

1498 1284 1274 1284 Scale 2-23-7-5 7

1499 1200 1219 1200 Scale 2-23-7-6 7

1500 1270 1260 1270 Scale 2-23-7-7 7

1501 1212 1215 1212 Scale 2-23-7-8 7

1502 1295 1306 1295 Scale 2-23-7-9 7

1503 1185 1062 1185 Scale 2-24-7-1 7

1504 972 1002 972 Scale 2-24-7-2 7

1505 1096 1148 1096 Scale TOPICAL REPORT ICUG-001, Revision 2 A-33 June 2003

2-24-7-3 7

1506 1130 1119 1130 Scale 2-24-7-4 7

1507 1189 1223 1189 Scale 2-24-7-5 7

1508 Frozen 1289 1289 Visual 2-24-7-6 7

1509 1249 1312 1249 Scale 2-24-7-7 7

1510 1292 1314 1292 Scale 2-24-7-8 7

1511 1192 1216 1192 Scale 2-24-7-9 7

1512 Frozen 1147 114 Visual 2-01-8-1 8

1513 Frozen 1131 1131 Visual 2-01-8-2 8

1514 Frozen 1429 1429 Visual 2-01-8-3 8

1515 Frozen 1322 1322 Visual 2-01-8-4 8

1516 Frozen 1429 1429 V 2-01-8-5 8

1517 Frozen 1333 1333 Visual 2-01-8-6 8

1518 Frozen 1536 1536 Visual 2-01-8-7 8

1519 1090 1124 1141 1090 Scale 2-01-8-8 8

1520 770 764 1120 770 Scale 2-01-8-9 8

1521 853 843 1098 853 Scale 2-02-8-1 8

1522 995 1261 995 Scale 2-02-8-2 8

1523 858 85_ Scale 2-02-8-3 8

1524 1067 1096 1216 1067 Scale 2-02-8-4 8

1525 866 1034 866 Scale 2-02-8-5 8

1526 1058 1039 1058 Scale 2-02-8-6 8

1527 946 1205 946 Scale 2-02-8-7 8

1528 838 1082 838 Scale 2-02-8-8 8

1529 1165 1536 1165 Scale 2-02-8-9 8

1530 1026 1141 1026 Scale 2-03-8-1 8

1531 Frozen 1045 1045 Visual 2-03-8-2 8

1532 Frozen 1072 1072 Visual 2-03-8-3 8

1533 Frozen 1429 1429 Visual 2-03-8-4 8

1534 Frozen 1034 1034 Visual 2-03-8-5 8

15S35 Frozen 901 901 Visual 2-03-8-6 8

1536 Frozen 904 904 Visual 2-03-8-7 8

1537 1148 1077 1205 1148 Scale 2-03-8-8 8

1538 1314 1284 1360 1314 Scale 243-8-9 8

1539 l lOC 1370 10C Scale 2-04-8-1 8

1540 Frozen 1429 1429 Visual 2-04-8-2 8

1541 1381 1386 1381 Scale 2-04-8-3 8

1542 Frozen 1109 1109 Visual 2-04-8-4 8

1543 Frozen 1312 1312 Visual 2-04-8-5 8

1544 Frozen l O 1008 Visual 2-044-8-6 8

1545 Frozen 1205 1205 Visual 2-04-8-7 8

1546 Frozen 1098 1098 Visual 2-04-8-8 8

1547 Frozen 1322 1322 Visual 2-04-8-9 8

1548 Frozen 984 984 Visual 2-05-8-1 8

1549 Frozen 999 999 Visual 2-05-8-2 8

1550 Frozen 1157 1157 Visual 2-05-8-3 8_1551 Frozen 1083 1083 Visual 205-8-4 8

1552 Frozen 1038 1038 Visual 2-05-8-5 8

1553 Frozen 1215 1215 Visual 2-05-8-6 8

1554 Frozen 928 928 Visual 2-05-8-7 8

1555 Frozen 928 928 Visual 2-05-8-8 8

11556 Frozen 923 923 Visual 2-05-8-9 8

1557 Frozen l lOS 1109 Visual TOPICAL REPORT June 2003 ICUG-001, Revision 2 A-34

2-06-8-1 8

1558 Frozen 1170 1170 Visual 2-06-8-2 8

1559 Frozen 1072 1072 Visual 2-06-8-3 8

1560 Frozen 1180 11 80 Visual 24068-4 8

1561 Frozen 1207 1207 Visual 2-06-8-5 8

1562 Frozen 1287 1287 Visual 2-06-8-6 8

1563 Frozen 1188 1188 Visual 2-06-8-7 8

1564 Frozen 1287 1287 Visual 246-8-8 8

1565 1382 1264 1382 Scale 2-06-8-9 8

1566 Frozen 989 989 Visual 2-07-8-1 8

1567 Frozen 956 956 Visual 2-07-8-2 8

1568 Frozen 1000 1000 Visual 2-07-8-3 8 _

1569 1321 1344 1418 1321 Scale 2-07-8-4 8

1570 Frozen 821 82l Visual 2-07-8-5 8

1571 Frozen 1358 1358 Visual 2-07-8-6 8

1572 Frozen 1386 1386 Visual 2-07-8-7 8

1573 1219 1286 1372 1219 Scale 2-07-8-8 8

1574 1254 1349 1384 1254 Scale 2-07-8-9 8

1575 1035 1075 1035 Scale 2-08-8-1 8

1576 Frozen 1281 1281 Visual 2-08-8-2 8

1577 Frozen 1434 1434 Visual 2-08-8-3 8

1578 Frozen 1483 1483 Visual 2-08-8-4 8

1579 Frozen 1081 1081 Visual 2-08-8-5 8

1580 Frozen 1254 1254 Visual 2-08-8-6 8

1581 Frozen 1289 1289 Visual 2-08-8-7 8

1582 Frozen 1173 1173 Visual 2-08-8-8 8

1583 Frozen 1536 1536 Visual 2-08-8-9 8

1584 Frozen 1115 1115 Visual 2-09-8-1 8

1585 Frozen 1330 1330 Visual 2-09-8-2 8

1586 Frozen 1250 1250 Visual 2-09-8-3 8

1587 Frozen 1192 1192 Visual 2-09-8-4 8

1588 1219 1116 1219 Scale 2-09-8-5 8

1589 Frozen 1416 1416 Visual 2-09-8-6 8

1590 Frozen 1383 1383 Visual 2-09-8-7 8

1591 Frozen 1156 1156 Visual 2-09-8-8 8

1592 Frozen 1098 1098 Visual 2-09-8-9 8

1593 Frozen 1123 1123 Visual 2-10-8-1 8

1594 1240 1359 1409 1240 Scale 2-10-8-2 8

1595 1115 1237 1251 1115 Scale 2-10-8-3 8

1596 1115 1268 1274 111 5 Scale 2-10-8-4 8

1597 1092 1131 1288 1092 Scale 2-10-8-5 8

1598 Frozen 1216 1216 Visual 2-10-8-6 8

1599 1143 1249 1293 1143 Scale 2-10-8-7 8

1600 Frozen 1317 1317 Visual 2-10-8-8 8

1601 Frozen 1377 1377 Visual 2-10-8-9 8

1602 Frozen 1284 1284 Visual 2-11-8-1 8

1603 Frozen 1381 1381 Visual 2-11-8-2 8

1604 Frozen 1497 1497 Visual 2-11-8-3 8

1605 Frozen 1327 1327 Visual 2-11-8-4 8

1606

Frozen, 1376 1376 Visual 2-11-8-5 8

1607 Frozen 1376 1376 Visual 2-11-8-6 8

1608 Frozen 1367 1367 Visual 2-11-8-7 8

1609 Froze 1345 1345 Visual TOPICAL REPORT ICUG-001, Revision 2 June 2003 A-35

2-11-8-8 8

1610 Frozen 1320 1320 Visual 2-11-8-9 8

1611 1086 1171 1216 1086 Scale 2-12-8-1 8

1612 Frozen 1323 1323 Visual 2-12-8-2 8

1613 Frozen 1416 1416 Visual 2-12-8-3 8

1614 Frozen 1418 1418 Visual 2-12-8-4 8

1615 Frozen 1340 1340 Visual 2-12-8-5 8

1616 Frozen 1394 1394 Visual 2-12-8-6 8

1617 Frozen 1447 1447 Visual 2-12-8-7 8

1618 1106 1186 1109 1106 Scale 2-12-8-8 8

1619 Frozen 1315 1315 Visual 2-12-8-9 8

1620 Frozen 1349 1349 Visual 2-13-8-1 8

1621 Frozen 1309 1309 Visual 2-13-8-2 8

1622 Frozen 1193 1193 Visual 2-13-8-3 8

1623 Frozen 1232 1232 Visual 2-13-8-4 8

1624 1159 1271 1189 159 Scale 2-13-8-5 8

1625 Frozen 1362 1362 Visual 2-13-8-6 8

1626 Frozen 1367 1367 Visual 2-13-8-7 8

1627 Frozen 1357 1357 Visual 2-13-8-8 8

1628 Frozen 1465 1465 Visual 2-13-8-9 8

1629 Frozen 1422 1422 Visual 2-14-8-1 8

1630 Frozen 1202 1202 Visual 2-14-8-2 8

1631 1350 1329 1309 1350 Scale 2-14-8-3 8

1632 Frozen 1199 1199 Visual 2-14-8-4 8

1633 Frozen 1161 1161 Visual 2-14-8-5 8

1634 Frozen 1181 1181 Visual 2-14-8-6 8

1635 Frozen 1411 1411 Visual 2-14-8-7 8

1636 1330 1478 1388 1330 Scale 2-14-8-8 8

1637 Frozen 1153 11S3 Visual 2-14-8-9 8

1638 Frozen 1296 1296 Visual 2-15-8-1 8

1639 Frozen 1159 1159 Visll 2-15-8-2 8

1640 Frozen 1477 1477 Visual 2-15-8-3 8

1641 Frozen 1158 1158 Visual 2-15-8-4 8

1642 Frozen 1117___

17

__Visual 2-15-8-5 8

1643 Frozen 1102 1102 Visual 2-15-8-6 1644 Frozen 1127 1127 Visual 2-15-8-7 8

1645 Frozen 1260 1260 Visual 2-15-8-8 8

1646 l1lS6 1257 1242i15 6 Scale 2-15-8-9 8

1647 Frozen 1167_

1167 Visual 2-16-8-1 8

1648 Frozen 1191 1191 Visual 2-16-8-2 8

1649 Frozen 1376 1376 Visual 2-16-8-3 8

1650 1202 1176 1189 1202 Scale 2-16-8-4 8

1651 Frozen 1143 1143 Visual 2-16-8-5 8

1652 Frozen 1253 1253 Visual 2-16-8-6 8

1653 Frozen 1367 1367 Visual 2-16-8-7 8

1654 Frozen 1132 1132 Visual 2-16-8-8 8

1655 Frozen 1181 1181 Visual 2-16-8-9 8

1656 Frozen 989 989 Visual 2-17-8-1 8

1657 Frozen 1322 1322 Visial 2-17-8-2 8

1658 Frozen 1408 140 Visual 2-17-8-3 8

1659 Froze 110 110 Visual 2-17-84 8

1660 Frozen 1378 1378 Visual 2-17-8-5 8

1661 Frozen 803 803 Visual TOPICAL REPORT ICUG-001, Revision 2 June 2003 A-36

2-17-8-6 8

1662 Frozen 1363 1363 Visualj 2-17-8-7 8

1663 1086 1108 1196 1086 Scale 2-17-8-8 8

1664 Frozen 1406 1406 Visual 2-17-8-9 8

1665 1202

_1411 120 Scale 2-18-8-1 8

1666 1076 1221 1076 Scale 2-18-8-2 8

1667 Frozen 1397 1397 Visual 2-18-8-3 8_1668 1140 1208 1140 Scale 2-18-8-4 8

1669 1286 1314 1359 1286 Scale 2-18-8-5 8

1670 Frozen 1058 Visual 2-18-8-6 8_1671 Frozen 1274 1274 Visual 2-18-8-7 8

1672 Frozen 1261 1261 Visual 2-18-8-8 8

1673 Frozen 1044 1044 Visual 2-18-8-9 8

1674 Frozen 101 Cl 101t Visual 2-19-8-1 8

1675 1130 1259 1370 1130 Scale 2-19-8-2 8

1676 Frozen 1319 1319 Visual 2-19-8-3 8

1677 Frozen 1223 1223 Visual 2-19-8-4 8

1678 Frozen 1131 1131 Vsual 2-19-8-5 8

1679 Frozen 1184 1184 Visual 2-19-8-6 8

1680 Frozen 1487 1487 Visual 2-19-8-7 8

1681 Frozen l1004 1004 Visual 2-19-8-8 8

1682 Frozen 994 994 Visual 2-19-8-9 8

1683 Frozen 1221 1221 Visual 2-20-8-1 8

1684 Frozen 1192 1192 Visual 2-20-8-2 8

1685 Frozen 1231 1210 1231 ICEMANTm4 2-20-8-3 8

1686 1275 1311 1377 1275 Scale 2-20-8-4 8

1687 1186 1194 1219 1186 Scale 2-20-8-5S 1688 1071 1177 1073 1071 Scale 2-20_8-6 8

1689 1323 1010 1438 1323 Scale 2-20-8-7 8

1690 1126 1164 1274 1126 Scale 2-20-8-8 8

1691 772 817 817 772 Scale 2-20-8-9 1692 972 971 1447 972 Scale 2-21-8-1

__1693 Frozen 862 862 Visual 2-21-8-2 1694 1062 1189 1369 1062 Scale 2-21-8-3 1695 1181 1294 1288 1181 Scale 2-21-8-4 1696 Frozen 992 992 Visual 2-21-8-5 8

1697 Frozen 1154 1154 Visual 2-21-8-6 1698 Frozen 1093 1093 Visual 2-21 7 81699 Frozen 1207 1207 Visual 2-21-8-8 8

1700 Frozen 1409 1409 Visual 2-21-8-9 8

1701 Frozen 1137 1137 Visual 2-22-8-1 1702 Frozenr144 1448 144_ Visual 2-22-8-2 8

1703 1200 1216 1068 1200 Scale 2-22-8-3 a

1704 1465 1524 1296 1465 Scale 2-22-8-4 8

1705 Frozen 1269 1269 Visual 2-22-8-5 8

1706 Frozen 1483 1483 Visual 2-22-8-6 8

1707 Frozen 1225 1225 Visual 2-22-8-7 8

1708 Frozen 1244 1075 1244 ICEMAN 2-22-8-8 8

1709 1449 1391 1487 1449 Scale 2-22-8-9 8

1710 Frozen 1216 1216t Visual 2-23-8-1 1711 Frozen 1487 1487 Visual 2-23-8-2 1712 Frozen 1085 1085 Visual 2-23 3

_1713 Frozen 1225 1225 Visusal TOPICAL REPORT June 2003 ICUG-001, Revision 2 A-37

2-23-8-4 8

1714 l

Frozenl l

1166 1166 Visual 2-23-8-5 8

1715 1495 42 1417 1495 Scale 2-23-8-6 8

1716 1236 1253 1324 1236 Scale 2-23-8-7 8

1717 1284 1273 1317 1284 Scale 2-23-8-8 8

1718 Frozen 1178 1178 Visual 2-23-8-9 8

1719 Frozen 1016 1016 Visual 2-24-8-1 8

1720 894 1267 1116 894 Scale 2-24-8-2 8

1721 1112 1238 1 1 12 Scale 2-24-8-3 8

1722 1116 1169 1254 116 t Scale 2-24-8-4 8

1723 Frozen 1089 1089 Visual 2-24-8-5 8

1724 Frozen 1292 1292 Visual 2-24-8-6 8

1725 Frozen 1135 1135 Visual 2-24-8-7 8

1726 Frozen 1231 1231 Visual 2-24-8-8 8

1727 Frozen 1406 1406 Visual 2-24-8-9 1728 Frozen 1250 1250 Visual 2-01-9-1 9

1729 Frozen 1056 1056 Visual 2-01-9-2 9

1730 Frozen 15 36 153 Visual 2-01-9-3 9

1731 Frozen 1536 153 Visual 2-01-9-4 9

1732 Frozen 1536 1536 Visual 2-01-9-5 9

1733 Frozen 1322 1322 Visual 2-01-9-6 9

1734 Frozen 704 704 Visiial 2-01-9-7 9

1735 Frozen 986 986 Visual 2-01-9-8 9

17365 86 11 74 856 Scale 2-01-9-9 9

1737 828 1114 688 828 Scale 2-02-9-1 9

1738 Frozen 1037 103 Visual 2-02-9-2 9

1739 Frzen 1376 1376 Visual 2-02-9-3 9

1740 Frozen 1104 1104 Visual 2-02-9-4 9

1741 Frozen 1333 1333 Visual 2-02-9-5 9

1742 Frozen 840 840 Visual 2-02-9-6 9

1743 Frozen 93 8 93 Visual 2-02-9-7 9

1744 Frozen 880 880 Visual 2-02-9-8 9

1745 Frozen 1451 1451 Visual 2-02-9-9 9

1746 Frzen 1072 1072 Visual 2403-9-1 9

1747 Frozen 1139 1139 Visual 2-03-9-2 9

1748 Frozen 1078 1 078 Visu 2-03-9-3 9

1749 Frozen 1232 1232 Visual 2-03-9-4 9

1750 Frozen 1370 1370 Visual 2-03-9-9 9

1751 Frozen 1345 1345 Visual 2-03-9-6 9

1752 Frozen 1464 1464 Visual 2-03-9-7 9

1763 Frozen 1376 X

1376 Visual 2403-9-8 9

1764 Frozen 1178 1178 Visual 2-03 99 9

1763 Frozen 1298 1298 Visual 249-1 9

1756 Frozen 1370 1370V isual 2-04-9-2 91757 1230 1333 1230 Scale 2-04-9-3 9

1758 Frozen 1226 1226 Visual 2404-9-4 91759 Frozen 11l95 1195 Visual 2-04-9-5 9

1760 Frozen 111o 1

Visual 2404-9-6 91761 Frozen.1216 1216 Visual 24-9-7 1762 Frozen 1024 1024 Visual 24-9-8 191763

Frozen, 114 1 114I1 Visual 24 9-9 111764 Frozeni 11541 1154 Visual 2-05 1 19 11765S Frozenj 15001 1 5C Visual TOPICAL REPORT ICUG-001, Revision 2 A-38 June 2003

2-05-9-2 9

1766 Frozen 1307 1307 Visual 2-05-9-3 9

1767 Frozen 1367 1367 Visual 2-05-9-4 9

1768 Frozen 1191 1191 Visual 2-05-9-5 9

1769 Frozen 1335 1335 Visual 2-05-9-6 9

1770 Frozen 976 976 Visual 2-05-9-7 9

1771 1166 1358 1166 Scale 2-05-9-8 9

1772 Frozen 1019 1019 Visual 2-05-9-9 9

1773 Frozen 1298 1298 Visual 2-06-9-1 9

1774 Frozen 1131 1131 Visual 2406-9-2 9

1775 Frozen 1500 1500 Visual 2-06-9-3 9

1776 Frozen 1260 1260 Visual 2-06-9-4 9

1777 Frozen 1507 1507 Visual 2406-9-5 9

1778 Frozen 1358 1358 Visual 246-9-6 9

1779 Frozen 1416 1416 Visual 246-9-7 9

1780 Frozen 1504 1504 Visual 246-9-8 9

1781 Frozen 1163 1163 Visual 2-06-9-9 9

1782 Frozen 1188 1188 Visual 2-07-9-1 9

1783 Frozen 1234 1234 Visual 2-07-9-2 9

1784 Frozen 1497 1497 Visual 2-07-9-3 9

1785 Frozen 1289 1289 Visual 2-07-9-4 9

1786 Frozen 923 923 Visual 2-07-9-5 9

1787 Frozen l500 1500 Visual 2-07-9-6 9

1788 Frozen 1341 1341 Visual 2-07-9-7 9

1789 Frozen 1161 1161 Visual 2-07-9-8 9

1790 Frozen 1428 1428 Visual 2-07-9-9 9

1791 Frozen 1114 1114 Visual 2-08-9-1 9

1792 Frozen 1448 1448 Visual 2-08-9-2 9

1793 Frozen 937 937 Visual 2-08-9-3 9

1794 1498 1465 1498 Scale 2-08-9-4 9

1795 Frozen 1329 1329 Visual 2-08-9-5 9

1796 Frozen 1378 1378 Visual 2-08-9-6 9

1797 Frozen 1399 1399 Visual 2-08-9-7 9

1798 Frozen _

1536 1536 Visual 2-08-9-8 9

1799 Frozen 1448 1448 Visual 2-08-9-9 9

1800 Frozen 1536 1536 Visual 2-09-9-1 9

1801 Frozen 1447 1447 Visual 2-09-9-2 9

1802 Frozen 1121 1121 Visual 2-09-9-3 9

1803 1286 1360 1287 1286 Scale 2-09-9-4 9

1804 Frozen 1362 1362 Visual 2-09-9-5 9

1805 Frozen 1504 1504 Visual 2-09-9-6 9

1806 Frozen 1259 1259 Visual 2-09-9-7 9

1807 Frozen _

1442 1442 Visual 2-09-9-8 9

1808 Frozen 1536 1536 Visual 2-09-9-9 9

1809 Frozen 1333 1333 Visual 2-10-9-1 9

1810 Frozen 1438 1438 Visual 2-10-9-2 9

1811 1079 1354 1269 1079 Scale 2-10-9-3 9

1812 935 1255 935 Scale 2-10-94 9

1813 Frozen 1045 1045 Visual 2-10-9-5 9

1814 Frozen 1283 1283 Visual 2-10-9-6 9

1815 Frozen 1435 1435 Visual 2-10-9-7 9

1816 Frozen 1363 1363 Visual 2-10-9-8 9

1817

Frozen, 1394 1394 Visual TOPICAL REPORT June 2003 ICUG-001, Revision 2 A-39

2-10-9-9 9

1818 Frozen 1358 1358 Visual 2-11-9-1 9

1819 Frozen 1435 1435 Visual 2-11-9-2 9

1820 Frozen 1452 1452 Visual 2-11-9-3 9

1821 Frozen 1426 1426 Visual 2-11-9-4 9

1822 Frozen 1404 1404 Visual 2-11-9-5 9

1823 Frozen 1429 1429 Visual 2-11-9-6 9

1824 Frozen 1435 1435 Visual 2-11-9-7 9

1825 Frozen 1477 1477 Visual 2-11-9-8 9

1826 Frozen 1411 1411 Visual 2-11-9-9 9

1827 Frozen 1394 1394 Visual 2-12-9-1 9

1828 Frozen 1345 1345 Visual 2-12-9-2 9

1829 Frozen 1483 1483 Visual 2-12-9-3 9

1830 Frozen 1411 1411 Visual 2-12-9-4 9

1831 Frozen 1458 1458 Visual 2-12-9-5 9

1832 Frozen 1370 1370 Visual 2-12-9-6 9

1833 Frozen 1233 1233 Visual 2-12-9-7 9

1834 Frozen 1447 1447 Visual 2-12-9-8 9

1835 Frozen 1339 1339 Visual 2-12-9-9 9

1836 Frozen 1536 1536 Visual 2-13-9-1 9

1837 Frozen 1305 1305 Visual 2-13-9-2 9

1838 Frozen 1388 1388 Visual 2-13-9-3 9

1839 Frozen 1320 1320 Visual 2-13-9-4 9

1840 Frozen 1248 1248 Visual 2-13-9-5 9

1841 Frozen 1406 1406 Visual 2-13-9-6 9

1842 1229 1213 1229 Scale 2-13-9-7 9

1843 Frozen 1244 1244 Visual 2-13-9-8 9

1844 Frozen 1447 1447 Visual 2-13-9-9 9

1845 Frozen 1394 1394 Visual 2-14-9-1 9

1846 Frozen 1291 1291 Visual 2-14-9-2 9

1847 Frozen 1536 1536 Visual 2-14-9-3 9

1848 1334 1402 1334 Scale 2-14-9-4 9

1849 Frozen 1500 1500 Visual 2-14-9-5 9

1850 Frozen 1500 1500 Visual 2-14-9-6 9

1851 Frozen 1443 1443 Visual 2-14-9-7 9

1852 Frozen 1424 1424 Visual 2-14-9-8 9

1853 Frozen 1497 1497 Visual 2-14-9-9 9

1854 Frozen 1447 1447 Visual 2-15-9-1 9

1855 Frozen 1411 1411 Visual 2-15-9-2 9

1856 Frozen 1467 1467 Visual 2-15-9-3 9

1857 Frozen 1463 1463 Visual 2-15-9-4 9

1858 Frozen 1291 1291 Visual 2-15-9-5 9

1859 Frozen 1239 1239 Visual 2-15-9-6 9

1860 Frozen 1398 1398 Visual 2-15-9-7 9

1861 1219 1245 1298 1219 Scale 2-15-9-8 9

1862 1330 1435 1330 Scale 2-15-9-9 9

1863 Frozen 1362 1362 Visual 2-16-9-1 9

1864 Frozen 1003 1003 Visual 2-16-9-2 9

1865 Frozen 1041 1041 Visual 2-16-9-3 9

1866 1095 1072 1095 Scale 2-16-9-4 9

1867

Frozen, 1417 1417 Visual 2-16-9-5 9

1868 Frozenl 1392 1392 Visual 2-16-9-6 9

1869 Frozen_

1497 1497 Visual TOPICAL REPORT ICUG-001, Revision 2 A-40 June 2003

2-16-9-7 9

1870 Frozen 1276 1276 Visual 2-16-9-8 9

1871 Frozen 1387 1387 Visual 2-16-9-9 9

1872 Frozen 1394 1394 Visual 2-17-9-1 9

1873 Frozen 1239 1239 Visual 2-17-9-2 9

1874 Frozen 1455 1455 Visual 2-17-9-3 9

1875 Frozen 1414 1414 Visual 2-17-9-4 9

1876 Frozen 1086 1086 Visual 2-17-9-5 9

1877 Frozen 1339 1339 Visual 2-17-9-6 9

1878 Frozen 1304 1304 Visual 2-17-9-7 9

1879 Frozen 1497 1497 Visual 2-17-9-8 9

1880 Frozen 1117 11 17 Visual 2-17-9-9 9

1881 Frozen 1035 1035 Visual 2-18-9-1 9

1882 Frozen 1058 1058 Visal 2-18-9-2 9

1883 Frozen 1161 1319 1161 ICEMANTm 2-18-9-3 9

1884 1100 1345 1100 Scale 2-18-9-4 9

1885 Frozen 1053 1053 Visual 2-18-9-5 9

1886 Frozen 1434 1434 Visual 2-18-9-6 9

1887 Frozen 1260 1260 Visual 2-18-9-7 9

1888 Frozen 1388 1388 Visual 2-18-9-8 9

1889 Frozen 1368 1368 Visual 2-18-9-9 9

1890 Frozen 1483 1483 Visual 2-19-9-1 9

1891 Frozen 1429 1429 Visual 2-19-9-2 9

1892 Frozen 1356 1356 Visual 2-19-9-3 9

1893 Frozen 1294 1294 Visual 2-19-94 9

1894 Frozen 1120 1120 Visual 2-19-9-5 9

1895 Frozen 1507 1507 Visual 2-19-9-6 9

1896 Frozen 1075 1075 Visual 2-19-9-7 9

1897 Frozen 1098 1098 Visual 2-19-9-8 9

1898 Frozen 1116 1116 Visual 2-19-9-9 9

1899 Frozen 1497 1497 Visual 2-20-9-1 9

1900 Frozen 1301 1497 1301 ICEMAN 2-20-9-2 9

1901 Frozen 1399 1399 Visual 2-20-9-3 9

1902 1175 1340 1175 Scale 2-20-94 9

1903 1080 1536 1080 Scale 2-20-9-5 9

1904 Frozen 1102 1102 Visual 2-20-9-6 9

1905 902 934 1279 902 Scale 2-20-9-7 9

1906 1040 1214 1047 1040 Scale 2-20-9-8 9

1907 Frozen 1365 1365 Visual 2-20-9-9 9

1908 Frozen 1204 1204 Visual 2-21-9-1 9

1909 Frozen 1243 1243 Visual 2-21-9-2 9

1910 Frozen 1429 1429 Visual 2-21-9-3 9

1911 791 1088 791 Scale 2-21-9-4 9

1912 Frozen 1129 1129 Visual 2-21-9-5 9

1913 Frozen 1424 1424 Visual 2-21-9-6 9

1914 Frozen 1448 1448 Visual 2-21-9-7 9

1915 1230 1361 1448 1230 Scale 2-21-9-8 9

1916 Frozer 1401 1401 Visual 2-21-9-9 9

1917 Frozer 1013 1013 Visual 2-22-9-1 9

1918 Frozer 1203 1203 Visual 2-22-9-2 9

1919 Frozer 1380 1380 Visual 2-22-9-3 9

1920 1242 1536 1242 Scale 2-22-9-4 9

1921 Frozen 1309 1309 Visual TOPICAL REPORT June 2003 ICUG-001, Revision 2 A 41

2-22-9-5 9

1922 Frozen 1451 1451 Visual 2-22-9-6 9

1923 Frozen 1314 1314 Visual 2-22-9-7 9

1924 Frozen 1195 1195 Visual 2-22-9-8 9

1925 Frozen 1340 1340 Visual 2-22-9-9 9

1926 Frozen 1307 1307 Visual 2-23-9-1 9

1927 Frozen 1256 1256 Visual 2-23-9-2 9

1928 Frozen 1361 1361 Visual 2-23-9-3 9

1929 Frozen 1299 1299 Visual 2-23-9-4 9

1930 Frozen 1390 1390 Visual 2-23-9-5 9

1931 Frozen 1358 1358 Visual 2-23-9-6 9

1932 Frozen 1297 1297 Visual 2-23-9-7 9

1933 Frozen 1183 1183 Visual 2-23-9-8 9

1934 Frozen 1159 1159 Visual 2-23-9-9 9

1935 Frozen 1318 1318 Visual 2-24-9-1 9

1936 694 727 1035 694 Scale 2-24-9-2 9

1937 1240 1307 1240 Scale 2-24-9-3 9

1938 1018 1026 1065 1018 Scale 2-24-9-4 9

1939 Frozen 1349 1349 Visual 2-24-9-5 9

1940 Frozen 1390 1390 Visual 2-24-9-6 9

1941 Frozen 1287 1287 Visual 2-24-9-7 9

1942 Frozen.

1458 1458 Visual 2-24-9-8 9

1943 Frozen_

1177 1177 Visual 2-24-9-9 9

1944 Frozen_

1363 1363 Visual Mean (lb) 1274.1 1310.3 1266.6 1278.4 Standard 146.0 145.2 157.5 154.1 Deviation (lb)

Number of 1230 1175 737 1944 Data Points rotal (lb)

_2,485,268 TOPICAL REPORT ICUG-001, Revision 2 June 2003 A-42

Table A-2. Ice Mass Sample Group (from parent population in Table A-1)

I TOPICAL REPORT ICUG-001, Revision 2 A-43 June 2003

Basket Number Row Column Bay Radial Sample Mass Method Zone Group (lb) 124 1

7 14 C

1 1350 Visual 158 1

5 18 C

2 1325 Visual 127 1

1 15 C

3 1532 Scale 26 1

8 03 C

4 1050 Visual 92 1

2 11 C

5 1322 Visual 178 1

7 20 C

6 1538 ICEMANTm 86 1

5 10 C

7 1678 ICEMANT 163 I

1 19 C

8 1101 Visual 105 1

6 12 C

9 1356 Scale 171 1

9 19 C

10 1278 Visual 195 6

22 C

1 1500 Visual 73 1

1 09 C

12 1365 Visual 29 1

2 04 C

13 1884 Scale 14 1

5 02 C

14 1145 Visual 22 1

4 03 C

15 1300 Visual 149 1

5 17 C

16 1400 Visual 265 2

4 06 C

1 1500 Visual 334 2

1 14 C

2 1468 ICEMANTm 337 2

4 14 C

3 1433 ICEMANTm 425 2

2 24 C

4 1198 Scale 386 2

8 19 C

5 1412 Visual 264 2

3 06 C

6 1643 ICEMAN" 221 2

5 01 C

7 1374 Scale 322 2

7 12 C

8 1485 Scale 364 2

4 17 C

9 1283 Visual 226 2

1 02 C

10 1100 Visual 391 2

4 20 C

1 1383 Scale 379 2

1 19 C

12 1199 Visual 310 2

4 11 C

13 1356 Visual 292 2

4 09 C

14 1245 Visual 332 2

8 13 C

15 1436 Scale 287 2

8 08 C

16 1347 Scale 478 3

1 06 C

1 1516 ICEMANT 492 3

6 07 C

2 1478 Scale 628 3

7 22 C

3 1413 Scale 487 3

1 07 C

4 1450 Scale 463 3

4 04 C

5 1426 Scale 456 3

6 03 C

6 1506 Scale 605 3

2 20 C

7 1421 Scale 450 3

9 02 C

8 1329 Scale 638 3

8 23 C

9 1458 Scale 542 3

2 13 C

10 1334 Scale 620 3

8 21 C

11 1367 Scale 501 3

6 08 12 1392 Scale 625 3

4 22 C

13 1503 Scale 464 3

5 04 C

14 1415 Scale TOPICAL REPORT ICUO-001, Revision 2 June 2003 A-44

519 3

6 10 C

15 1438 Scale 534 3

3 12 C

16 1425 Scale 811 4

1 19 B

1 1411 Scale 777 4

3 15 B

2 1218 Scale 823 4

4 20 B

3 1243 Scale 756 4

9 12 B

4 1298 Scale 842 4

5 22 B

5 1345 Scale 688 4

4 05 B

6 1264 Scale 725 4

5 09 B

7 1255 Scale 651 4

3 01 B

8 1306 Scale 702 4

9 06 B

9 1291 Scale 746 4

8 11 B

10 1397 Scale 714 4

3 08 B

11 1207 Scale 788 4

5 16 B

12 1247 Scale 805 4

4 18 B

13 1211 Scale 650 4

2 01 B

14 1320 Scale 778 4

4 15 B

15 1202 Scale 706 4

4 07 B

16 1344 Scale 883 5

1 03 B

1 1366 Scale 867 5

3 01 B

2 1248 Scale 935 5

8 08 B

3 1195 Scale 994 5

4 15 B

4 1265 Scale 936 5

9 08 B

5 1326 Scale 975 5

3 13 B

6 1329 Scale 990 5

9 14 B

7 1233 Visual 934 5

7 08 B

8 1170 Scale 917 5

8 06 B

9 1233 Scale 1022 5

5 18 B

10 1244 Scale 952 5

7 10 B

11 1305 Scale 887 5

5 03 B

12 1314 Scale 987 5

6 14 B

13 1246 Scale 898 5

7 04 B

14 1190 Scale 939 5

3 09 B

15 1185 Scale 1059 5

6 22 B

16 1207 Scale 1183 6

4 12 B

1 1258 Scale 1244 6

2 19 B

2 1230 Scale 1146 6

3 08 B

3 1159 Scale 1181 6

2 12 B

4 1225 Scale 1267 6

7 21 B

5 1110 Scale 1258 6

7 20 B

6 1192 Scale 1136 6

2 07 B

7 1183 Scale 1167 6

6 10 B

8 1363 Scale 1132 6

7 06 B

9 1338 Scale 1173 6

3 11 B

10 1212 Scale 1121 6

5 05 B

11 1218 Scale 1267 6

7 21 B

12 1110 Scale 1256 6

5 20 B

13 1149 Scale 1175 6

5 11 B

14 1288 Scale 1163 6

2 10 B

15 1198 Scale TOPICAL REPORT ICUG-001, Revision 2 A-45 June 2003

1273 6

4 22 B

16 1342 Scale 1490 7

5 22 A

1 1383 Visual 1510 7

7 24 A

2 1292 Scale 1342 7

1 06 A

3 1277 Visual 1487 7

2 22 A

4 1216 Scale 1397 7

2 12 A

5 1267 Visual 1378 7

1 10 A

6 1267 Visual 1498 7

4 23 A

7 1284 Scale 1436 7

5 16 A

8 1172 Visual 1368 7

9 08 A

9 1278 Visual 1301 7

5 01 A

10 1311 Scale 1371 7

3 09 A

11 1193 Scale 1506 7

3 24 A

12 1130 Scale 1323 7

9 03 A

13 1130 Scale 1466 7

8 19 A

14 1209 Visual 1421 7

8 14 A

15 1739 ICEMANT' 1367 7

8 08 A

16 1445 Visual 1604 8

2 11 A

1 1497 Visual 1625 8

5 13 A

2 1362 Visual 1709 8

8 22 A

3 1449 Scale 1664 8

8 17 A

4 1406 Visual 1536 8

6 03 A

5 904 Visual 1571 8

5 07 A

6 1358 Visual 1528 8

7 02 A

7 838 Scale 1660 8

4 17 A

8 1378 Visual 1520 8

8 01 A

9 770 Scale 1636 8

7 14 A

10 1330 Scale 1650 8

3 16 A

11 1202 Scale 1514 8

2 01 A

12 1429 Visual 1634 8

5 14 A

13 1181 Visual 1519 8

7 01 A

14 1090 Scale 1606 8

4 11 A

15 1376 Visual 1594 8

1 10 A

16 1240 Scale 1803 9

3 09 A

1 1286 Scale 1909 9

1 21 A

2 1243 Visual 1767 9

3 05 A

3 1367 Visual 1743 9

6 02 A

4 938 Visal 1802 9

2 09 A

5 1121 Visual 1731 9

3 01 A

6 1536 Visual 1934 9

8 23 A

7 1159 Visual 1886 9

5 18 A

8 1434 Visual 1939 9

4 24 A

9 1349 Visual 1932 9

6 23 A

10 1297 Visual 1846 9

1 14 A

11 1291 Visual 1757 9

2 04 A

12 1230 Scale 1875 9

3 17 A

13 1414 Visual 1905 9

6.

20 A

14 902 Scale 1799 9

8 08 A

15 1448 Visual 1775 9

2 06 A

16 1500 Visual TOPICAL REPORT ICUG-001, Revision 2 June 2003 A-46

Table A-3. Example Calculations (for Table A-2 sample group)

TOPICAL REPORT ICUG-001, Revision 2 A47 June 2003

o Stratified Sampling Sample Sample Mean, Standard No. of Data No. of Data No. of Data Total 95%

Total Ice Bed Mass is Size Group(s) X (lb) Deviation, s Points from Points from Points from Error of Conf.

at least (lb)

(lb)

Scale ICEMAN'h VISUAL the mean Mean (lb)

(lb) 36 1-4 1321 133 21 3

12 61.4 1259 2,447,985 72 1-8 1314 156 40 6

26 46.5 1267 2,463,030 90 1-10 1305 154 52 6

32 41.0 1264 2,456,726 108 1-12 1301 147 65 6

37 36.2 1265 2,458,818 144 1-16 1305 155 88 7

49 31.8 1273 2,475,670 Stratifi ed Sampling: Three q ntial Rows in each Radial Zone Sample Sample Radial Mean, X Standard No. of Data No. of Data No. of Total 95%

Total Ice size Group(s)

Zone (lb)

Devlation, s Points from Points from Data Error of Conf Bed Mass (lb)

Scale ICEMANTm Points the mean Mean (lb) is at least from (lb)

(lb)

VISUAL 36 Total 2,372,078 12 1-4 C

1393 143.4 5

3 4

117.0 1276 12 1-4 B

1260 70.2 12 0

0 37.1 1223 12 1-4 A

1310 144.0 4

0 8

147.3 1162 72 total 2,410,530 24 1-8 C

1415 147.2 1

11 6

1 7

76.8 1338 24 1-8 B

1258 73.8 23 0

T 1

j 33.8 1224 24 1-8 A

1268 178.0 T

6 0

18 110.0 1158 90 total l

2,409,810 30 1-10 C

1 1392 1

147.3 1

14 1

6 1

10 1 70.6 1 1321 30 1-10 B

1264 72.9 29 l

0 l

1 1 28.5 1 1235 l

30 1-10 A

1259 184.5 9

1 0

7 21 T 96.4 1 1162 LE<< i 1

2,417,634 total 36 1-12 C

1388 139.3 17 6

T 13 64.2 1324 36 1-12 B

1259 1

73.0 1

35 0

7 1

125.1 1233 7

36 1-12 A

1257 172.6 13 0

l 23 l

83.0 1174 l

II4 2,439,746 total 48 l

1-16 C

1269 185A 24 6

18 l

63.0 1206 l

48 116 B

1254 71.21 47 l0 1

120.3 1234 48 j 1-16 A

1393 148.3 17 1

J 30 167.6 j1325 TOPICAL REPORT ICUG-001, Revision 2 June 2003 A48

Original WOG Standard Technical Specification - Ice Bed FOR INFORMATION ONLY TOPICAL REPORT ICUG-001, Revision 2 A49 June 2003

3.6 CONTAINMENT SYSTEMS 3.6.15 Ice Bed (Ice Condenser)

LCO 3.6.15 The ice bed shall be OPERABLE.

APPLICABILITY:

MODES 1, 2,3, and 4.

ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. Ice bed inoperable.

A.1 Restore ice bed to 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> OPERABLE status.

B. Required Action and B.1 Be in MODE 3.

6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> associated Completion AND Time not met.

B.2 Be in MODE 5.

36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.6.15.1 Verify maximum ice bed temperature is 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />

< [27]F.

(continued)

TOPICAL REPORT ICUG-001, Revision 2 June 2003 A-50

SURVEILLANCE REQUIREMENTS (continued)

SURVEILLANCE FREQUENCY SR 3.6.15.2 Verify total weight of stored ice is

[2,721,600] lb by:

9 months

a.

Weighing a representative sample of 2 144 ice baskets and verifying each basket contains 2 [1400] lb of ice; and

b.

Calculating total weight of stored ice, at a 95%

confidence level, using all ice basket weights determined in SR 3.6.15.2.a.

SR 3.6.15.3 Verify azimuthal distribution of ice at a 95% confidence level by subdividing weights, as determined by SR 3.6.15.2.a, into the following groups:

9 months

a.

Group 1 -

bays 1 through 8;

b.

Group 2-bays 9 through 16; and

c.

Group 3-bays 17 through 24.

The average ice weight of the sample baskets in each group from radial rows 1, 2, 4, 6, 8, and 9 shall be 2 [1400] lb.

SR 3.6.15.4 Verify, by visual inspection, accumulation of ice or 9 months frost-on Structural members comprising flow channels through the ice condenser is < [0.38] inch thick.

(continued)

TOPICAL REPORT ICUG-001, Revision 2 A-51 June 2003

SURVEILLANCE REQUIREMENTS (continued)

SURVEILLANCE FREQUENCY

+

SR 3.6.15.5 Verify by chemical analyses of at least nine representative samples of stored ice:

[18] months

a.

boron concentration is 2 [1800] ppm; and

b.

pH is Ž [9.0] and

[9.5].

SR 3.6.15.6 Visually inspect, for detrimental structural wear, 40 months cracks, corrosion, or other damage, two ice baskets from each azimuthal group of bays.

See SR 3.6.15.3.

TOPICAL REPORT ICUG-001, Revision 2 June 2003 A-52

B 3.6 CONTAINMENT SYSTEMS B 3.6.15 Ice Bed (Ice Condenser)

BASES BACKGROUND The ice bed consists of over 2,721,600 lb of ice stored in baskets within the ice condenser. Its primary purpose is to provide a large heat sink in the event of a release of energy from a Design Basis Accident (DBA) in containment. The ice would absorb energy and limit containment peak pressure and temperature during the accident transient. Limiting the pressure and temperature reduces the release of fssion product radioactivity from containment to the environment in the event of a DBA.

The ice condenser is an annular compartment enclosing approximately 3000 of the perimeter of the upper containment compartment, but penetrating the operating deck so that a portion extends Into the lower containment compartment. The lower portion has a series of hinged doors exposed to the atmosphere of the lower containment compartment, which, for normal unit operation, are designed to remain dosed. At the top of the ice condenser is another set of doors exposed to the atmosphere of the upper compartment, which also remain dosed during normal unit operation. Intermediate deck doors, located below the top deck doors, form the floor of a plenum at the upper part of the ice condenser. These doors also remain closed during normal unit operation. The upper plenum area is used to facilitate surveillance and maintenance of the ice bed.

The ioe baskets held in the ice bed within the ice condenser are arranged to promote heat transfer from steam to ice. This arrangement enhances the ice condenser's primary function of condensing steam and absorbing heat energy released to the containment during a DBA.

In the event of a DBA, the ice condenser inlet doors (located below the operating deck) open due to the pressure rise in the lower compartment This allows air and steam to flow from the lower compartment into the ice condenser. The resulting pressure Increase within the ice condenser causes the ntermediate deck doors and the top deck doors to open, which allows the air to flow out of the ice condenser into the upper compartment Steam condensation within the ice condenser limits the pressure and temperature buildup in containment. A divider barrier separates the upper and lower compartments and ensures that the steam is directed into the ice condenser.

The Ice, together with the containment spray, is adequate to absorb the initial blowdown of steam and water from a DBA and the additional heat loads that would enter containment during several hours following the initial blowdown.

The additional heat loads would come from the residual heat in the reactor core, the hot piping and components, and the secondary system, including the steam generators. During the post blowdown period, the Air Retum System (ARS) retums upper compartment air through the dMder barrier to the lower TOPICAL REPORT ICUG-001, Revision 2 A-53 June 2003

compartment This serves to equalize pressures in containment and to continue circulating heated air and steam from the lower compartment through the ioe condenser where the heat is removed by the remaining ice.

As ice melts, the water passes through the ice condenser floor drains into the lower compartment Thus, a second function of the ice bed is to be a large source of borated water (via the containment sump) for long term Emergency Core Cooling System (ECCS) and Containment Spray System heat removal functions in the recirculation mode.

A third function of the ice bed and melted ice is to remove fission product iodine that may be released from the core during a DBA. Iodine removal occurs during the ice melt phase of the accident and continues as the melted ice is sprayed into the containment atmosphere by the Containment Spray System. The ice is adjusted to an alkaline pH that facilitates removal of radioactive iodine from the containment atmosphere. The alkaline pH also minimizes the occurrence of the chloride and caustic stress corrosion on mechanical systems and components exposed to ECCS and Containment Spray System fluids in the recirculation mode of operation.

It is important for the ice to be uniformly distributed around the 24 ice condenser bays and for open flow paths to exist around ice baskets. This is especially important during the initial blowdown so that the steam and water mixture entering the lower compartment do not pass through only part of the ice condenser, depleting the ice there while bypassing the ice in other bays.

Two phenomena that can degrade the ice bed during the long service period are:

a.

Loss of ice by melting or sublimation; and

b.

Obstruction of flow passages through the ice bed due to buildup of frost or ice. Both of these degrading phenomena are reduced by minimizing air leakage into and out of the ice condenser.

The Ice bed limits the temperature and pressure that could be expected following a DBA, thus limiting leakage of fission product radioactivity from containment to the environment APPUCABLE The limiting DBAs considered relative to containment SAFETY ANALYSES temperature and pressure are the loss of coolant accident (LOCA) and the steam line break (SLB). The LOCA and SLB are analyzed using computer codes designed to predict the resultant containment pressure and temperature transients. DBAs are not assumed to occur simultaneously or consecutively.

Although the ice condenser is a passive system that requires no electrical power to perform its function, the Containment Spray System and the ARS also function to assist the ice bed in limiting pressures and temperatures. Therefore, TOPICAL REPORT ICUG-001, Revision 2 A-54 June 2003

the postulated DBAs are analyzed in regards to containment Engineered Safety Feature (ESF) systems, assuming the loss of one ESF bus, which is the worst case single active failure and results in one train each of the Containment Spray System and ARS being inoperable.

The limiting DBA analyses (Ref. 1) show that the maximum peak containment pressure results from the LOCA analysis and is calculated to be less than the containment design pressure. For certain aspects of the transient accident analyses, maximizing the calculated containment pressure is not conservative.

In parUcular, the cooling effectiveness of the ECCS during the core reflood phase of a LOCA analysis increases with increasing containment backpressure. For these calculations, the containment backpressure is calculated in a manner designed to conservatively minimize, rather than maximize, the calculated transient containment pressures, in accordance with 10 CFR 50, Appendix K (Ref. 2). The maximum peak containment atmosphere temperature results from the SLB analysis and is discussed in the Bases for LCO 3.6.5, "Containment Air Temperature."

In addition to calculating the overall peak containment pressures, the DBA analyses include calculation of the transient differential pressures that occur across subcompartment walls during the initial blowdown phase of the accident transient. The intemal containment walls and structures are designed to withstand these local transient pressure dfferentials for the limiting DBAs.

The ice bed satisfies Criterion 3 of the NRC Policy Statement LCO The ice bed LCO requires the existence of the required quantity of stored ice, appropriate distribution of the ice and the ice bed, open flow paths through the ice bed, and appropriate chemical content and pH of the stored ice. The stored ice functions to absorb heat during a DBA, thereby limiting containment air temperature and pressure. The chemical content and pH of the ice provide core SDM (boron content) and remove radioactive iodine from the containment atmosphere when the melted ice is recirculated through the ECCS and the Containment Spray System, respectively.

APPLICABILITY In MODES 1, 2, 3, and 4, a DBA could cause an increase in containment pressure and temperature requiring the operation of the ice bed. Therefore, the LCO is applicable in MODES 1, 2, 3, and 4.

In MODES 5 and 6, the probability and consequences of these events are reduced due to the pressure and temperature limitations of these MODES.

Therefore, the ice bed is not required to be OPERABLE in these MODES.

TOPICAL REPORT ICUG-001, Revision 2 A-55 June 2003

ACTIONS A.1 If the ice bed is inoperable, it must be restored to OPERABLE status within 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />. The Completion Time was developed based on operating experience, which confirms that due to the very large mass of stored ice, the parameters comprising OPERABILITY do not change appreciably in this time period.

Because of this fact, the Surveillance Frequencies are long (months), except for the ice bed temperature, which is checked every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. If a degraded conditon is identified, even for temperature, with such a large mass of ice it is not possible for the degraded condition to significantly degrade further in a 48 hour5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> period. Therefore, 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> is a reasonable amount of time to correct a degraded condition before initiating a shutdown.

B.1 and B.2 If the ice bed cannot be restored to OPERABLE status within the required Completion Time, the plant must be brought to a MODE in which the LCO does not apply. To achieve this status, the plant must be brought to at least MODE 3 within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and to MODE 5 within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />. The allowed Completion Times are reasonable, based on operating experience, to reach the required plant conditions from full power conditions in an orderly manner and without challenging plant systems.

SURVEILLANCE SR 3.6.15.1 REQUIREMENTS Verifying that the maximum temperature of the ice bed is s [27]OF ensures that the ice is kept well below the meltUng point. The 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> Frequency was based on operating experience, which confirmed that, due to the large mass of stored ice, it is not possible for the ice bed temperature to degrade significantly within a 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> period and was also based on assessing the proximity of the LCO limit to the melting temperature.

Furthermore, the 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> Frequency is considered adequate in view of indications in the control room, including the alarm, to alert the operator to an abnormal ice bed temperature condition. This SR may be satisfied by use of the Ice Bed Temperature Monitoring System.

SURVEILLANCE SR 3.6.15.2 REQUIREMENTS The weighing program is designed to obtain a representative sample of the ice baskets. The representative sample shall include 6 baskets from each of the 24 ice condenser bays and shall consist of one basket from radial rows 1, 2, 4, 6.

8, and 9. If no basket from a designated row can be obtained for weighing, a basket from the same row of an adjacent bay shall be weighed.

The rows chosen include the rows nearest the inside and outside walls of the ice condenser (rows I and 2, and 8 and 9, respectively), where heat transfer into the ice condenser is most likely to influence melting or sublimation. Verifying the TOPICAL REPORT ICUG-001, Revision 2 A-56 June 2003

total weight of ice ensures that there is adequate ice to absorb the required amount of energy to mitigate the DBAs.

If a basket is found to contain < [1400] lb of ice, a representative sample of 20 additional baskets from the same bay shall be weighed. The average weight of ice in these 21 baskets (the discrepant basket and the 20 additional baskets) shall be 2 [1400] lb at a 95% confidence level.

Weighing 20 additional baskets from the same bay in the event a Surveillance reveals that a single basket contains < [1400] lb ensures that no local zone exists that is grossly deficient in ice. Such a zone could experienoe early melt out during a DBA transient, creating a path for steam to pass through the ice bed without being condensed. The Frequency of 9 months was based on ice storage tests and the allowance built into the required ice mass over and above the mass assumed in the safety analyses. Operating experience has verified that, with the 9 month Frequency, the weight requirements are maintained with no significant degradation between surveillances.

SURVEILLANCE SR 3.6.15.3 REQUIREMENTS This SR ensures that the azimuthal distribution of ice is reasonably uniform, by verifying that the average ice weight in each of three azimuthal groups of ice condenser bays is within the limit. The Frequency of 9 months was based on ice storage tests and the allowance built into the required ioe mass over and above the mass assumed in the safety analyses. Operating experience has verified that, with the 9 month Frequency, the weight requirements are maintained with no significant degradation between surveillances.

SR 3.6.15.4 This SR ensures that the flow channels through the ice condenser have not accumulated an excessive amount of ice or frost blockage. The visual inspection must be made for two or more flow channels per ice condenser bay and must include the following specific locations along the flow channel:

a.

Past the lower inlet plenum support structures and tuming vanes;

b.

Between ice baskets; C.

Past lattice frames;

d.

Through the intemiediate floor grating; and

e.

Through the top deck floor grating.

The allowable [0.38] inch thick buildup of frost or lce Is based on the analysis of containment response to a DBA with partial blockage of the ice condenser flow passages. If a flow channel in a given bay is found to have an accumulation of frost or ice > [0.38] inch thick, a representative sample of 20 additional flow channels from the same bay must be visually inspected.

TOPICAL REPORT ICUG-001, Revision 2 A-57 June 2003

f these additional flow channels are all found to be acceptable, the discrepant flow channel may be considered single, unique, and acceptable defciency.

More than one discrepant flow channel in a bay is not acceptable, however.

These requirements are based on the sensitivity of the partial blockage analysis to additional blockage. The Frequency of 9 months was based on Ice storage tests and the allowance built into the required ice mass over and above the mass assumed in the safety analyses.

SR 3.6.15.5 Verifying the chemical composition of the stored ice ensures that the stored ice has a boron concentration of at least [1 800] ppm as sodium tetraborate and a high pH, Ž [9.0] and 5 [9.5], in order to meet the requirement for borated water when the melted ice is used in the ECCS recirculation mode of operation.

Sodium tetraborate has been proven effective in maintaining the boron content for long storage periods, and t also enhances the ability of the solution to remove and retain fission product iodine. The high pH is required to enhance the effectiveness of the ice and the melted ice in removing iodine from the containment atmosphere. This pH range also minimizes the occurrence of chloride and caustic stress corrosion on mechanical systems and components exposed to ECCS and Containment Spray System fluids in the recirculation mode of operation. The Frequency of [18] months was developed considering these facts

a.

Long ice storage tests have determined that the chemical composition of the stored Ice is extremely stable.

b.

Operating experience has demonstrated that meeting the boron concentration and pH requirements has never been a problem; and

c.

Someone would have to enter the containment to take the sample, and if the unit is at power, that person would receive a radiation dose.

SR 3.6.15.6 This SR ensures that a representative sampling of ice baskets, which are relafively thin walled, perforated cylinders, have not been degraded by wear, cracks, corrosion, or other damage. Each ice basket must be raised at least 12 feet for this inspection. The Frequency of 40 months for a visual inspection of the structural soundness of the ice baskets is based on engineering judgment and considers such factors as the thickness of the basket walls relative to corrosion rates expected in their service environment and the results of the long term ice storage testing.

REFERENCES

1.

FSAR, Section [6.2].

2.

10 CFR 50, Appendix K.

TOPICAL REPORT ICUG-001, Revision 2 A-58 June 2003

Topical Report ICUG-001 List of Changes to the July 2001 Version (rev. 0) to Produce the June 2003 Version (rev. 2)

The following changes have been incorporated into the republication of topical report ICUG-001 that is dated June 2003 (revision 2). The July 2001 version (revision 0), which was the original publication, is the official previous version. Revision 1 to topical report ICUG-001 was not formally issued; all changes made in that revision are identified here and have been incorporated into Revision 2.

1. Cover page updated to specify "Revision 2" and "June 2003".

2. Page ii, Table of Contents: Added new headings in Chapters 1, 2, and 3 to reflect changes made per reference 27.

3. Page iii, List of Figures and Tables: Revised term "sample population" to "sample group" (three places) per reference 19.

4. Page iii, List of Figures and Tables: Revised titles of several tables and figures to reflect changes made per reference 27.

5. Page v, Nomenclature: Revised term "sample populations" to "sample groups" (three places). Revised definition of "Sampling without replacement" to reflect similar clarification, per reference 19.

6. Page 0-1, Active Ice Mass Management: Added following sentence at beginning of second paragraph: "Existing AMM practices manage each ice basket in the ice bed above the required mean mass supporting the safety analysis." Change per reference 22.

7. Page 0-2, Industry Challenges: Revised term "sample population" to "sample group" per reference 19.

8. Page 0-3, Industry Challenges: Revised last two paragraphs to read: "A further disparity in the historical methodology required each statistically sampled basket to contain the specified amount of ice, while the Bases allowed for individual baskets to be "light" (i.e., less than the technical specification required minimum mass) if baskets in the local area were sufficiently full. This contradiction also led to differing industry interpretations, even though the original intent was, as described by the technical specification bases, to prevent localized gross degradation of the ice bed. The technical specification methodology presented here treats this contradiction by recognizing that the two primary concerns of the ice mass design basis-and therefore the two required surveillances-are the presence of sufficient total ice mass in the bed distributed appropriately to accommodate the overall DBA response, and a sufficient minimum mass in any individual basket maintained to prevent localized areas of degradation that might challenge the DBA containment pressure response.

"The requirement for the overall DBA response is met by determining total ice mass in the bed based on a sampled group. In this manner, the word "each" is eliminated from the operability requirement, and individual baskets can sublimate during an operating cycle to whatever level their relative position in the ice bed dictates. Conversely, the minimum Page 1 of 6

List of Changes to the July 2001 Version (cont.)

individual basket mass requirement stipulates a minimum mass of ice for each of the statistically sampled baskets so that a minimum amount of ice in the basket is verified to be present. The use of each in this instance is appropriate, since the containment analysis is primarily concerned with localized degradation (i.e., a cluster of baskets with degraded mass) and the sampled group is a valid representation of the entire Radial Zone under surveillance.

As noted previously, AIMM practice will manage each basket above the required safety analysis mean, such that no individual basket would be expected to sublimate below this mean value. If a basket sublimates below the safety analysis mean value this instance is identified within the plant's corrective action program, including evaluating AIMM practices to identify the cause and to correct any deficiencies. If a basket sublimates below the minimum individual basket mass requirement, then this condition is TS prohibited, necessitating reporting per the requirements of 10CFR50.73 in addition to corrective action program determination of cause and appropriate corrective actions. Certain individual baskets in the corners of the ice bed would typically pose the greatest challenge to maintaining their stored ice mass above the safety analysis mean, due to the relatively high sublimation rates in these areas. However, AIMM practice would generally identify these baskets for servicing every outage, thereby enabling the ice mass in these baskets to be maintained above the safety analysis mean, which would prevent any challenge to the surveillance requirements."

Changes per references 22 and 27. Also revised term "sample population" to "sample group" (two places) per reference 19.

9. Page 0-3, Summary of Significant Aspects: Clarified that industry commitments to manage the ice mass in each basket above the required technical specification mean, a statistically random sample in each Radial Zone, and a defined minimum individual ice mass per basket combine to become the basis for verification of appropriate ice distribution in lieu of a limited azimuthal row-group surveillance, and deleted reference to minimum blowdown ice mass per reference 22.

10. Page 04, Figure 0-1: Revised term in flow diagram "Blowdown Limit" to "Minimum Individual Basket Limit" per reference 22.

11. Page 0-5, Table 0-1: Revised fourth bullet to: "A surveillance for minimum total ice mass in the bed assures the initial conditions of the DBA analyses". Deleted fifth bullet. Revised sixth bullet to: "A surveillance for minimum ice mass in each individual basket prevents localized degradation to avoid any challenge to the DBA containment pressure response". Revised eighth bullet to: "Proper azimuthal distribution of ice in the ice bed is no longer assessed by a separate surveillance requirement; it is implemented through established industry-wide maintenance practices that manage each ice basket above the required safety analysis mean and confirmed through as-found random sampling techniques". Revised ninth bullet to: "All ice baskets in the parent population are subject to random statistical sampling, as opposed to only two-thirds of the population subject to representative sampling." Changes per references 22 and 27.

12. Pages I-1, I-2, Design Basis: Revised second paragraph to clarify the description of the original short-term containment pressurization analysis (TMD). Revised third paragraph to clarify the description of the long-term containment pressurization analyses (LOTIC/GOTHIC), and the link to localized degraded regions of ice mass in the bed.

Changes per reference 27.

Page 2 of 6

List of Changes to the July 2001 Version (cont.l

13. Page 1-2, Design Basis: Revised parenthetical item 2 at end of paragraph to: "enough ice mass is sufficiently distributed such that localized regions of mass degradation do not exist in the ice bed", per reference 27.

14. Page 1-2, Design Basis: Revised fourth paragraph to clarify the use of mass detennination uncertainty. Changes per reference 27.

15. Page 1-2, Original Ice Mass Technical Specification Requirements: revised "sample population" to "sample group" (two places), per reference 19.

16. Page 1-3, Original Ice Mass Technical Specification Requirements: Revised paragraph under Figure 1-1 to read: "In addition, these masses were used as the verification that a degraded localized region did not exist in the ice bed that would challenge the DBA pressure response. If a basket in the 144-basket statistical sample was found to weigh less than the required individual limit (described as "light"), the sample was to be increased in the localized region (i.e., the affected Bay) by 20 baskets. The averaged mass of the 20 additional baskets and the "light" basket was then required to meet the surveillance limit". Deleted reference to the long-term phase of the DBA in the last sentence on the page. Changes per references 22 and 27.

17. Page I-4, Historical Data: Clarifications for consistency with other sections. Changes per reference 27.

18. Page 1-4, Historical Data Analysis: Revised term "sample population" to "sample group",

per reference 19. Minor editorial revisions.

19. Page I-5, Historical Data Analysis: Revised last paragraph to clarify AIMM basis, per reference 27.

20. Page I-5, AIMM Methodology: Added new section, per reference 27.

21. Page I-6, Determination of Basket Mass in AIMM Practice: Added new section, per reference 27.

22. Page I-6, The Radial Zone Concept: Revised title of section for clarification, per reference 27.

23. Page 1-7, The Radial Zone Concept: Clarification revisions for AIMM description, per reference 27.

24. Page 1-8, Regions of Localized Degraded Mass: Added new section, per reference 27.

25. Page 1-9,

Conclusions:

Editorial revisions made to clarify design basis requirements basis description. Changes per reference 27.

26. Page 1-10,

Conclusions:

Revised first paragraph on page to read, "The minimum individual basket mass surveillance requirement is based on the minimum amount of ice needed in each basket to avoid localized regions of degradation in the ice bed that might challenge the DBA pressure response. This limit is derived from sensitivity runs performed using the three-dimensional GOTHIC analytical code. Concurrent assurance that localized regions of gross degradation do not exist in the ice bed is given via Active Ice Mass Management (AIMM)

Page 3 of 6

List of Changes to the July 2001 Version (cont.)

methodology, which is based on current industry maintenance practice and asserts that the ice mass in each basket in the ice bed will be managed above the required safety analysis mean, and serviced prior to reaching this limit. Therefore, the methodology for the requirement of minimum individual basket mass has two elements: 1) active maintenance practice (AIMM) that manages each basket to the required safety analysis mean, and 2) a defined surveillance minimum limit of 600 lb per basket." Changes made per reference 27.

27. Page II-1, Purpose/Scope: Revisions made to description of Section purpose to clarify additional detail regarding alternate mass determination and uncertainty standards. Changes per reference 27.

28. Page 1-1, Preferred Ice Mass Determination Method: Revisions made to clarify calibration of load cells. Minor editorial changes. Changes per reference 27.

29. Pages I1-1, II-2&II-3, Alternate Ice Mass Determination Methods: Revisions made to add detail regarding the use of alternate mass determination methods. Added description of software projection methodology and visual estimation methodology. Added description of need for industry standard for uncertainty and documentation. Changes per reference 27.

30. Pages 1-3, Standards: Ice Basket Mass Determination Uncertainty: Added new section per reference 27.

31. Page II-13,

Conclusions:

Revised entire section to reflect the additional detail added to the chapter regarding the development of alternate ice basket mass determination uncertainty and summarize the hierarchy of mass determination techniques, per reference 27.

32. Page mI-1, Purpose/Scope: Editorial changes for consistency, per reference 27.

33. Page E-2, Ice Mass Statistical Strategy: Revised the term "sample population" to "sample group" (four places). Corrected mislabeled variable in equation for s and in definition of Xi.

Change per reference 19. Added clarification to description of Equation 3.1, per reference 27.

34. Page E-3, Ice Mass Statistical Strategy: Revised term "sample population" to "sample group", per reference 19. Added clarification to description of Equation 3.2, per reference 27.

35. Page E-3, Sample Size: Deleted the parenthetical statement "(the probability density function of which is a symmetric bell-shaped curve)", per reference 19.

36. Page E14, Sample Size: Revised term "sample population" to "sample group" (five places),

per reference 19. Editorial changes per reference 27.

37. Page Im-5, Sample Size: Revised termn "sample population" to "sample group" (two places),

per reference 19.

38. Page IH-7, Alternate Mass Determination Methods: Revised wording for clarity and consistency. Changes per reference 27.

39. Page I-7, Table 3-1: Revised Note 2 under the table to: "The error values shown may not be equal to the one-sigma random error defined in Equation 3.2. Plant-specific procedures will determine the appropriate value to use in Equation 3.2 and will normally represent two standard deviations for any alternate mass determination method". Changes per reference 19.

Page 4 of 6

List of Changes to the July 2001 Version (cont.)

40. Page m1I-9, Alternate Basket Selection Strategy: Revised term "sample population" to "sample group", per reference 19.

41. Page 1-10, Applications of Sampling Plan: Revised term "sample population" to "sample group" (four places), per reference 19.

42. Page 11-l l, Table 3-3: Revised termi "sample population" to "sample group", per reference 19, and added an introduction to Table 3-4 for clarity.

43. Pages IE-12 through En-15, Table 34: Revised term "sample population" to "sample group" (four places, in title), per reference 19.

44. Pages EII-15 through 11-17, Detailed Analysis: Radial Zone A: added new section per reference 27.

45. Page E-18, Table 3-6: changed table number to accommodate new section, per reference 27.

46. Page R-2,

References:

Added the following sequentially numbered references:

19. ICUG Response to NRC Request for Additional Information, R.S Lytton letter to NRC dated June 12, 2002 (w/enclosure).

20. ICUG Response to NRC Request for Additional Information, R.S Lytton letter to NRC dated October 10, 2002 (w/enclosure).

21. ICUG Response to NRC Request for Additional Information, R.S Lytton letter to NRC dated October 22, 2002 (w/enclosures).

22. ICUG Response to NRC Request for Additional Information, R.S. Lytton letter to NRC dated November 26, 2002 (w/enclosures).

23. Everhart, Jerry, Determining Mass Measurement Uncertainty, January 1997.

24. Abernathy, R.B., et al, and Thompson, Jr., J.W., Measurement Uncertainty Handbook, January 1980.

25. McClave, James T., and Dietrich, Frank H., A First Course in Statistics, third edition, copyright 1989.

26. Eisenhart, C., Expression of Uncertainties of Final Results, Precision Measurement and Calibration, NBS Handbook 91, Vol. I, February 1969.

27. USNRC Draft Safety Evaluation for Ice Condenser Utility Group Topical Report No.

ICUG-00 1, Revision 0: Application of the Active Ice Mass Management Concept to the Ice Condenser Ice Mass Technical Specification, dated May 6, 2003 (w/enclosure).

47. Page A-1, Appendix A: revised "sample population" to "sample group", per reference 19.

48. Page A43, Appendix A: revised "sample population" to "sample group", per reference 19.

49. Page A-47, Appendix A: revised "sample population" to "sample group", per reference 19.

50. Added this list of changes to the back.

Page of 6

List of Changes to the July 2001 Version (cont.!

51. Added a list of attached ICUG-NRC correspondence to the back.

52. Attached ICUG-NRC correspondence (references 19-22, and 27) to the back.

Page 6 of 6

Topical Report ICUG-001 List of Attached Correspondence

1. September 18, 2001 original submittal letter, R.S. Lytton to NRC

2. June 12,2002 response to NRC questions, R.S. Lytton to NRC

3. October 10, 2002 response to NRC questions, KS. Lytton to NRC

4. October 22, 2002 response to NRC questions, R.S. Lytton to NRC

5. November 26, 2002 response to NRC questions, R.S. Lytton to NRC

6. May 6, 2003 Draft Safety Evaluation Report, NRC to R.S. Lytton

7. May 29, 2003 Draft Revision 2 to ICUG-001 submittal letter, R.S. Lytton to NRC

Duke Duke Power LEPower.

526 South Church Street 14wwpower.

PO~~~~~~~~~~~~~~~~.o x 1006 Ch2rkore, NC 28201-1006 September 18, 2001 U. S. Nuclear Regulatory Commission Washington, D. C. 20555-001 Attention: R. Heman (addressee only)

Subject:

Ice Condenser Utility Group Topical Report No. ICUG-01:

Application of the Active Ice Mass Management Concept to the Ice Condenser Ice Mass Technical Specification Gentlemen:

Please find enclosed non-proprietary topical report ICUG-001, "Application of the Active Ice Mass Management Concept to the Ice Condenser Ice Mass Technical Specification."

This report is submitted by the Ice Condenser Utility Group (ICUG) for NRC review and approval. This report describes the basis and methodology to support an industry-proposed revision to the generic Ice Bed Technical Specification, specifically, the ice basket weighing surveillance. The proposed revision to the generic technical specification will be submitted to the MERITS Working Group / NEI Technical Specification Task Force in the fall of 2001.

If you have any questions or need additional information, please contact the undersigned at (704) 382-3970.

Sincerely, R. S. Lytton Chair, Ice Condenser Utility Group Enclosure xc(w/enclosure): Ron Hernan (addressee only, 10 copies)

Document Control Desk (one copy)

Duke Duke Power

[ Power Energy Ccntcr lowwPower.

PO~~~~~~~~~~~~~~~~~~~.ox 1006 A D.e E.V Cya.wpry Charoc. NC 28201-1006 June 12,2002 U. S. Nuclear Regulatory Commission Washington, D. C. 20555-0001 Attention: R Heman (addressee only)

Subject:

Responses to Questions on Ice Condenser Utility Group Topical Report No.

ICUG-001, Rev. 0: Application of the Active Ice Mass Management Concept to the Ice Condenser Ice Mass Technical Specifi cation, and TSTF-429, Rev. 0 (TAC Nos. MB3379 and MB3938)

Gentlemen:

On September 18, 2001, the Ice Condenser Utility Group (ICUG) submitted the subject Topical Report ICUG-001, Rev. 0 to the NRC for review and approval. Subsequently, the NEI Technical Specification Task Force submitted related TSTF-429 to the NRC for approval as well. By letter dated May 16, 2002, the NRC staff provided questions regarding the subject Topical Report and TSTF-429. On May 21, 2002, the NRC Lead Project Manager and Reviewers attended a telecon with members of ICUG in order to clarify the staffs questions regarding the Topical Report and the TSTF-429 submittal.

Enclosed are formal responses to each of the staffs questions.

The enclosed information should resolve all outstanding issues related to the review of Topical Report ICUG-001, Rev. 0 and TSTF-429, Rev. 0.

The Topical Report will be revised and re-issued upon receipt of the Safety Evaluation Report to incorporate those revisions described in the enclosure, as appropriate.

If you have any questions or need additional information, please contact the undersigned at (704) 382-3970 or rslvtton(&duke-ener.com.

Sincerely, R. S. Lytton Chair, Ice Condenser Utility Group Enclosure xc(w/enclosure): Ron Heman (addressee only, 10 copies)

Document Control Desk (one copy)

Enclosure Responses to Request for Additional Information Topical Report ICUG-OO1, Rev. 0 and TSTF429 General Commet The proposed surveillance requirements for ice bed ice mass described by topical report ICUG-001, Rev. 0 and TSTF-429 are generated to be in alignment with the established and documented design basis for the ice condenser system, which entails protection of containment and containment structures via mitigation of post-accident high energy steam-related pressure increases in both the short-term (blowdown) phase and the long-term (post-blowdown) phase of a Design Basis Accident (DBA). The purpose of the proposed surveillance requirements is to ensure that the amount of ice available will provide sufficient pressure suppression to maintain the peak containment pressure following a DBA below the containment design pressure. The key safety parameters for the bounding safety analyses at each ice condenser plant related to the surveillance requirements proposed by topical report ICUG-001, Rev. 0 and TSTF-429 are represented by:

1. A minimum total amount of ice in the ice bed, and

2.

Adequate distribution of this ice.

These parameters are also the basis for the current version of the surveillance requirements, and as such have been reviewed by the staff previously.

Much of the following information related to Topical Report ICUG-OI, Rev. 0 involves Licensee actions in both the technical specification arena (i.e., IOCFR50.36), and the maintenance arena (i.e., IOCFR50, Appendix B). The topical report refers to existing industry-wide practices related to the maintenance of ice condenser ice mass as the Active Ice Mass Management program (AIMM), which is a new term for the existing maintenance program. These plant-specific maintenance practices have historically proven to be successfil in establishing and maintaining adequate ice mass and distribution in the ice beds. Formal plant-specific documentation of them will be a part of the implementation plan for the proposed surveillance requirements.

Page 0-1, 2nd paragraph of the topical report indicated that the process of replenishing the ice baskets to restore ice bed mass based on the monitoring of varying sublimation rates during the cycle is the basis of the Active Ice Mass Management (AIMW concept The topical report also indicated that it will revise and maintain the Technical Specifications (TS) to acconmodate AMM methodology.

A.

How does the AIMM methodology relate to the improved TS?

Resvonse As described in the topical report, plant-specific maintenance practices relating to the ice bed mass are comprised of: 1) Licensee awareness of predicted ice bed mass characteristics at any point in time via knowledge of ice bed sublimation rates confirmed over many operating cycles, and 2) de facto ice bed replenishment philosophy, which replaces needed ice mass each outage by selecting baskets based on each basket's sublimation rate trend. In essence, the maintenance practices ensure adequate ice mass exists for the entire operating cycle length (and often much longer), while the surveillance requirements delineate the limited conditions for operability. This is a much improved technical specification/operability approach (and consistent with the IOCFR50.36 definition) since it emphasizes the responsibility for maintaining operability of the ice bed rests with the Licensees' maintenance process through IOCFR50, Appendix B, while the proposed surveillance requirements assure the necessary quality of the ice bed is being adequately maintained. As such, Page 1 of 14

plant-specific ice bed maintenance practices are, and must remain, active, ie., monitoring of sublimation rates and ice basket masses is an ongoing process from cycle to cycle.

As a result of the linkage between plant-specific maintenance practices and the TS, the proposed surveillance requirements are also simplified, as descnbed in the topical report (see Table 0-1).

Notably, the proposed ice mass surveilances are to be performed in an as-found (pre-maintenance) condition, which assures the design basis limits (limited conditions for opersbility) for the ice bed are met in a depleted condition for each surveillance intervaL This assessment would generally take place during, or just prior to, a refueling outage. The proposed surveillance requirements are, by themselves, adequate to detect any unexpected degradation of ice mass that would challenge the design basis limits. In companison, the curr-ent ice mass surveillances are performed in the as-left condition, which assures the design basis limits plus specified sublimation allowances are met The current surveillance requirements also rely on plant-specific maintenance practices to identify any as-found conditions that might challenge the design basis limits.

Performing the proposed surveilance in the as-found condition enhances the ability to demonstrate the ice bed is capable of performing its specified function in a depleted state, which is a simpler alignment with verifying that the initial conditions of the safety analysis are always maintained.

B.

Please descnbe the typical AIMM methodology in ice management, for example, how the AIMM wil monitor sublimation rates. Is monitoring continuous or periodic? If it is periodic, how often will it be? What criteria would be used in determining inadequate ice mass within some ice basket? During the operating cycle, what are the ice replenishment procedures inmmediately following an indication of inadequate ice mass within some ice baskets? Provide copies of these procedures.

Response

Domestic ice condenser plants have been amassing ice basket nass and sublimation data for many years, partly as a result of original and current technical specification requirements, but also as a result of augmented ice mass detenmination to facilitate maintenance program effectiveness. In this sense, the monitoring of ice mass depletion rates is periodic, occurring each time the plants perform periodic mtenance-lated ice basket nss determination (weighing) procedures.

Sinee ice mass depletion rates tend to be linear and consistent over time, with sufficient historical data the mass of ice in any basket can be predicted, as descnbed in Chapter II of the topical report If an anomaly occurs that could cause ice mass depletion rates to differ from those expected (e.g.,

ninor steam leaks in containnent that are sufficient to open the Inlet Doors), discovery would come from either Control Room indicators, current ice bed tenperature surveillance requirements or frequent procedurally-mandated online ice condenser inspections performed by plant staff, and resolution would come from a plantes Corrective Action Program. In general, current technology and technical specification controls (e.g., flow area blockage surveillance) do not allow replenishment of ice mass in baskets on-line, as this is currently performed industry-wide only during Unit shutdowns. Should a condition develop which caused a loss of reasonable assurance of neeting the proposed surveilance requirements, the remedial actions of current Technical Specifications will be adequate to direct placing the Unit in a safe mode of operation as necessary.

Current plant-specific maintenance philosophy assures ice bed quality via a per-basket projection of future ice nass. Using the histoncal sublimation rates descnbed earlier, a projection of future ice basket mass is made after an assessment of the basket's current (pre-maintenance) mass is performed. The lower limit of this projection is compared to the surveillance requirement If the basket is determined to have sufficient ice in it to last another cycle without challenging this limit, then the basket is left as-is. If there is not sufficient ice in the basket, it is scheduled for service and replenished. After all appropriate ice baskets are replenished, the as-eft surveillance requirements (which currently include a uniforn sublimation allowance for all baskets regardless of ice bed position) are verified to be met with 95% confidence. Ii under the current surveillance, a 'light" Page 2 of 14

basket is discovered, then the individual masses of twenty additional ice baskets from the'vicinity of the light basket are added to the mass of the light basket and averaged; this result is then inserted into the statistical analysis as the 95% confidence mean for that sample. This entire maintenance/surveillance process, successfully used industry-wide for many collective operating cycles, assures that the overall ice bed mass is actively managed to the surveillance requirement limits. This inherently protects the ovcrall DBA analysis parameters, and is the foundation of the proposed ice mass surveillance requirments descrbed by topical report ICUG-00land TSTF-429.

Under the proposed ice mass surveillance requirements, formal documentation of existing ice mass maintenance practices would be part of plant-specific TS implementation, since these practices would now become directly associated with satisfying the as-found (pre-maintenance) surveillance requirements and assuring compliance with the limited conditions for operability.

Since the proposed surveillance requirement limits no longer contain sublination or error allowances and limit individual ice basket mass to the blowdown minimum discussed below, these allowances and the methodology by which they are determined would also be formally documented at each plant An acceptable method that is expected to be utilized would entail each plant locating an established plant specific criteria for selecting baskets for ice mass replenishment in procedures that are maintained per OCFR50, Appendix B and OCFR50.59. A copy of such procedures is not currently available, since these criteria will be established prior to the first use of such procedures following implementation of the proposed surveillance requirements.

As discussed in the topical report, current plant-specific maintenance philosophy will remain consistent with the implementation of the proposed ice mass surveillance requirements; in the framework of the proposed version, the mean ice mass in each Radial Zone (as opposed to each ice basket) will be actively managed to meet or exceed the overall design basis limit defined by the DBA analysis parameters at the end of each cycle. The process of managing the ice mass will be directed by plant-specific instructions or procedures per IOCFR50, Appendix B, with any changes to this process controlled per the rules of IOCFR50.59.

As described by the proposed ice mass surveillance requirements, an individual ice basket in the bed is only deficient if it contains less than the minimum required amount of ice to prevent a localized area of degradation that would challenge the DBA containment pressure response (generally around [600] lb of ice). This limit is an absolute per sample basket limit; sampled basket masses are not averaged to show compliance with it as is done in the Radial Zone limit case. The overall DBA analysis pamneters (ie., short-term + long-term response) will be protected by those plant-specific maintenance procedures that manage the per basket ice mass in a given Radial Zone to the ice mass required by the overall DBA analysis limits (in the proposed generic version, this is a uniform [733,400] lb of ice per Radial Zone, corresponding to a mean mass of about [1132] lb per basket), and verified by the random sampling plan outlined in Chapter III of the topical report As discussed therein, overall operability of the ice bed is assured with 95% confidence by computing the total mass of ice in each of the three defined Radial Zones, as determined by a random statistical sampling of individual baskets and determining the 95%

confidence mean (pi,).

Since ice mass depletion rates in these Zones are well known, replenishment of sublimated ice during an outage (active mass management) assures that the ice bed will be capable of performing its safety function at any time during the cycle.

• Changes per ICUG-OOI. Revision I (References 21 and 22)

Page 3 of 14

C At the beginning of an operating cycle, what is the aount of ice to be added to the ice condenser by AIMM methodology to account for the sublimation? How does ADM methodology determine this amount?

ResPOnse Specific processes for determung ice mas replenishment scope dunng a refueling outage vary from plant to plant, but generally they utilize as-found augmented ice mass determination as descibed previously in the response to question #1B.

By using historical sublimation rates for these baskets, the mass of ice in the baskets at any time in the future can be predicted (see Chapter II of the topical report). If this prediction shows an ice basket mass will not continue to support the limited conditions delineated by the surveillance requirements until the next scheduled outage, the basket is serviced prior to the operating cycle.

Once the basket is serviced, its increased nass is determined to verify the condition. This is a fundamental aspect of existing plant-specific maintenance philosophy, and reflects long-standing industry-wide practice. Upon implementation of the proposod as-found surveillance requirements, maintenance of the ice bed to ensure the appropriate amount of ice mass is restored prior to each operating cycle will be included in plant-specific instructions or procedures per IOCFR50, App. B, with any changes controlled per the rules of IOCFR50.59.

2.

Describe how your proposed inplementation of AIMM methodology wili ensure that the ice inventory will renain adequate to nitigate accidents throughout the operating cycle.

Resnonse The as-found surveillance proposed by the revised surveillance requirements verifies that a plant's maintenance philosophy sustains sufficient ice mass in the baskets to assure the design basis limits are not challenged during an operational cycle. By showing that the ice mass in the bed at the end of a cycle is still adequate to maintain operability, the as-found (pre-naintenance) surveillance provides a level of assurance that an as-left (post maintenance) surveillance could not. As discussed previously, plant-specific maintenance practices will maintain the required quality of the ice bed and protect the DBA analysis parameters, and the proposed ice mass surveillance requirements will assure the necessary quality of the ice bed for the entire cycle. This approach is also more consistent with the OCFR50.36 defunition of a lirniting condition of operation as "the lowest functional capabilities or perfornance levels of equipment." The as-found ice nmss surveillance is currently a portion of the D.C. Cpok Nuclear Plant TS (Reference TAC Nos.

MA6766 and MA6767).

The first performance of the proposed as-found surveillance requiments will be at the end of the same operating cycle for which the current as-left surveillance was performed. Therefore, an opportunity is provided to verify the adequacy of the maintenance of the ice bed prior to the beginning of the first operating cycle after implementation of the new surveillance requirements.

Maintenance activities which affect the quality of the ice bed are directed by instructions or procedures consistent with IOCFR50, Appendix B, Criterion V. Changes to this maintenance that could potentially affect the quality of the ice bed are controlled by the rules of IOCFR50.59.

Therefore, the first performances of the proposed surveillance requirements will confirm that existing maintenance is adequate to maintain the required ice inventory necessary to mitigate accidents throughout the operating cycle. Any changes to this maintenance will not adversely affect the necessary quality as controUed by the rules of 10CFR50.59, and assured by subsequent performances of the proposed surveillances.

3.

Page 0-2, last paragraph of the report indicated that the altemate sample basket is selected from the vicinity of the initial sample. The alternate selection criteria have been designed around the Radial Zone concept, in which baskets in the same Radial Zone generally have sinilar mass.

Alternate selections are representative of initial selections as long as they have the same Page 4 of 14

probability of being selected as an initial selection and can be expected to have similar characteristics as an initial selection.

The staff finds that the alternate selection criteria were based on the assumptions of having similar mass and same probability of being selected. However, the baskets in the inner Zone C may not satisfy the above assumptions. First, it appears that the baskets in Radial Zone C (rows 7, 8, and 9) may not have similar mass. This is based on the staff's observation of Table 1-1 and Figure 1-2 of the report that significant differences in sublimation rates appear among rows 9, 8, and 7.

Secondly, as shown in Table A-I of the report, significandy more frozen ice baskets exist in row 9 than in rows 8 or 7. Therefore, a higher probability exists for selecting an alternate non-frozen basket from row 7 or 8 than for selecting a frozen basket in row 9. This is not consistent with the assumption that the alternate selection methodology "have the same probability of being selected as an initial selection and can be expected to have similar characteristics as an initial selection."

Please provide an explanation of why these two deviations from the above assumptions of alternate selection criteria will or will not affect the accuracy of the weight measurement.

Response

The Radial Zone groupings described by the topical report and TSTF-429 are:

I Radial Zone A: Rows 7, 8, and 9 (innermost Rows next to the Crane Wall)

Radial Zone B: Rows 4, 5, and 6 (middle Rows of the ice bed)

I Radial Zone C: Rows 1, 2, and 3 (outermost Rows next to Containment).

The topical repores reference to the probability of an ice basket being initially selected for the 95% confidence sample analysis is based on a blind, random sampling strategy that includes all rows of the ice bed, including Rows 3,, and 7 (the current surveillance requirement excludes these rows). Therefore, when the End-of-Cycle (as-found) surveillance is performed under the proposed version, each basket in the Radial Zone under surveillance has the same probability of being initially selected as any other ice basket in the Zone. This sampling technique will generally result in a normal distribution (as noted in the topical report), with the required 95% confidence in the total mass of the Zone assured by the 'Students t-test" approach. It is also true that for a given Row 9 initial sample sclection, the probability of this basket being frozen is higher than in any other row. However, as Figure 0-1 in the topical report schematically shows, prior to alternate basket selection alternative means for deternining the mass of the originally selected frozen basket will be utilized if available (e.g., manual lifting, ICEMAN' projection, Visual Inspection).

Alternate selection of another ice basket as a statistical replacement would typically indicate that the original selection is obstnted and its mass cannot be determined for the purposes of the surveillance. Therefore, the alternate selection criteria were developed based on the similar sublimation behavior of baskets in the same Radial Zone and dte need to preserve the random sampling of local areas in the ice bed for discovery of any gross deficiencies.

The Radial Zone grouping philosophy considers that baskets in the same Radial Zone will sublimate through their operating lives' to approximately the same mean mass. Because of the noted sublimation differences between rows, baskets in Radial Zone A (and the other Zones) are actively managed to the design basis limit such that every basket in the Zone inherendy contains a generally similar mass at the end of the operating cycle. This is due to different replenishment frequencies, a process which has the effect of converging the mean basket mass in a given Zone.

Since Row 9 baskets are characteristically the most likey to be frozen and have higher sublination than baskets in other rows, the beginning-of-cycle mass of stored ice in this row is typically higher than in Row 7 or Row 8. Therefore, it is likely that an alternate selection of another sample basket from Row 7 or Row 8 would contain the same, or conservatively less, stored ice than that of a Row 9 basket in the as-found condition.

In practice, localized groups of baskets along the same Row will also sublimate at different rates, depending on their proxinity to specific heat sources (such as the End Walls). This effect, however, generally extends to the other baskets in the vicinity (see Figure 1-2 in the topical Page5 of 14

report), further supporting the proposed alternate selection strategy, which not only linits the alternate selection to the same Radial Zone as the original selection, but also to the same Bay.

In addition to the above, frequency restrictions were established in the alternate selection criteria so that the statistical validity of the 95% confidence sample would be further protected. The criterion established in the topical report prohibits the repeat use of an ice basket which was analyzed as an alternate in any of the tree most recent surveillances that included the Bay-Zone involved. This restriction, coupled with the potential of multiple statistical sample selections from a single Bay-Zone (which would further reduce the availability of available alternates), ultimately requires that plants have access to as many baskets as possible for the determination of mass.

The conbination of this alternate selection criteria and active management of the ice bed assures a 95% confidence level in the total mass of ice in any Radial Zone and protects the ice bed from localized gross deficiencies.

4.

Page 0-3, 3rd paragraph of the report indicated that the blowdown phase requirement stipulates a minimum mass of ice for each of the baskets so that a minimum, amount of ice is verified to be present. Further, the blowdown mass is based on the data from the original Westinghouse Waltz-Mill testing.

A.

Explain how plant-specific minimum mass of ice for each of the baskets is derived from the blowdown data of the original Westinghouse Waltz-Mill testing. Provide the referred testing data and a description of the testing.

Response

The original surveillance requirements for ice mass included a provision for a "light" basket as follows:

"If a basket is found to contain < [1400] lb of ice, a representative sample of 20 additional baskets from the same bay shall be weighed. The average weight of ice in these 21 baskets (the discrepant basket and the 20 additional baskets) shall be > [1400] lb at a 95% confidence level."

The above Technical Specification provision does not define a minimum ice mass for an individual basket However, this provision does assure no local area is grossly deficient by assuring the mean mass of 21 baskets in the affected bay offsets the discrepancy of the light basket.

The proposed surveillance requirements provide a minimum ice mass limit for an individual basket defined by each plant's safety analysis (WCAP-15699, Rev. 1, 'TVA Watts Bar Nuclear Plant Unit 1 Containment Integity Analyses for Ice Weight Optimization Report," August 2001, describes a similar approach previously reviewed by the staff). By establishing this minimum requirement on an individual basket basis, the mass distribution requirements of the safety analysis are more specifically addressed.

The UFSAR for each of the domestic ice condenser plants contains a summary of ice bed DBA response as predicted by both the TMD analysis and full scale testing performed by Westinghouse at the Waltz-Mil Facility in 1968, and again in 1973. The ice melt predictions for the ice beds during the blowdown and long-term phases of the DBA are shown graphically, and indicate the total mas of ice that is consumed during each phase. For example, for McGuire Nuclear Station, the ice bed DBA response for the peak containment pressure transient is represented by the attached Figure 1 (corresponding figures from the other domestic ice condenser plants are referenced in the response to question #4B).

Page 6 of 14

From Figure 1, the end of the blowdown phase (ie, fiom t=O sec to approximately t-30 sec) shows a total ice melt of about [560,000] lb, which is equivalent to about [288] lb of ice per basket. This represents the minimum amount of ice per basket that will withstand the blowdown phase of the DBA, essentially preventing the "burn-through" scenario described in the topical report. Similarly, for the other ice condenser plants:

Catawba Nuclear Station minimum blowdown ice mass = [288] lb/basket Sequoyah Nuclear Plant minimum blowdown ice mass = (325] b/basket Watts Bar Nuclear Plant minimum blowdown ice mass = [313] lb/basket D.C. Cook Nuclear Plant mininum blowdown ice mass = 334] lb/basket The Westinghouse full scale Waltz-Mill Facility tests referred to in the topical report are documented in a series of proprietary WCAPs as follows:

3-WCAP-8110, Supplement 6: "Test Plans and Results for the Ice Condenser System -

Ice Condenser Full-Scale Section Test at the WaltzMill Facility", May 1974.

This supplement to WCAP-81 10 describes the facility test apparatus, procedures, data acquisition, instrumentation, test scale factors, and blowdown system capabilities for the initial series of tests run in 1968. In addition, it discusses the Transient Mass Distribution (TMD) model predictions for the tests, the blowdown analysis, and test results.

b-WCAP-8110, Supplement 7: "Test Plans and Results for the Ice Condenser System -

Answers to AEC Questions on Report WCAP-8282", May 1974.

This supplement to WCAP-8110 addresses responses to AEC issues on the Waltz-Mill testing described by WCAP-8282. Covered are the TMD ice melt predictions for the Waltz-Mill tests, issues related to hardware, moisture entrainment, water film on ice condenser surfaces, and bed exit temperatures.

1-WCAP-8282: Final Report Ice Condenser Full-Scale Section Tests at the Waltz-Mill Fadlity", February 1974.

This report describes the two blowdown test series performed by Westinghouse at the Waltz-Mill Facility (1968 and 1973), including test descriptions, results, and analysis.

3 WCAP-8282, Addendum 1: "Answers to AEC Questions on Report WCAP-8282",

May 1974.

This addendum also addresses responses to AEC questions on the Waltz-Mill testing.

Covered are the TMD ice melt predictions, hardware issues, LOTIC parameter studies, mass and energy balances for the facility, and resulting ice melt calculations.

Page 7of14

Figure 1 Peak Containment Pressure Transient - Ice Melted (McGuire Nuclear Station) 1.tE06=

1.4E+06 1 1 1 1

S.GE+05 _=__zz<HIII

-zoEi06

-1 0

.0 I

10 10 10-O 1---O Time SeCOndS)

(

Reference:

- McGuire Nuclear Station Updated Final Safety Analysis Report, Revision 10114100, Chapter 6, Figure 6-12J)

Page 8 of 14

B.

Provide a sample referenced Final Safety Analysis Report (FSAR) by giving a specific section in the FSAR for a specific plant.

Resoonsc As noted in the topical report References section (pages R-l and R-2, references 14 through 18),

for each of the five domestic ice condenser plants the applicable specific UFSAR sections describing blowdown phase ice bed DBA response are:

Duke Energy Corp., McGuire Nuclear Station Updated Final Safety Analysis Report, Revision 10/14/00, Section 62.1.13, 'Loss of Coolant Accident Design Evaluation."

Applicable figure is Figure 6-12, "Peak Containment Pressure Transient - Ice Melted."

Duke Energy Corp., Catawba Nuclear Station Updated Final Safety Analysis Report, Revision 4/8/00, Section 6.2.1.1.3, 'Loss of Coolant Accident Design Evaluation."

Applicable figure is Figure 6-10, "Peak Containment Pressure Transient - Ice Melted."

Tennessee Valley Authority, Sequoyah Nuclear Plant Updated Final Safety Analysis Report, Revision 514t98 (Rev. 14), Section 6.2.1.3.A, "Containment Pressure Transient -

Long Tern Analysis." Applicable figure is Figure 6.2.1-19, "Sequoyah Units I & 2, Containment Integrity Analysis."

Tennessee Valley Authority, Watts Bar Nuclear Plant Updated Final Safety Analysis Report, Amendment 2, Section 6.2.1, "Containment Functional Design." Applicable figure is Figure 6.2.14, "Melted Ice Mass."

American Electric Power Co., Donald C. Cook Nuclear Plant Updated Final Safety Analysis Report, Revision 17.0, Section 5.3, "Ice Condenser," and Section 14.3.4, "Containment Integrity Analysis." Applicable figure is Figure 14.3.4-10, "LOCA Mass and Energy Release Containment Integrity Ice Melt Transient".

5.

Page I-1, 4h paragraph of the repolt stated that the minimum blowdown ice mass is required to prevent a "bum-through" of the ice bed. This could cause a chimney effect in one or more ice condenser bays, thereby providing a path for steam to bypass the ice in the bed and get into the upper containment without being condensed. The Ice Condenser Utility Group (ICUG) established the minimum ice mass requirement based on the minimum ice mass required during "blowdown" phase of a postulated accident.

Why is the minimum ice based on the blowdown phase (<50 sec) only, instead of throughout the course of the accident? The peak containment pressure occurred much later (>1000 sec) than the end of blowdown foUowing a design basis loss-of-coolant accident in an ice condenser containment. The "burn-through" could happen after blowdown phase and could affect the peak containment pressure. If ICUG assumes that post-blowdown bum-through has no impact on the peak containment pressure, please justify this assumption by analyses or testing data. A simple statement in the topical report and in the proposed TS Bases is not sufficient.

Respose The proposed surveillance requirements provide two distinct ice mass requirements. The individual basket minimum blowdown ice mass is derived from the plant's safety analysis and is applicable to each individual basket The total quantity of ice mass is also derived from the plant's safety analysis and is applicable to populations of baskets. The Radial Zone total ice mass requirements provide assurance that the total ice mass resident within radial sections of the ice bed is consistent with the safety analysis. The individual basket minimum (i.e., minimum blowdown limit) provides assurance that individual basket mass will not be depleted during the initial blowdown. The total ice mass requirement provides assurance that the ice condenser has an adequate energy suppression capability to limit the long-term peak containment pressure.

The containment analyses are performed for two distinct periods. The blowdown period is addressed within the short-term contaimnent pressurization analysis (1MD). The containment integrity analysis is addressed within the long-term LOTIC analysis (for the Duke plants, the long-Page 9 of 14

term analysis is addressed by the GOTHIC model which substantiates the LOTIC results). A large variation in the ice mass stored within ice baskets is an ice mass maldistnton, and effectively represents a potential burn-through" scenario. As previously descnbed, there is a limited (actively managed) variation in the mass within any ice basket Variation in the blowdown flow entering the ice condenser is a blowdown maldistnbution, which represents another potential "burn-through" scenario. Both of these types of maldistnbution result in a non-uniform depletion of the stored ice mass. Ice condenscr maldistribution is a parameter in both the TMD and LOTIC analyses of containment response. Within both the TMD and the LOTIC analyses of containment, the ice condenser is modeled as six individual vertical segments.

As previously descnbed, the response of the ice condenser to the DBA was predicted by analysis and testing. During the initial design and licensing of the ice condenser containment concept, the effects of maldistribution (leading to early "burn-through") were investigated and reviewed. These reviews are documented within topical WCAPs and in the licensing bases for D.C. Cook Nuclear Plant (the first ice condenser), including those WCAPs previously listed within the response to question #4A, and also WCAP-8077, 'Ice Condenser Containment Pressure Transient Analysis Methods," April 1973. The latter report contains details regarding the Transient Mass Distnbution (TMD) code short-term analysis and analytical models, as well as Waltz Mill test comparisons.

Related documentation in the D.C. Cook FSAR, Appendix J, "Ice Condenser Containment Independent Analysis Program - Final Report," dated April 1972, includes an independent review of the ice condenser containment concept for the D.C. Cook design as well as a review of the Sequoyah, Watts Bar and McGuire designs.

A maldistribution factor was used within both the short-term and long-term containment analyses.

The maldistribution factors are input into the LOTIC analysis and are derived from the TMD analyses. Two maldistribution factors, blowdown maldistribution and post-blowdown maldistribution, are calculated for each of the six ice bed analytical sections. Blowdown raldistribution is the maldistnbution that LOTIC uses during the blowdown period. The duration of the blowdown period is from the instant of a loss of coolant accident until the end of blowdown.

The post-blowdown maldistribution is an input into the LOTIC analysis to define the flow distnbution into the various ice bed sections during the long term energy release period. This period starts at the end of the blowdown and includes the energy release from core reflood and decay heat generation to the end of the accident The LOTIC analysis uses flow distnbution into the six analytical sections of the ice bed as input Maldistnbution specified the fraction of the total flow entering an ice condenser section and is used to determine flow distnbution. (Reference Cook Plant FSAR, Appendix N, Question 11, Amendment 45, dated July, 1973)

Maldistnbution in the post-blowdown period can result in a lower peak containnent pressure. If the individual sections of the ice condenser melt unevenly and form channels for decay heat to pass through the ice bed into upper containment, the upper containment spray system can condense this steam and, thus, preserve the remaining ice for a longer period of time. When the other ice bed sections burn through later in time, decay heat boil-off has decreased and, therefore, the peak calculated containment pressure will decrease.

6.

Technical Specification Travelers Form, TSTF-429, proposed B Surveillance Requirement 3.6.15.2, Insert D, 3d paragraph states that any method chosen by the licensee will include procedural allowances for the accuracy of the method used. Please explain the "procedural allowances." Is there any calibration requirement included in the procedures for the nethod chosen?

Response

In designing the proposed ice ass surveillance requirements, ICUG determined that in order to adequately address the fact that certain ice baskets naturally become stuck (and therefore not liftable by conventional means), methods for deternining the mass of these stuck baskets must be Page 10 of 14

utilized. Since these methods of measurement would be intended to satisfy a surveillance requirement, the aror involved in these techniques must be quantified and documented in accordance with IOCFR50, Appendix B criteria. As such, there wil be procedural allowances made for any methodology used in determining ice basket mass for the proposed surveillance, whether it is done by direct lifting, ICEMAN' projection, or Visual Inspection.

Chapter I of the topical report discusses the approach Licensees wil take in addressing the procedural allowances for a given technique. For Manual Lifting (as with a lifting ng), calibration against a standard is ongoing industry practice. For alternative niethods, such as ICEMANW projection or Visual Inspection, documentation of historical data obtained using the method benchmarked against more accurate methods (i.e., lifting) will serve to identify random error values associated with the procedure. Over time, the accumulation of this data (and more experience with the technique) should show a decreasing random error value, which will in turn reduce the procedural allowance that must be made to account for it in the deternination of total ice mass.

Since the limited conditions for operability defined in the proposed ice mass surveillance requirements identify only the minimum (i.e., design basis) quantities of ice mass needed, allowances for measurement error must be made on a procedural basis and tied to the statistical analysis of the overall ice bed.. Chapter M of the topical report addresses the use of different mass determination techniques with different error values in the statistical analysis.

7.

On page v, under Sampling without replacement. the use of the term "sample population" is misleading. The leading sentence could be improved by wording as: "Taling samples from a parent population wherein each basket in the population can appear only once in the sample." Use of the term "sample population" persists throughout the topical report; consider revising it.

Resonse The term "sanple population", as used in this topical report, was intended to convey the fact that in the proposed ice mass surveillance requirement sampling plan, a sub-population of at least thirty sample ice baskets is randonly selected for statistical analysis from aparentpopulation (in this case, the 648-basket parent population being defined by a three-row Radial Zone). This wiU be clarified in the topical report.

8.

Table 2-l ves statistics as obtained from 9,470 measurements by ICEMANTW and shows that ICEMAN19, on the average, underestimates the true weight (measured by lifting) by 13 lbs.

Because underestirates are conservative, they are acceptable. However, Table 2-1 should give a breakdown by radial row, as different radial rows typically have different means and, perhaps, different standard deviations.

Resoonse The data contained in Table 2-1 is labeled "Reference Only" and intended for illustrative purposes, to compare the different mass determination methods and show the relative accuracy of the different methods. Plant specific data nay be different from this Table. Based on the reviewer's comnents, the data used to develop Table 2-1 was re-analyzed to determine the mean difference and standard deviation between ICEMAN' and manual lifting determined by row. There are several conclusions drawn from this re-analysis of the data used for Table 2-1:

The mean difference between the ICEMANTm and manual mass determination techniques remains negative (i.e., conservative) over all of the Radial Rows in the ice bed.

The mean difference gets closer to zero in Rows 2 - 6 (ie., less negative), since in these rows the ICEMAN' prediction is closer to the actual mass, and the mean difference becomes larger (more negative) towards the Containment and Crane Wall (rows I and 9, respectively).

Page 11 of 14

E The standard deviations in Table 2-1 evaluated by row show a similar distribution to that of the mean; Le, the standard deviation is closer to zero in the middle rows of the ice bed (Rows 2 - 6) because the ICEMANN" code predicts the actual masses better, and the standard deviation increases as the rows move outward toward the Containment and Crane Wall.

9.

On Page 11-2, in the middle of the page under the radical sign, X. should be X;, an obvious misprint. Similarly, following the radical sign, change X. to X; and n-th sample to i-th sample.

Resoonsc This change will be made in the topical report

10.

Page 111-2, last paragraph, is too vague. When is it appropriate to use Equation 3.1 or 3.2? How low must the accuracy be before Equation 3.1 is insufficient and needs to be replaced by Equation 3.2?

Rcsoonse For the purposes of the proposed surveillance requirements, the 95% confidence interval is one -

sided; i.e., only the lower bound (resulting in the lowest total estimated ice bed mass) of the interval is recognized in Equation 3.1 and Equation 3.2.

The expressions (Equation 3.1 and Equation 3.2) identified in Chapter III of the topical report represent two statistically valid approaches to establishing the 95% confidence mean (jl.) of a randomly selected sample of ice baskets. Equation 3.1 is the simpler approach, accounting for l

• accuracy in the measurement of individual basket mass directly, and also via the standard deviation of the sample mean. Equation 3.1 can be used even if the accuracy involved in the measurement of individual basket mass is low; in the case of ice condenser maintenance (as described in the topical report), this approach may result in unreasonably conservative (i.e, low) estimates of basket mass and add unnecessary work scope to an outage through the need for expanded sampling. Since one of the goals of the proposed ice mass surveillance requirements is to remove unnecessary conservatism and prevent differing interpretations of TS compliance in the industry, Equation 32 was developed as a follow-on to Equation 3.1, accounting for individual basket mass measurement error via a more refined methodology which allows the use of different mass determination methods (with different accuracies). While the approach used in Equation 3.2 still partially accounts for measurement error through the standard deviation (as in Equation 3.1),

by accounting for individual basket mass accuracy in the error of the mean the resulting 95/

confidence sample mean is more realistic, which provides a more consistent industry basis for assuring TS compliance. Tbis can be seen in the results of the example analysis of a hypothetical ice bed (see topical report Table 3-2).

For the purpose of compliance with the proposed total ice mass surveillance requirements, which includes the use of different.methods of ice basket mass determination and different measurement accuracies, Equation 32 will be the methodology implemented.

it.

On page III-3, under Sample Size. the first parenthetical statement is inappropriate. There are several distributions that are bell-shaped and symmetric but are not normal.

Resnonse The parenthetical statement will be removed in the topical report.

12.

On page III-7, under Note 2, below Table 3-1: if the error values are not equal to one-sigma, then what are they? Also Note 2, below Table 3-1, states that the given measurement random error is not the standard deviation. So, what is it?

• Change per ICUG-001, Revision I (Reference 20)

Page 12 of 14

Resoonsc The error values given in Table 3-1 of the topical report (and in Table 2-1, from which they are recalled) are illustrative in nature and not intended to reflect actual plant-specific error values. For this reason, the tables were identified as 'Reference Only" in the report The values shown in the tables were generated (for the purposes of the topical report) from industry databases and represent, in addition, a general 'comfort level' with a given mass determination technique. For example, the data for ICEMAN' resides primarily with the Duke Energy plants, since this technology has existed at those plants for a longer period of time. In the case of Visual Inspection, the TVA plants have more experience and actual data. From the compiled industry data that currently exists, the one-sigma values for the ICEMAN'm and the Visual Inspection mass determination techniques are about [691 lb and [177 1lb respectively, as noted in topical report Table 2-1. Upon implementation of the proposed surveillance requirements, procedural allowances made for random error will be documented formally at each plant as descnbed in the response to question #1B.

13.

Table 3-1, page I1-7, gives the standard deviation for visual inspection random error as 300 lbs.

This standard deviation is 20 times larger than that for the manual lifting. Since most measurements usually are within two standard deviations of the mean, the visual inspection would not appear to provide the necessary confidence level in meeting the 1071 lb minimurn, single basket weight criterion. Please discuss why the visual inspection method is a viable option in determining ice nass.

Response

The ertor values given in Table 3-1 of the topical report (and in Table 2-1, from which they are recalled) are illustrative in nature and not intended to reflect actual plant specific error values. For this reason, the tables were identified as "Reference Only' in the report. In addition, the confidence level is preserved by the use of a one-sided interval (as described in Chapter III of the topical report), which always reduces the mass of a given sample ice basket.

The values shown in the tables were generated (for the purposes of the topical report) from industry databases and represent a general 'comfort level" with a given mass determination technique. For example, the data for ICEMAN' resides primarily with the Duke Energy plants, since this technology has existed at those plants for a longer period of time. Consequently, the error applied to this technique at those plants is *[40] lb, which is slightly lower than the industry-generic standard deviation reported in Table 2-1 of the topical report In the case of the Visual Inspection technique, the TVA plants have more experience and actual data; the reported standard deviation is [177] lb based on this (again, from Table 2-1). The assumed random error of i[300] lb is a general value based on little Visual Inspection technique data. Additional use of this technique may allow the error in this type of measurement to be reduced. Again, for the purposes of the topical report, the values for assumed random error are intended to be illustrative, outlining the concept of alternate mass determination techniques as opposed to describing a finalized value. It is the intent of Licensees to frequendy optimize the mass determiation process for ice baskets, requiring that the standard deviations be adjusted for newly obtained data.

Since the proposed ice mass surveillance requirernents no longer contain an individual ice basket mass limit (other than the minimurn blowdown ice mass limit), but rather assure that total ice mass linited conditions for operability are met via the mean mass of the ice baskets in a given Radial Zone, the lower accuracy of the Visual Inspection technique is not as directly significant when used on a fraction of a given Radial Zone sample. However, if this methodology is to be utilized more extensively in assessing ice bed mass for the surveillance, this low accuracy nay result in expanded sanples in certain Radial Zones (see response to question #14), and due to the inherent conservatism of the method ray also cause a given Radial Zone to fail (perhaps unnecessarily) the surveillance altogether. For this reason, plant-specific ice basket mass deternination techniques will likely become more accurate over time; this in turn will necessitate increasingly accurate as-found ice basket mass data.

Page 13 of 14

14.

On page I-1S, Table 3-5, under lce Mass Samolina Plan Recomnendations, the recommendation for item 3, on sample expansion, is open to different interpretations. The recommendation should state the exact sample size expansion when one, two, orx number of light baskets are found.

Response

The proposed ice mass surveillance requirements directly distinguish a potentialy deficient individual ice basket through the minimun required blowdown ice nass. As described in the topical report, any basket found to be below the minimum blowdown ice mass limit (approximately [400] lb, depending on the plant) is considered inoperable and requires entry into the TS Remedial Action. In this event, an expanded sample is not aBowed to exit the surveillance.

The statetent referred to in the topical report under Ice Mass Sampling Plan Recommendations, however, does relate to expanding the sample in a Radial Zone if the initial 30-basket sample analysis shows the mean ice mass per basket wil not support the total ice nass requirement for that Zone. In effect, this approach allows Licensees to expand the sample beyond the initial 30 baskets (including eventuaUy expanding it to encompass all baskets in the Radial Zone). If sufficient ice is not present to neet the Radial Zone ice mass requirements when all ice baskets in a Zone are included in the analysis, then the TS Remedial Action must be entered (for a schematic of the overall process, see Figure 0-1 in the topical report).

The topical report (Chapter III) descnbes the reasoning associated with the proposed surveillance requirenent's definition of a 30-basket sample. Utilizing the stratified sampling approach, the ice bed was divided into three distinct radially-oriented ice basket populations, as opposed to a single population including all ice baskets, as is currently done. Because the ice baskets in the ice bed tend to sublimate over an operating cycle at different rates (some significantly), treating the entire ice bed as a single Zone could subject the 95% confidence sample analysis to higher standard deviation values, and consequently increase the error of the mean. As Figure 3-2 in the topical report shows, for sample sizes more than about 30 baskets, the error of the mean term in the 95%

confidence analysis levels out. By establishing a 30-basket sample size in each of three Radial Zones the net effect is to sample the entire ice bed with a sample size of 90 baskets, with each 30-basket radial subset focused on ice baskets that experience similar sublirnation rates. Using this stratified sampling approach, standard deviation values are specific to Radial Zones, more closely tied to actual ice basket mass behavior, and as a result the accuracy of the 95% confidence mean is increased. It can be noted that a 95% confidence level in the Radial Zone mass could be achieved with fewer samples; however, as the number of samples decreases, the error of the mean term in Equations 3.1 and 3.2 increases. Since this term always reduces the 95% confidence mean (pi.)

for the mass analysis (for surveillance purposes, the interval is one-sided), it effectively reduces available ice mass for satisfying the surveillance. The industry chose a sample size for each Radial Zone that balances the accuracy of the Zone mass analysis and the amount of physical effort required to achieve it.

In general, since the 30-basket sample size in each Radial Zone is adequate to assure 95%

confidence, the expanded sample, if it is required, can be any increased size the Licensee deems necessary based on the data obtained in the initial sample. For example, in the unlikely event that an initial sample shows a deficiency of ice in Radial Zone A in excess of the expected sublimation, an anomaly would be indicated, and a large expanded sample would be the prudent response to ensure the minimum ice mass requirements for the Zone are met and to assist in isolating the nature of the anonaly.

The topical report did not specify an exact procedure for expanding the sample, focusing instead on the statistical validity of the concept of expansion as necessary to achieve the intent of the proposed surveillance requirements; i.e., ensuring that adequate ice mass is present for the ice bed to perforrn its safety function. In industry practice, plant specific procedures controlled by IOCFR5, Appendix B and IOCFR50.59 will document the expansion process itself.

Page 14 of 14

1= Duke Duke Power 1~~~~~7

~~~~~~P o w er~~~~~~~~~~~

~Energy Cc tcCr AD&Po wer.

PrO. BOx 1006 Ch2locte. NC 28201-1006 October 10, 2002 U. S. Nuclear Regulatory Commission Washington, D. C. 20555-0001 Attention: R Heman (addressee only)

Subject:

Responses to Follow-up Questions on Ice Condenser Utility Group Topical Report No. ICUG-001, Rev. 0: Application of the Active Ice Mass Management Concept to the Ice Condenser Ice Mass Technical Specifi cation, and TSTF-429, Rev. 0 (TAC Nos. MB3379 and MB3938)

Gentlemen:

On September 18, 2001, the Ice Condenser Utility Group (ICUG) submitted the subject Topical Report ICUG-001, Rev. 0 to the NRC for review and approval. Subsequently, the NEI Technical Specification Task Force submitted related TSTF-429 to the NRC for approval as well. By letter dated May 16, 2002, the NRC staff provided questions (RAI) regarding the subject Topical Report and TSTF-429. By letter dated June 12, 2002, ICUG submitted formal responses to the RAI, and follow-up telecons between the staff and ICUG on August I and August 13, 2002 identified and resolved several issues related to that submittal. On October 1, 2002, several additional issues requiring resolution were identified by the staff on a telecon with ICUG.

The enclosed information serves to resolve the issues identified by Mr. Dan Lurie on the October 1, 2002 telecon. The issue identified by Mr. Chang Li on the telecon will be resolved and submitted under separate cover.

The Topical Report will be revised and re-issued upon receipt of the Safety Evaluation Report to incorporate those revisions described in this enclosure and the previous ICUG submittal dated June 12, 2002, as appropriate.

If you have any questions or need additional information, please contact the undersigned at (704) 382-3970 or rslvtton(duke-energ.com.

Sincerely, R. S. Lytton Chair, Ice Condenser Utility Group Enclosure xc(w/enclosure): Ron Heman (addressee only, 10 copies)

Document Control Desk (one copy)

Enclosure Responses to Staff Request for Additional Information Identified on October 1, 2002 via Telecon with ICUG Representatives Topical Report ICUG-001, Rev. 0 and TSTF429, Rev. 0 General Comment:

On the October, 2002 telecon with Ice Condenser Utility Group (ICUG) representatives, NRC staff outlined remaining issues with the TSTF429, Rev. 0 submittal involving the Plant Systems Branch review and the Office of Management & Budget (statistics) review. Resolution of the issue presented by the Plant Systems Branch reviewer will be sent under separate cover; this enclosure serves to address the issues presented by the OMB reviewer.

I.

The response to RAI item #10 in the June 12, 2002 ICUG RAI response submittal indicates that Equation 3.1, as presented in Chapter III of the ICUG-00 1, Rev. 0 topical report, is more conservative than Equation 3.2. This is not a correct statement based on the information presented; Equation 3.2 is actually more conservative.

Response

The reviewer's statement is correct. The RAI response to item #10 will be revised and this revision reflected in the final version of the ICUG-001 topical report, to be submitted after receipt of the SER.

2.

The responses to RAI items #8, #12, and #13 in the June 12, 2002 ICUG RAI response subrnittal indicate that the information presented in Tables 2-1 and 3-1 are illustrative in nature and not intended to reflect actual plant-specific values. Can ICUG provide more realistic values for these tables?

Resnonse The values given in the referenced tables are labeled as illustrative (reference only) in the ICUG-001, Rev. 0 topical report because actual data does not yet exist at all plants. The information provided in the topical report represents data from plants that have done some limited preliminary work in projecting ice basket nass. ICUG is requesting staff approval only of the methodology being employed to project ice basket mass; as data and experience are gained, the plant-specific procedures that govern this methodology will be updated. It is expected that the procedures will be revised frequently to include recent ice basket mass data, which will serve to refine the processes further.

3.

The response to RAI item # 14 in the June 12, 2002 ICUG RAI response submittal indicates that the minimum sample size for each Radial Zone is 30 baskets. There is no stated provision for what Licensees will do when a 'light" basket is discovered during the surveillance. The original surveillance requirement provided for a 20-basket penalty expansion if a "light" basket was discovered. In the ICUG proposal, if the initial 30-basket sample in a Radial Zone does not meet the surveillance limit, then a continuously expanding sample (up to and including all baskets in the Radial Zone) would be allowed until such time that the surveillance limits are either met or the Licensee determines that the limit is not met. This approach does not seem appropriate; after the first 30-basket sample has been analyzed and determined to be deficient, some doubt has been cast on operability, and by continuously expanding the sample the Licensee is simply increasing the Page of 3

chance of an acceptable result. In addition, allowing a continuously expanding sample seems to allow Licensees an indefinitc amount of time to determine if an operability concern exists. The follow-up process for the sample expansion needs to be addressed.

Response

The reviewer's concern is noted. As described in the June 12, 2002 ICUG RAI response, there is no longer a definition for a "light" ice basket. When reviewing the originally-provided surveillance requirement for potential revisions, ICUG realized that 'light" was too vague a description since it essentially allowed a basket to be empty (i.e., "light" could mean zero mass) as long as baskets in the immediate vicinity (i.e., same Bay) had sufficient mass to counter the effect of the empty one through the calculation of the sub-population mean. The ICUG-proposed surveillance requirements define a deficient individual ice basket only as one who's mass is below the minimum blowdown ice mass limit (approximately [400] lb, depending on the plant). ICUG considers this a significant improvement since it better aligns with safety analysis in assuring the prevention of ice bed bum-through during the blowdown phase. Similar to the aforementioned original surveillance requirement, the ICUG-proposed SR defines the mean mass limit per basket (approximately [1207] lb) to determine overall operability, with no basket's ice mass in the sample group allowed to be less than [400] lb.

Under the ICUG-proposed SR, upon analyzing the as-found 230-basket sample in a Radial Zone Licensees will be allowed to assess whether a larger sample is required to satisfy the operability limit. Given the larger error-of-the-mean tern for 95% confidence and the one-sided interval, this approach appears prudent since the initial sample would be a conservative indication of the condition of the ice bed. As noted in the RAI response to item #14, ICUG chose a sample size that balanced the accuracy of the mass analysis and the physical effort required to achieve it.

Current industry practice also indicates that this assessment could be made with the plant on-line (i.e., in advance of a refueling outage). Given this scenario, the reviewer's concem with the unbounded assessment period has merit. In order to address this concern, ICUG discussed the focus of future Ice Mass Determination SR procedures, and in so doing referred to existing regulatory direction.

Under the guidance of Generic Letter 91-18:

I.- If the Licensee chooses initially not to declare a system inoperable, the Licensee must have a "reasonable expectation that the system is operable and that the prompt determination process will support that expectation."

When operability verification or other processes indicate a potential deficiency or loss of quality, Licensees should make a prompt determination of operability and act on the results of that determination.

It is inportant to note that performance of the Ice Mass Determination SR is not a test, but rather an inspection to deternine the existing ice bed condition. A sample expansion is not a retest, but a measure to increase the scope of the inspection. In the case of the ice bed, existing industry operating experience has shown that it is highly unlikely conditions warranting an expanded sample would be needed.

Once the ICUG-proposed ice mass deterrination SR procedure is entered (perhaps on-line), an ongoing assessment of operability is in effect being performed. While the specific procedures for performing the new surveillance will vary from plant to plant and have yet to be finalized, it is the intent of the industry to adhere to the following sequence:

I.

Enter the surveillance procedure for ice mass determination.

2.

Upon analysis of the initial randomly-selected sample ice basket group, determine if the SR limit has been met.

3.

If the SR limit has been met, complete the surveillance procedure.

Page 2 of 3

4. If the surveillance limit has not been met, perform an inmediate assessment of operability per GL 91-18 guidance.

5. If a basis for a reasonable expectation of operability exists and completion of sample expansion can be completed promfptly, expand the sample group as appropriate to complete the surveillance procedure.

6. If a reasonable assurance of operability no longer exists or prompt deterrnination is not possible, immediately declare the ice bed inoperable and enter the appropriate Technical Specification Remedial Action.

Page 3 of 3

M1k Duke Duke Power UWPov/er~~~~~~~~~~~~~~~~~~~~

~~526 South Church Street fawower.

P.O. Box 1006 Charlott. NC 28201-1006 October 22, 2002 U. S. Nuclear Regulatory Commission Washington, D. C. 20555-0001 Attention: R Heman (addressee only)

Subject:

Responses to Follow-up Questions on Ice Condenser Utility Group Topical Report No. ICUG-001, Rev. 0: Application of the Active Ice Mass Management Concept to the Ice Condenser Ice Mass Technical Specification, and TSTF-429, Rev. 0 (TAC Nos. MB3379 and MB3938)

Gentlemen:

The information submitted herein is being provided in response to requested additional information regarding the review of Ice Condenser Utility Group (ICUG) Topical Report No. ICUG-001, Rev. 0, Application of the Active Ice Mass Management Concept to the Ice Condenser Ice Mass Technical Specification, and TSTF-429, Revision 0. This request for information was communicated by Mr. Chang Li via a telephone conference on October 1, 2002. Responses to other requests for information from the October 1, 2002 telephone conference are provided under separate cover letter dated October 10, 2002.

The response is provided as Enclosures I and 2 to this letter, and serves to supplement the information submitted by ICUG via fax on August 22, 2002. This response addresses a question which ICUG elected to answer utilizing Duke Energy Corporation (Duke) analysis capabilities. Duke is providing this information as a member of the ICUG, and as such the enclosed information is available to resolve questions that are applicable to all domestic ice condenser containments.

If there are any questions or if additional information is needed on this matter, please contact the undersigned at (704) 382-3970 or rsltton(d,duke-energy.com.

Sincerely, R. S. Lytton Chair, Ice Condenser Utility Group Enclosures xc(w/enclosures):

Ron Heman (addressee only, 10 copies)

Document Control Desk (one copy)

Responses to Staff Request for Additional Information Identified on October 1, 2002 via Telecon with ICUG Representatives Topical Report ICUG-001, Rev. 0 and TSTF429, Rev. 0 General Comment:

On the October 1, 2002 telecon with Ice Condenser Utility Group (ICUG) representatives, NRC staff outlined remaining issues with the TSTF-429, Rev. 0 ICUG submittat involving the Plant Systems Branch review and the Office of Management & Budget (statistics) review. Resolution of the issues presented by the 0MB reviewer has been sent under separate cover, this enclosure serves to address the issue presented by the Plant Systems Branch reviewer.

Ouestion The question is a follow-up issue concerning the effects of early ice bed burn-through on the peak containment pressure after the blowdown phase of a design basis loss of coolant accident. The original issue is documented in the NRC RAT dated May 16, 2002 (reference item #5). Generic licensing basis information was referenced in the original ICUG response that describes analysis perforned for a post-blowdown ice bed maldistribution factor of 1.36.2 The results of this analysis show a peak containment pressure after total ice bed melt-out that is slightly lower than the peak containment pressure without ice bed maldistribution. Therefore, there is no adverse effect on peak containment pressure for a post-blowdown ice bed maldistnbution factor of 1.36.

This single-point (1.36) analysis appears to be inadequate because ice bed maldistribution may not be constant after the ice basket melt-through The dynamics of ice bed and steam flow maldistribution after blowdown need to be addressed.

The Final Safety Analysis Reports of D. C Cook, Catawba, and McGuire include a maldistribution factor design limit of 1.5. The dynamic conditions of melting ice during a design basis accident (DBA) need to address the potential for the maldistrbution factor to exceed the limit of 1.5.

The long term peak containment pressure for a significant maldistnbution (>1.36) is not known.

The design basis containment pressure for a1l ice condenser plants was based on a maldistribution factor of 1.0. The dynamic change of the maldistnbution following an ice basket melt-through, and the following related questions, need to be addrssed Is the naldistrbution factor going to exceed the design limit of 1.5, assuming an ice basket melt at the end of blowdown? If not, provide the basis in the calculation. If yes, what are the consequences?

Response

There are two types of nialdistribution addressed in this RAI. Ihe blowdown maldistnbution factor limit of 1.5 shown in the industry's FSARs is related to DBA steam flow into the ice condenser lower inlet door ports. This maldistnbution factor is based on steam flow and is

' Letter from R.S. Lytton to U.S. NRC, Responses To Questions Regarding Topical Report ICUG-001, Rev. 0 and TSTF-429, Rev. 0, dated June 12, 2002.

2 D.C. Cook Nuclear Plant Final Safety Analysis Report, Appendix N, Question 11, Amendment 45, dated July, 1973.

Page 1 of 3

determined by the physical configuratioa of the inlet door ports, and is not affected by the scope of changes oCTSTF-429, Revision 0. However, concerns regarding a blowdown naldistribution factor in excess of 1.5 are addressed by the GOTHIC code sensitivity run results provided in this response.

The second type of maldistnbution concerns areas of ice mass deviation within the ice bed, which is a mass distribudon issu'e. The ICUG-001, Rev. 0 Topical Report and TSTF-429, Revision 0 propose a combination of a minimum ice mass limit per basket and a documented active mass management philosophy govemed by IOCFR50, Appendix B to assure adequate distribution of ice exists. Given this approach, large areas of extreme ice mass deviation are not credible; however, it is helpful to show analytically that containment pressure response is not significantly sensitive to extreme mass deviations to further support the information presented in the topical report and the TSTF. Included in this response are GOTHIC code sensitivity run results for McGuire that provide insights into the performance of the ice bed when lIrge areas exist with extreme deviations.

The GOTHIC code is the current license basis analysis methodology for Duke Energys Catawba and McGuire ice condenser containment designs. It is a three-dinensional analysis code that accurately models both the mass-energy release location relative to the configuration of ice condenser door inlet ports and the ice mass contained within defined sections (nodes) of the ice bed. The GOTHIC code does not require input of steam flow or ice mass deviation maldistribution factors, as does the original LOTIC code analysis. Therefore, the blowdown and ice mass deviation raldistribution concerns are addressed by locating the DBA mass-energy release closest to the section modeled with an ice mass deviation.

The sensitivity cases docurented in Enclosure 2 examine the effect of ice mass deviations which are allowed within the Technical Specification requirements available through adoption of an approved TSTF-429, revision 0, but are beyond a credible condition that could develop. The proposed Technical Specification requirements segregate the ice bed into three Radial Zones that correspond to historical sublimation characteristics. The proposed requirements ofTSTF-429 will necessitate that plant-specific ice nass management policy monitor the ice in each basket to maintain the required mean mass that supports the total ice mass requirements for these Radial Zones defined by the Technical Specification. There are no known mechanisns during normal operation that could reasonably be expected to result in extreme sublimation of ice nass in a large-scale localized region of a Radial Zone. Active ice mass management practices will typically cause the mean mass of localized populations of baskets in a Radial Zone to converge to a value supporting the Technical Specification requirement. The sensitivity cases of ice mass deviation presented herein are beyond a credible condition as they represent all baskets in Radial Zone A across 2.75 bays sublimated to extreme conditions with the location of these deficient bays directly above the reactor coolant system break location.

The baseline case for the McGuire containment is a uniform ice bed load (ie., no deviation) with a mass equivalent to 973 lb per basket (mean). This represents the current design basis limit for ice bed operability (a total of 1.89 x 106 lb of ice in the bed). The frst ice mass deviation case reduces the ice in 2.75 bays of Radial Zone A (about 75 baskets) to 600 lb per basket each (approximately a 40/O reduction from the design basis), while maintaining the total ice mass in the bed the same.

The results of this sensitivity case show that containment peak pressure remains essentially unchanged.

For the second ice mass deviation case, the ice mass in the 2.75-bay sector of Radial Zone A is further reduced to 400 lb of ice per basket (approximately a 60% reduction from the design basis),

again maintaining the total ice bed mass the same. The results of this sensitivity run show only a minimal increase (0.29 psi) in McGuire's post-LOCA peak containment pressure. This is well within the station's design margins, and further demonstrates that ice bed performance is not significantly sensitive to even gross ice mass deviations.

The third ice mass deviation case extends this same maldistribution (400 lb of ice per basket) such Page 2 of 3

that all three Radial Zones (A, B, and C) in the 2.75-bay sector contain baskets reduced in mass, with the total mass of the ice bed remaining constant Ihis sensitivity mn, which represents a 225-basket gross mass deviation in a localized area positioned direcdy above the postulated DBA pipe break, shows essentially the same resullt the peak post-LOCA containment pressure increased only 0.06 psi over the second sensitivity case. The results of the third sensitivity case show that a threefold increase in the number of reduced-mass ice baskets above the break location results in essendally no change in the containment response to the limiting large-break LOCA.

In conclusion, the extreme cases of ice mass deviation descnbed above and documented in demonstrate that the McGuire containment response is not significantly sensitive to ice mass naldistribution. The extreme ice mass deviation cases modeled here are intended to show that early melt-out of some sections of the ice bed does not cause significant changes in the containment pressure response.

Page 3 of 3

I Enclosurc 2 Responses to Staff Request for Additional Information Identified on October 1, 2002 via Telecon with ICUG Representatives Topical Report ICUG-001, Rev. 0 and TSTF429, Rev. 0 Genera Comment:

The following figures depict the results of the sensitivity runs descnbed in Enclosure 1. Boundary conditions for the uns were set based on the current McGuire licensing basis analysis as shown in the McGuire UFSAR. It is assumed that the initial total ice bed mass for all cases is unchanged from the current McGuire design basis analytical value of 1.89x 106 lb. These sensitivity runs portray the entire DBA LOCA transient from blowdown to beyond the containment peak pressure response that occurs after the ice bed melts out completely.

The first sensitivity run assumes that in Radial Zone A (Rows 7, 8, and 9), 2.75 bays of the ice bed located directly above the assumed break location (defined as Sector 1) contain an initial ice mass equivalent to 600 lb per basket. This represents a subdivision of the ice bed consisting of about 75 ice baskets, grouped together. The second sensitivity run assumes the initial ice mass in this same subdivision of Sector I is equivalent to 400 lb per basket The results of these runs are presented in Figures I through 9. Ice melt pattems (Figures 6 through 9) are depicted only for the first sensitivity case.

The third sensitivity run assumes that in all three Radial Zones (rows I through 9), the initial ice mass in the 2.75-bay Sector I is reduced to the equivalent of 400 lb per basket This represents a subdivision of the icc bed consisting of about 225 ice baskets, grouped together. The results of these runs are presented in Figures 10 -14.

Summary of results presented for McGuire:

Postulated Ice Mass Deficiency in Radial Zone A. Sector 1 Figure 1:

Containment Pressure Response Comparison Figure 2:

Upper Containment Temperature Response Conparison Figure 3:

Lower Containment Tcmperature Response Comparison Figure 4:

Containment Sump Temperature Response Comparison Figure 5:

Ice Mass Melt Comparison Figures &9: Ice Melt Patterns - 30 sec to 3600 sec Postulated Ice Mass Deficiency in All Radial Zones. Sector I Figure 10:

Containment Pressure Response Comparison Figure 11:

Upper Containment Temperature Response Comparison Figure 12:

Lower Containment Temperature Response Comparison Figure 13:

Containment Sump Temperature Response Comparison Figure 14:

Ice Mass Melt Comparison In Figure 1, the containment pressure for the first two sensitivity cases and the baseline case are presented. The containment pressure trends for the cases are very similar until after 3000 seconds, when the containnent spray source is switched from the ambient water of the Refueling Water Storage Tank to the warmer sump water. Due to the lower ice mass remaining relative to the baseline case, the containment pressure increase in the sensitivity case is slightly faster. The peak containment pressure in the first sensitivity case is 13.50 psig, reached at 6100 seconds. This is within 0.1 psi of the peak pressure reached in the baseline case (13.44 psig, reached at 6300 seconds). In the second sensitivity case, containment pressure reaches a peak value of 13.73 psig at 6000 seconds.

Page of 12

In Figures 2 and 3, the upper and lower containment average temperature profiles are khown. The upper containment terperature in the sensitivity cases show a sharp increase in the first S minutes of the transient due to the early melt out of the deficient Sector I ice baskets. This early melt out of Sector I has no impact on the peak containment pressure, which is reached after the ice bed is completely melted. The extreme ice mass deficiency nodeled in Sector I does contrbute slightly to the peak containnent pressure however, by reducing the length of time the ice bed exists during the entire transient Figure 4 shows the sumnp temperature comparison for the cases. Due to the slightly increased ice melt rate, the sensitivity cases have a lower suip temperature profile. The difference is as much as 3 F for much of the first hour of the transient. After the ice bed is melted, the sunmp temperature values converge.

In Figure 5, the total ice melt is plotted for the cases. The ice melt in the sensitivity cases is greater by as much as 60,000 lb to 90,000 lb through the first hour of the trassient This is due to the initial ice mass maldistribution modeled above the break in the sensitivity cases, causing greater steam penetration into the ice bed earlier in the transient This allows some areas of the ice bed to be exposed to steam earlier due to the cross-flow present within the ice bed.

In Figures 6 through 9, the ice bed melt patterns for the first sensitivity case are illustrated by shaded diagrams. For reference, a representative set of ice melt patterns for a uniform ice bed load (i.e., no maldistnbution) are included in DPC-NE-3004-PA, Rev. 1, Figures 5.4.1.1-6 to 5A.1.1-9.

The darker shading represents areas with nore ice present in that region of the ice bed (an ice volume fraction of >0.32 represents a fully loaded ice basket in Figures 6 through 9). The 75-basket subdivision of Radial Zone A in Sector containing the deficient ice baskets is completely melted out 450 seconds into the transient. Cross-flow of steam is evident, as well as some top-to-bottom melting. In general, the melting occurs from the innermost baskets (rows 7-9, in Radial Zone A) to the outermost baskets (rows 1-3, in Radial Zone C), and from the bottom of the baskets to the top.

Figures 10-14 show the results for the third sensitivity case, which extended the 400 lb/basket maldistribution to all of Sector l. The trends are similar to those of the second sensitivity case.

The peak containment pressure shown in Figure 10 is 13.79 psig, which is only 0.06 psi higher than the second sensitivity case. The temrperature and ice melt profiles are also very similar.

Page 2 of 12

MNS LOCA Containment Response RSG Cold Leg Pump Discharge Contalment Pressure - Comparison 0

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Figure 1 - Containment Pressure Response Comparison Postulated Ice Mass Deficiency in Radial Zone A, Sector I MNS LOCA Containment Response RSG Cold Leg Pump Discharge 200 1

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Rows 7-9 break Figure 8 MNS-1 Cold Leg Break Ice Melt Patterns - 1800 seconds Radial Zone A, Sector I - Initial Ice Mass at 600 lb/basket Page 8 of 12

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Rows 7-9 break Figure 9 MNS-1 Cold Leg Break Ice Melt Patterns - 3600 seconds Radial Zone A, Sector I - Initial Ice Mass at 600 lb/basket Page 9 of 12

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MNS LOCA Containment Response RSG Cold Leg Pump Discharge IE I

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1000 2000 3000 4000 5000 6000 Te (seconds) 7000 8000 sooo 10000 Figure 12 - Lower Containment Temperature Response Comparison Postulated Ice Mass Deficiency in All Radial Zones, Sector I MNS LOCA Containment Response RSG Cold Leg Pump Discharge 240 220 ZL 2M0 180 160 c 140 0,

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1000 2000 3000 4000 5000 6000 ime (seoonds) 7000 8000 mm00 10000 Figure 13 - Containment Sump Temperature Response Comparison Postulated Ice Mass Deficiency in All Radial Zones, Sector 1 Page 11 of 12

JIJL 07 2003 7:35 AM FR DIJKE ENERG'Y CORP704 32 3993 TO 13014151525 P. 02 MNS LOCA Containment Response RSG Cold Leg Pump Discharge 2.000.000 1.600.000 1.600,000 1.400,000 3 1.200,000 -

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D Duke Duke Power ESPower~

EncrgyCentcr A Dw&e Enov CwP-rny Charloute. NC 28201-1006 November 26, 2002 U. S. Nuclear Regulatory Commission Washington, D. C. 20555-0001 Attention: R. Heman (addressee only)

Subject:

Responses to Follow-up Questions on Ice Condenser Utility Group Topical Report No. ICUG-001, Rev. 0: Application of the Active Ice Mass Management Concept to the Ice Condenser Ice Mass Technical Specification, and TSTF-429, Rev. 0 (TAC Nos. MB3379 and MB3938)

Gentlemen:

The information submitted herein is being provided in response to requested additional information regarding the review of Ice Condenser Utility Group (ICUG) Topical Report No. ICUG-00 1, Rev. 0, Application of the Active Ice Mass Management Concept to the Ice Condenser Ice Mass Technical Specification, and TSTF-429, Revision 0. This request for infornation was communicated by NRC staff to ICUG via telephone conference on November 18, 2002. Responses to other requests for information have been sent under separate covers dated June 12, 2002; October 10, 2002; and October 22, 2002.

The response is provided as Enclosures 1 and 2 to this letter. Enclosure I details the revisions made to the ICUG-001, Rev. 0 topical report i i iraonse to the staffs RAIs and subsequent ICUG responses up to and including the November 18, 2002 telecon. details the proposed revisions to the TSTF-429, Rev. 0 submittal as a result of the November 14, 2002 public meeting and the November 18, 2002 telecon.

If there are any questions or if additional information is needed on this matter, please contact the undersigned at (704) 382-3970 or rslvttonQduke-errergv.com.

Sincerely,

~..4 R. S. Lytton Chair, Ice Condenser Utility Group Enclosures xc(w/enclosures):

Ron Heman (addressee only, 10 copies)

Document Control Desk (one copy)

Responses to Staff Request for Additional Information Identified on November 18, 2002 via Telecon with ICUG Representatives Topical Report ICUG-001, Rev. 0 General Comment:

On the Novemiber 18, 2002 telecon with Ice Condenser Utility Group (ICUG) representatives, NRC staff outlined renaining issues with the ICUG-01, Rev. 0 topical report NRC requested that ICUG make revisions to the topical report to reflect the industry's connitment to Active Ice Mass Management practices, in particular to affirm that Licensees will manage each ice basket above the required safety analysis mean, in lieu of managing each basket to the minimum individual ice basket mass. The following revisions to the ICUG-001 topical report, along with the proposed changes to the 'lTS

-429 package (see ), serve to accommodate that request. The revised topical report (ie., ICUG001, Rev. 1) will be submitted after the SER is written and has been incorporated.

Topical Report ICUG-O01 List of ChanEes to the July 2001 Version (rev. 0) to Produce the December 2002 Version (rev. 1)

1. Cover page updated to specify "Revision I and "December 2002".

2.

Page iii, Tables: Revised term 'sample population" to "saniple group" (two places) per reference 19.

3.

Page v, Nomenclature: Revised term "sample populations" to "sample groups" (three places). Revised definition of "Sampling without replacement" to reflect sinilar clarification, per reference 19.

4. Page 0-1, Active Ice Mass Management: Added following sentence at beginning of second paragraph- "Existing AM practices manage each ice basket in the ice bed above the required mean mass supporting the safety analysis." Change per reference 22.

5. Page 0-2j Industry Challenges: Revised term "sample population" to 'sample group" per reference 19.

6.

Page 0-3, Industry Challenges: Revised last two paragraphs to read: "A further disparity in the historical methodology required each statistically sampled basket to contain the specified amount of ice, while the Bases allowed for individual baskets to be "light" (ie, less than the technical specification required minimum mass) if baskets in the local area were sufficiently full. This contradiction also led to differing industry interpretations, even though the original intent was, as descnbed by the technical specification bases, to prevent localized gross degradation of the ice bed.

The technical specification methodology presented here treats this contradiction by recognizing that the two primary concerns of the ice mass design basis-and therefore the two required surveillances-are the presence of sufficient total ice mass in the bed distributed appropriately to accommodate the overall DBA response, and a sufficient minimum nass in any individual basket maintained to prevent localized areas of degradation that might challenge the DBA pressure response.

"The requirement for the overall DBA response is met by determining total ice mass in the bed based on a sampled group. In this manner, the word "each" is eliminated from the operability requirement, and individual baskets can sublimate during an operating cycle to whatever level their relative position in the ice bed dictates. Conversely, the minimum individual basket mass requirement stipulates a minimum mass of ice for each of the statistically sampled baskets so that a minimum amount of ice is Page 1 of 4

verified to be present The use of each in this instance is appropriate, since the containment analysis is primarily concerned with localized degradation and the sampled group is a valid representation of the entire Radial Zone under surveillance. As noted previously, AIMM practice will manage each basket above the required safety analysis mean, with no individual basket allowed to sublimate below the minimm basket mass value. AIMM practice does not manage individual basket mass to values below the required safety analysis mean." Changes per reference 22. Also revised term 'sample population" to "sample group" (two places) per reference 19.

7.

Page 0-3, Summary of Significant Aspects: Clarified that industry commitments to ranage the ice mass in each basket above the required technical specification mean, a statistically random sample in each Radial Zone, and a defined minimum individual ice mas per basket combine to become the basis for verification of appropriate ice distnbution in lieu of a limited azinuthal row-group surveillance, and deleted reference to minimum blowdown ice mass per reference 22.

8.

Page 04, Figure 0-1: Revised term in flow diagram "Blowdown Limit" to "Minimum Individual Basket Limit" per reference 22.

9. Page 0-5, Table 0-1: Revised fourth bullet to: "Surveillance requirements for both overall DBA response and minimum individual basket mass are defined." Revised fifth bullet to: "Operability determination for the overall DBA response is based on the total nass of the ice bed as estimated by a statistical random sample, as opposed to individual basket mass as determined by representative sample". Revised sixth bullet to: "Operability determination for the minimum individual basket mass is assessed for the bed based on individual sampled basket mass". Revised eighth buUet to: "Proper azimuthal distribution of ice in the ice bed is no longer assessed by a separate surveillance requirement; it is implemented through established industry-wide maintenance practices that manage each ice basket above the required safety analysis mean and confirmed through as-found random sampling techniques". Changes per reference 22.

10. Page 1-1, Design Basis: Revised second paragraph to differentiate between blowdown mass and minimum individual ice basket mass to prevent a localized region of mass degradation in the bed that might challenge the DBA pressure response. Added the following sentence to the end of the second paragraph to further develop the minimum basket mass concept "Utilizing this information and insights provided by Ref 21, the basis for a minimum individual basket mass requirement is formed, designed to prevent a localized area of ice bed degradation that might challenge the containment pressure response in either the short-term or the long-term phase of the DBA". Changes per reference 22.

11. Page 1-2, Design Basis: Revised parenthetical item 2 at end of paragraph to: "the ice mass is sufficiently distributed such that localized regions of mass degradation are not created in the ice bed",

per reference 22.

12. Page 1-2, Original Ice Mass Technical Specification Requirements: revised "sample population" to "sample group" (two places), per reference 19.

13. Page I-3, Original Ice Mass Technical Specification Requirements: Revised sentence under Figure 1-1 to read. 'In addition, these masses were used as the verification that a region locally deficient in mass did not exist in the ice bed that would challenge the DBA pressure response". Deleted reference to the long-term phase of the DBA in the last sentence on the page. Changes per reference 22.

14. Page 14, Historical Data Analysis: Revised term "sample population" to "sample group", per reference 19.

15. Pages 1-8 & 1-9,

Conclusions:

Revised second paragraph to read: "The minimum individual basket mass surveillance requirement is based on the minimum amount of ice needed in each basket to avoid localized regions of degradation in the ice bed that might challenge the DBA pressure response. This Page 2 of 4

limit is derived in part from testing performed by Westinghouse Electric Corporation at the Waltz-Mill Test Facility and in part from sensitivity runs performed using the GOTHIC analytical code (Ref 21).

Concurrent assurance that localized regions of gross degradation do not exist in the ice bed is given via Active Ice Mass Management (AIMM) methodology, which is based on current industry maintenance practice and asserts that the ice mass in each basket in the ice bed will be managed above the required safety analysis mean, and serviced prior to reaching this limit". Change per reference 22.

16. Page 1-9,

Conclusions:

Deleted reference to `blowdown" and replaced it with 'individual basket mass", per reference 22.

17. Page 11-3, Analysis and Comparison: To the last paragraph on the page, added the following: "It is also noted that for determination of plant-specific error values for any alternative technique, the industry approach would involve including two standard deviations of the mean in order to assure 95%

confidence in any individual measurement benchmarked against a more accurate method, such as a load celL These details will be documented in plant-specific procedures for each alternate method employed for the surveillance". Changes per reference 22.

18. Page II-5,

Conclusions:

Revised last sentence of fourth paragraph to read: "The random error accounts for the error associated with the various mass determination methods, and generally will represent two standard deviations of the mean", per reference 22.

19. Page 11-2, Ice Mass Statistical Strategy: Revised the term "sample population" to "sample group" (four places). Corrected mislabeled variable in equation for s and in definition of X. Change per reference 19.

20. Page E1-3, Ice Mass Statistical Strategy: Revised term "sample population to "sample group", per reference 19. Clarified in last sentence of first paragraph on the page that at least one standard deviation is needed for the determination of random error using this method, per reference 22.

21. Page 1II-3, Sample Size: Deleted the parenthetical statement "(the probability density function of which is a symmetric bell-shaped curve)", per reference 19.

22. Page 111-4, Sample Size: Revised term "sample population" to "sanple group" (five places), per reference 19.

23. Page m-5, Sample Size: Revised term "sample population" to "sample group" (two places), per reference 19.

24. Page m-7, Table 3-1: Revised Note 2 under the table to: 'The error values shown may not be equal to the one-sigma random error defined in Equation 3.2. Plant-specific procedures will determine the appropriate value to use in Equation 3.2 and will normally represent two standard deviations for any alternate nass determination method". Changes per reference 19.

25. Page EI-9, Alternate Basket Selection Strategy: Revised term "sample population" to "sample group", per reference 19.

26. Page III-10, Applications of Sampling Plan: Revised term "sample population" to "sample group" (four places), per reference 19.

27. Page II-I, Table 3-3: Revised term "sanple population' to "sample group", per reference 19.

28. Pages 111-12 through 111-15, Table 3-4: Revised term "sample population" to "sarple group" (four places, in title), per reference 19.

Page 3 of 4

29. Page R-2,

References:

Added the following sequentially numbered references, which document the Requests for Additional Information from the staff and the ICUG responses:

19. ICUG Response to NRC Request for Additional Information, R.S Lytton letter to NRC dated June 12, 2002 (w/enclosure).

20. ICUG Response to NRC Request for Additional Information, RS Lytton letter to NRC dated October 10, 2002 (w/enclosure).

21. ICUG Response to NRC Request for Additional Information, R.S Lytton letter to NRC dated October 22, 2002 (w/enclosures).

22. ICUG Response to NRC Request for Additional Information, R.S. Lytton letter to NRC dated November 26, 2002 (w/enclosures).

30. Page A-i, Appendix A: revised sample population" to sample group", per reference 19.

31. Added this list of changes to the back.

32. Added a list of attached ICUG-NRC correspondence to the back

33. Attached ICUG-NRC correspondence (references 19-22) to the back.

Page 4 of 4 Responses to Staff Request for Additional Information Identified on November 18, 2002 via Telecon with ICUG Representatives Proposed Changes to TSTF-429, Rev. 0 General Comment:

On the November 18, 2002 telecon with Ice Condenser Utility Group (ICUG) representatives, NRC staff outlined remaining issues with the TSTF-429, Rev. 0 submittal package. NRC requested that ICUG make revisions to the ICUG-001, Rev. 0 topical report to reflect the industry's commitment to Active Ice Mass Management practices, in particular to affirm that Licensees will manage each ice basket to the required safety analysis mean, in lieu of managing each basket to the minimum individual ice basket mass. The changes made to the topical report to address this issue (see Enclosure 1) affect the TSTF-429 documentation as well; the proposed TSTF revisions are outlined below. The official version of TSTF-429, Rev. I will be submitted through NEI.

TSTF-429, Proposed Changes for Revision I Revision Description This revision incorporates changes to provide additional clarification and resolve concems identified in request for additional information received from NRC staff. Also, the revision provides some editorial corrections.

The bracketed ice mass values in SR 3.6.15.2 and SR 3.6.15.3 are revised to current licensing basis values for an ice condenser plant (i.e., DC Cook). The TS Bases for SR 3.6.15.2 has been revised to clarify Licensee's goals for maintaining each ice basket above the requirements of TSs. The wording of SR 3.6.15.3 is revised to delete

'blowdown as the basis for the minimum ice mass value. Instead, the TS Bases for SR 3.6.15.3 darifies that the basis for the acceptance criterion is the minimum amount of ice needed to avoid any challenge to the DBA containment pressure response.

Section - 2.0 Proposed Changes Revise ice mass value in the first sentence of the first paragraph from 2,346,408 to 2,200,000.-

Delete the word blowdown' in second paragraph.

Delete the word "blowdown in sixth paragraph.

Section - 4.0 Technical Analysis Delete the word blowdown' in the fourth paragraph.

Page 1 of 4

Revise the last two sentences of fourth paragraph to state -

'A new minimum ice mass acceptance criterion is added for each of the ice baskets sampled. This new acceptance criterion (minimum ice mass for each basket sampled) ensures that a significant localized degraded mass condition of the ice bed does not exist The value of this acceptance criterion is based on the minimum amount of Ice needed to avoid any challenge to the DBA containment pressure response. The basis includes consideration of data from the original testing performed by Westinghouse Electric Corporation at the Waltz-Mill Test Facility, and sensitivity runs perforned using the GOTHIC analytical code."

Subsection - 5.1 No Significant Hazards Consideration Revise third paragraph of the response to question I - delete the words "during the blowdown phase."

Revise last sentence of first paragraph of the response to question 3 -

'The addition of a minimum ice mass acceptance criterion for each of the ice baskets sampled ensures the ice bed condition is consistent with the initial conditions of the DBA by limiting localized degradation to avoid any challenge to the DBA containment pressure response.'

Insert A Verify total mass of stored ice is > 12,200,000] lbs by calculating the mass of stored ice, at a 95% confidence level, in each of three Radial Zones as defined below, by selecting a random sample of > 30 ice baskets in each Radial Zone, and Verify

1. Zone A (radial rows [,8,91), has a total mass of > [733,400] lbs

2. Zone B (radial rows [4,5,6]), has a total mass of > [733,400] lbs

3. Zone C (radial rows [1,2,3]), has a total mass of > [733,400] lbs.

Insert B Verify the ice mass of each basket sampled in SR 3.6.15.2 is > 600 lbs.

TS Bases 3.6.15 First line of page B 3.6.15 revise bracketed value to [2,200,000]

Insert on page B 3.6.15 revise to "exist in the ice baskets, the ice to be appropriatel Insert D Page 2 of 4

Ice mass determination methodology Is designed to verify the total as-found (pre-maintenance) mass of lce in the Ice bed, and the appropriate distribution of that mass, using a random sampling of individual baskets. The random sample will indude at least 30 baskets from each of three defined Radial Zones (at least 90 baskets total). Radial Zone A consists of baskets located in rows 7, 8, and 9] (innermost rows adjacent to the Crane Wall), Radial Zone B consists of baskets located in rows [4, 5, and 6J (middle rows of the ice bed), and Radial Zone C consists of baskets located in rows [1, 2, and 3] (outermost rows adjacent to the Containment Vessel).

The Radial Zones chosen indude the row groupings nearest the inside and outside walls of the Ice bed and the middle rows of the ce bed. These groupings facilitate the statistical sampling plan by creating sub-populations of ice baskets that have similar mnean mass and sublimation characteristics.

Methodology for determining sample ice basket mass will be either by direct lifting or by alternative techniques. Any mnethod chosen by the Ucensee will indude procedural allowances for the accuracy of the method used. The number of sample baskets in any Radial Zone may be increased as necessary to verify the total mass of that Radial Zone.

In the event the mass of a selected basket in a sample population (initial or expanded) cannot be determined by any available means (e.g., due to surface ice accumulation or obstruction), a randomly selected representative alternate basket may be used to replace the original selection in that sample population. If employed, the representative altemate must meet the following criteria:

a.

Alternate selection must be from the same Bay-Zone (i.e., same Bay, same Radial Zone) as the original selection, and

b.

Altemate selection cannot be a repeated selection (original or alternate) in the current surveillance, and cannot have been used as an analyzed altemate selection in the three most recent surveillances.

The complete basis for the methodology used in establishing the 95% confidence level in the total ice bed mass is documented in Ref. 4.

The total ice nass and individual Radial Zone ice mass requirements defined in this surveillance, and the minimum ice mass per basket requirement defined by SR 3.6.15.3, are the minimum requirements for OPERABILITY. Additional ice mass beyond these surveillance requirements is maintained to address sublimation. This sublimation allowance is generally applied to baskets in each Radial Zone, as appropriate, at the beginning of an operating cycle to ensure sufficient ice is available at the end of the operating cyde for the ice condenser to perform its intended design function. As documented in Ref. 4, Licensee's maintenance practices actively manage individual ice basket mass above the required safety analysis mean for each Radial Zone.

Specifically, each basket is serviced to keep its ice mass above [1132] lbs for Radial Zone A, [1132] lbs for Radial Zone B, and [1132] lbs for Radial Zone C. If any basket is identified to be deficient with respect to these ice mass values, this condition is to be addressed in the Licensee's corrective action program. This alone is not considered a significant condition adverse to quality as long as the ice mass requirements of SR 3.6.15.2 and SR 3.6.15.3 remain satisfied.

Page 3 of 4

The Frequency of 18 months was based on ice storage tests, and the typical sublimation allowance maintained In the Ice mass over and above the minimum ice mass assumed in the safety analysis. Operating and maintenance experience has verified that, with the 18 month Frequency, the minimum mass and distribution requirements in the ice bed are maintained.

Insert E Verifying that each selected sample basket from SR 3.6.15.2 contains at least 600 lbs of ice in the as-found (pre-maintenance) condition ensures that a significant localized degraded mass condition is avoided.

This SR establishes a per basket limit to ensure any ice mass degradation is consistent with the initial conditions of the DBA by not significantly affecting the containment pressure response. Ref. 4 provides nsights through sensitivity runs that demonstrate that the containment peak pressure during a DBA is not significantly affected by the ice mass in a large localized region of baskets being degraded below the required safety analysis mean, when the Radial Zone and total ice mass requirements of SR 3.6.15.2 are satisfied. Any basket identified as containing less than 600 lbs of ice requires appropriately entering the TS remedial action for an inoperable ice bed due to the potential that it may represent a significant condition adverse to quality.

Page 4 of 4

0 NC UNITED STATES NUCLEARREGULATORY COMMISSION WASHINGTON, D.C. 205550001

• 1 ito May 6, 2003 Mr. R. S. Lytton Chair, Ice Condenser Utility Group Duke Power Company P. 0. Box 1006 Charlotte, NC 28201-1006

SUBJECT:

DRAFT SAFETY EVALUATION FOR ICE CONDENSER UTILITY GROUP TOPICAL REPORT NO. ICUG-001, REVISION 0: APPLICATION OF THE ACTIVE ICE MASS MANAGEMENT CONCEPT TO THE ICE CONDENSER ICE MASS TECHNICAL SPECIFICATION (TAC NO. MB3379)

Dear Mr. Lytton:

The Nuclear Regulatory Commission staff is continuing its review of the Ice Condenser Utility Group (ICUG) Topical Report No. ICUG-001, Revision 0, Application of the Active Ice Mass Management Concept to the Ice Condenser Ice Mass Technical Specification," submitted by the Duke Power Company (DPC) in a letter dated September 18, 2001, as supplemented by letters dated June 12, October 10, October 22 and November 26, 2002.

The enclosed Draft Safety Evaluation (SE) reflects the progress of the review conducted to date. There are several unresolved issues within the draft SE. We have planned with your staff to discuss these issues in a meeting in Rockville, Maryland in the near future. Therefore, to facilitate the resolution of issues in that meeting, we are providing the draft SE. The resolution of these issues may require an additional submittal of information and an updated revision of the Topical Report.

Should you have questions or comments, please contact Mr. Robert Martin of my staff at (301) 415-1493.

Sincerely, A. Nakoski, Chief, Section 1 P.roject Directorate II Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket Nos. 50-413, 50-414, 50-369, 50-370, 50-327, 50-328, 50-390, 50-315 and 50-316

Enclosure:

As stated cc w/encl: See next page

)

McGuire Nuclear Station Catawba Nuclear Station cc:

Ms. Lisa F. Vaughn Legal Department (ECIIX)

Duke Energy Corporation 422 South Church Street Charlotte, North Carolina 28201-1006 County Manager of Mecklenburg County 720 East Fourth Street Charlotte, North Carolina 28202 Mr. Michael T. Cash Regulatory Compliance Manager Duke Energy Corporation McGuire Nuclear Site 12700 Hagers Ferry Road Huntersville, North Carolina 28078 Anne Cottingham, Esquire Winston and Strawn 1400 L Street, NW.

Washington, DC 20005 Senior Resident Inspector c/o U. S. Nuclear Regulatory Commission 12700 Hagers Ferry Road Huntersville, North Carolina 28078 Mr. Peter R. Harden, IV VP-Customer Relations and Sales Westinghouse Electric Company 6000 Fairview Road 12th Floor Charlotte, North Carolina 28210 Mr. Richard M. Fry, Director Division of Radiation Protection North Carolina Department of Environment, Health, and Natural Resources 3825 Barrett Drive Raleigh, North Carolina 27609-7721 Ms. Karen E. Long Assistant Attomey General North Carolina Department of Justice P. O. Box 629 Raleigh, North Carolina 27602 Mr. C. Jeffrey Thomas Manager - Nuclear Regulatory Licensing Duke Energy Corporation 526 South Church Street Charlotte, North Carolina 28201-1006 NCEM REP Program Manager 4713 Mail Service Center Raleigh, NC 27699-4713 Mr. T. Richard Puryear Owners Group (NCEMC)

Duke Energy Corporation 4800 Concord Road York, South Carolina 29745 Dr. John M. Barry Mecklenburg County Department of Environmental Protection 700 N. Tryon Street Charlotte, North Carolina 28202

McGuire Nuclear Station Catawba Nuclear Station cc:

Mr. Gary Gilbert Regulatory Compliance Manager Duke Energy Corporation 4800 Concord Road York, South Carolina 29745 North Carolina Municipal Power Agency Number 1 1427 Meadowwood Boulevard P. O. Box 29513 Raleigh, North Carolina 27626-0513 County Manager of York County York County Courthouse York, South Carolina 29745 Piedmont Municipal Power Agency 121 Village Drive Greer, South Carolina 29651 Saluda River Electric P. O. Box 929 Laurens, South Carolina 29360 North Carolina Electric Membership Corporation P..0. Box 27306 Raleigh, North Carolina 27611 Senior Resident Inspector 4830 Concord Road York, South Carolina 29745 Mr. G. R. Peterson Site Vice President Catawba Nuclear Station Duke Energy Corporation 4800 Concord Road York, South Carolina 29745 Mr. Dhiaa Jamil Vice President, McGuire Site Duke Energy Corporation 12700 Hagers Ferry Road Huntersville, North Carolina 28078 Virgil R. Autry, Director Division of Radioactive Waste Management Bureau of Solid and Hazardous Waste Department of Health and Environmental Control 2600 Bull Street Columbia, South Carolina 29201

Mr. J. A. Scalice Tennessee Valley Authority cc:

Mr. Karl W. Singer, Senior Vice President Nuclear Operations Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. James E. Maddox, Acting Vice President Engineering & Technical Services Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. Richard T. Purcell Site Vice President Sequoyah Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Soddy Daisy, TN 37379 General Counsel Tennessee Valley Authority ET 11A 400 West Summit Hill Drive Knoxville, TN 37902 Mr. Robert J. Adney, General Manager Nuclear Assurance Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. Mark J. Burzynski, Manager Nuclear Licensing Tennessee Valley Authority 4X Blue Ridge 1101 Market Street Chattanooga, TN 37402-2801 SEQUOYAH NUCLEAR PLANT Mr. Pedro Salas, Manager Licensing and Industry Affairs Sequoyah Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Soddy Daisy, TN 37379 Mr. D. L. Koehl, Plant Manager Sequoyah Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Soddy Daisy, TN 37379 Senior Resident Inspector Sequoyah Nuclear Plant U.S. Nuclear Regulatory Commission 2600 Igou Ferry Road Soddy Daisy, TN 37379 Mr. Lawrence E. Nanney, Director Division of Radiological Health Dept. of Environment & Conservation Third Floor, L and C Annex 401 Church Street Nashville, TN 37243-1532 County Executive Hamilton County Courthouse Chattanooga, TN 37402-2801 Ms. Ann P. Harris 341 Swing Loop Road Rockwood, Tennessee 37854 Mr. J. A. Scalice Chief Nuclear Officer and Executive Vice President Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, Tennessee 37402-2801

Mr. J. A. Scalice Tennessee Valley Authority cc:

Mr. Karl W. Singer, Senior Vice President Nuclear Operations Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. James E. Maddox, Acting Vice President Engineering & Technical Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. William R. Lagergren Site Vice President Watts Bar Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Spring City, TN 37381 General Counsel Tennessee Valley Authority ET 11A 400 West Summit Hill Drive Knoxville, TN 37902 Mr. Robert J. Adney, General Manager Nuclear Assurance Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. Mark J. Burzynski, Manager Nuclear Licensing Tennessee Valley Authority 4X. Blue Ridge 1101 Market Street Chattanooga, TN 37402-2801 WATTS BAR NUCLEAR PLANT Mr. Paul L. Pace, Manager Licensing and Industry Affairs Watts Bar Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Spring City, TN 37381 Mr. Larry S. Bryant, Manager Watts Bar Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Spring City, TN 37381 Senior Resident Inspector Watts Bar Nuclear Plant U.S. Nuclear Regulatory Commission 1260 Nuclear Plant Road Spring City, TN 37381 Rhea County Executive 375 Church Street Suite 215 Dayton, TN 37321 County Executive Meigs County Courthouse Decatur, TN 37322 Mr. Lawrence E. Nanney, Director Division of Radiological Health Dept. of Environment & Conservation Third Floor, L and C Annex 401 Church Street Nashville, TN 37243-1532 Ms. Ann P. Harris 341 Swing Loop Road Rockwood, Tennessee 37854 Mr. J. A. Scalice Chief Nuclear Officer and Executive Vice President Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, Tennessee 37402-2801

Donald C. Cook Nuclear Plant, Units 1 and 2 cc:

Regional Administrator, Region IlIl U.S. Nuclear Regulatory Commission

.801 Warrenville Road Usle, IL 60532-4351 Attorney General Department of Attorney General 525 West Ottawa Street Lansing, Ml 48913 Township Supervisor Lake Township Hall P.O. Box 818 Bridgman, Ml 49106 U.S. Nuclear Regulatory Commission Resident Inspector's Office 7700 Red Arrow Highway Stevensville, Ml 49127 David W. Jenkins, Esquire Indiana Michigan Power Company One Cook Place Bridgman, Ml 49106 Mayor, City of Bridgman P.O. Box 366 Bridgman, Ml 49106 Special Assistant to the Governor Room 1 - State Capitol Lansing, Ml 48909 Drinking Water and Radiological Project'Division Michigan Department of.

Environmental Quality 3423 N. Martin Luther King Jr. Blvd.

P. 0. Box 30630, CPH Mailroom Lansing, Ml 48909-8130 Scot A. Greenlee Director, Nuclear Technical Services Indiana Michigan Power Company Nuclear Generation Group 500 Circle Drive Buchanan, Ml 49107 David A. Lochbaum Union of Concerned Scientists 1616 P Street NW, Suite 310 Washington, DC 20036-1495 Michael J. Finissi Plant Manager Indiana Michigan Power Company Nuclear Generation Group One Cook Place Bridgman, Ml 49106 Joseph E. Pollock Site Vice President Indiana Michigan Power Company Nuclear Generation Group One Cook Place Bridgman, Ml 49106

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON. O.C. 20555-001 DRAFT SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATING TO TOPICAL REPORT ICUG-001, REVISION 0 APPLICATION OF THE ACTIVE ICE MASS MANAGEMENT CONCEPT TO CONDENSER ICE MASS TECHNICAL SPECIFICATIONS/

ICE CONDENSER UTILITY9UP /

y.-

1.0 INTRODUCTION

zopp?,

ASeF

`

By letter dated September 18, 2001, (Reference 1), ag supplented by letters d October 10, October 22 and November 26, 2002 (Ref e ini22 4, and 5), the Condenser Utility Group (ICUG), representing the Cat

,pi ire Nuclear Sequoyah and Watts Bar Nuclear Plants and the Dold C.... k:N..,lar Plant, Nuclear Regulatory Commission (NRC) staff reviewfe an d approv.picaI Re ICUG-001, Revision 0, aApplication of the Actiyloe Mass Managentoncept Condenser Ice Mass Technical Specificatio__

ICE A'tedJune 12, Ice Stations, the submitted for port:

to the Ice I

The topical report describes the basis revision to the generic ice condenserc ICC ice bed. This issue is also ad (TSTF) traveler number 429, Re n

proposed revisions to the TS S,eillai ICC ice baskets.

A,,

ed ir Dgupp rt an industry-proposed CC) 1T7chical Specification (TS) for the by tM Technical Specification Task Force ay,7, 2002, (reference 6) that describes

,f(SR) for determining the mass of the The ice within the1 a design bc In NUREG-Condition f, of la maint provic is adg ain,Ifiecontainr?

d The SR for quate by taking lition, determinir of the ice bed is W, the ICUG Dri

t!milIion poi1nds of ice stored in 1,944 twelve foot long baskets yp,>,s,

-o provide a large heat sink to absorb heat in the event of DB4 f+,,f>nqent. The standard TS for the ICC Ice bed is included rd Te Tg;$ecifications for Westinghouse Plants.' The Umiting

.4) for tice bed requires that a sufficient amount of stored ice to

'ar>emperature and pressure within the DBA design bases limits be i,,,,,&ghing program is intended to verify that the total weight of ice iwe of the ice baskets to determine the weight of the entire ice bed.

e weight of an appropriate sample of baskets ensures that no local cient in ice. Based on the operating experience of ice condenser J several changes to the current ice mass TS.

The' aff's review of the topical report and TSTF-429 included the following areas:

(1) Active Ice Mass Management (AIMM) and total ice mass requirement concepts, (2) the minimum ice mass requirement for individual ice baskets, (3) methodologies for determining ice basket mass to the degree supported by the generic topical report, (4) the concept of sampling from three radial zones in the ice bed and altemate basket sampling, and (5) the ice mass statistical sampling plan.

2.1 Active Ice Mass Management and Total Ice Mass Requirement 2.1.1 Technical Information in the Topical Report and TSTF-429 AIMM uses active monitoring of varying sublimation rates to support the proce the ice baskets to restore ice bed mass. The ice sublimation rates are',ifferel areas of the ice condenser. The plant-specfic ice basket subliti A a from operating experience and is trended using softwareg

as I....A....r MANAGEMENT program). Table A-i of the topical reporesents a#e ft sublimation data from Catawba, McGuire, Sequoyah, F,. Watts Bag,alar 1

compiled and normalized to reflect a typical ice conde ser planj/

s'of replenishing in different be obtained CE condenser Wposite histod6af The current TS requires an uas-leftu (post-maintenanc distribution. With this approach, an operational cycle outage the ice baskets are replenished to meet the SI provided for the following operational cycle. This reqt (and weighing error) allowance be added to the ice-n the SR. In the current standard TS, the total "a t

the coming operational cycle. (Note: The b e ed specific requirements.)

3s th ice of the total ifc emass and 3d and during the following

,t,sufficient ice will be ssurnd uniform sublimation 9BIoi the DA analysis to reet f2.~71

[,:

,O]lbs is required for b&Sdusted to reflect plant-Ss of

.ould The proposed revision to the stan maintenance) surveillance of the I SR 3.6.15.2 of the proposed TS minimum requirement for ice bef cycle and it Vgrifies that the4so cycle's reqrreents.

1 with pro s

perat ind ic founi rnot ir fS. as s-efftforth in iSTF429, uses an as-found" (pre-ss. Tletotal ice,imass of 2,346,408] lbs is specified in thejue use f-iithe DBA analysis. This value is the AilM3 The SBIO'conducted at the end of an operational csEe end of a cycle was adequate for that d~pprGac, the sublimation allowance and mass cluded in the TS but will be maintained in accordance s the ice baskets to be serviced under plant idual basket sublimation rates. The practice of sublimation experience, to maintain the ice bed is the managing in foundations 2.1.2 Evaluation Tt -"staff reviewed the as posed AIMM concept described in the topical report. This concept coup0es the plant-spe,Ac ice maintenance procedures to the TS SR for the total ice mass emuirement. HoweVre' the topical report did not describe the procedures in sufficient detail. In ffiuests for addlitnRal information (RAI) Nos. 1 and 2, the staff requested that the ICUG fcalvid

~c~py~A typical plant-specific procedures to support an improved understanding of hGw the Ic maintenance procedures (i.e., AIMM methodology) can be used with the TS surv'iulai'ce to establish the total ice mass requirement. The ICUG responded that the plant-specific procedures were not available. They would be developed after the approval of the topical report and TSTF. Therefore, the NRC staff will consider the need for submittal of these procedures during plant-specific reviews of proposed changes to plant TS. However, in response to the specific questions identified in the RAls, the ICUG provided additional information about the plant-specific ice maintenance procedures.

The ICUG stated that the plant-specific Ice bed maintenance procedures monitor sublimation rates and ice basket masses from operating cycle to operating cycle. The monitoring of the ice mass depletion rates is periodic, occurring each time the plants perform maintenance-related ice basket mass determination (weighing) procedures. Because the ice mass depletion rates tend to be linear and consistent with sufficient historical data, the mass of the inflh any basket can be predicted. The ICUG stated that if an anomaly occurred, it coufldbe f2iuid from either control room indicators, ice bed temperature surveillance r'quireme,p,,

A iiquent procedurally-mandated online ice condenser inspections anor

_d..,be addressedy corrective action in accordance with the licensee's progg or meet ments ofv Title 10 of the Code of Federal Regulations (10 CFR) P-.-' t 50, Appe1'1ix (R ftece 7)Af a condition should develop during operation such that itu, Id restrflr' the T gt d,

the TS action statements require that the plant be bro,,> tq.0Sfe mode of op,t"'n response to RAI No. 1, ICUG stated that under the prpe emass SRs, the fomial documentation of the existing ice mass maintenance pr e

ld be part of the plant-specific TS implementation. These practices satisfy tb

-maintenance) SRs and assure compliance with the LCO. The sublimation a&i error aiw,,

and associated methodology, will be formally documented at eachv pant. Thess are maintained pursuant to the requirements of the Commiss nfos in 1 art 50, Appendix B, and 10 CFR 50.59.

/

\\

The proposed total ice mass requirem found" total ice mass, and (2) the plan sublimation and weighing errors. Xe amount of total ice in the ice co9dfnso sublimation requirements durinpoe procedures are maintainedia-orda ThereforRe,,&>,RC sta9~b All\\J require'T F-429 oZpl

)mbi

,elem el~t M

iEN e TS SR to specify the as-e maintenae procedures to manage n of th$' two elements ensures a sufficient ing t during DBAs and for meeting

.,Als,t as noted above, the plant-specific UI Part 50, Appendix B, and 10 CFR 50.59.

and its application for the total ice mass atiI nc By letter dat, proposed T' that the val UFSAFISect The vbiof lice,>ge will artv--is Th r2 tion 14.3:W1

([2,346,4C specify th ie NRC st; Sto be ac 6,

n'-OjV(%ence 5) the ICUG revised the bracketed value in the e ma i2,346,408] lbs to [2,200,000] lbs. The ICUG clarified 4lbs corresponds to the "as-found" total ice mass in D. C. Cook

,,,,, upper bound value representative of all ice condenser plants.

te'sniit correspond to any specific ice condenser plant. Each Te:of this bracketed parameter based on their plant-specific safety ids the change of the bracketed value of 12,200,000 lbs in the sed Tc Requirement for Individual Ice Baskets Information in the Topical Report and TSTF-429 The topical report, Revision 0, states that the oginal intent of the ice mass requirement for individual ice baskets was to prevent localized gross degradation of the ice bed from creating a "bum-through" scenario' during the blowdown phase of a large-break loss-of-coolant accident (LOCA). The ICUG established the requirement for the minimum ice mass for Individual ice baskets to be the amount of ice required during the blowdown phase of a LOCA. The topical report refers to this minimum ice mass as the "blowdown ice mass." If a bum-through scenario occurred, it could cause a chimney effect In ice condenser bays, and provide a path for steam to bypass the ice bed and get into the upper compartment without being condensed.

The methodology used to implement the proposed TS SR 3.6.15.3 re(

the minimum ice mass for individual ice baskets by ensunng that the sampled in SR 3.6.15.2 is no less than [400] lbs. The bract),gted paw values to be specified for individual plants. In response beNRC (Reference 2), the ICUG provided the plant-specific minf(mum blowdcw lbs/basket for McGuire and Catawba, 325 lbs/basket f&cS'1$equoya>,1; Bar, and 334 lbs/basket for D.C. Cook.

ires i Ases to verify sf each basket

• ws plant-specific lo. 4 be 2.2.2 Staff Evaluation The current licensing bases (CLB) fc condenser plants is based on the as A bum-through scenario in the ice b a LOCA would invalidate the assumg analysis and challenge the containm the basis for compliance with Gener GDC 50, Containment Design Basis 3.6.15.2.a, by requiring the sampled lbs limit is the 'as-left' average ice,.

bum-through during both the blo+f basket contains less than [1400J lbs.

20 additionlbaskets frorWje, me Becau^

e,p-ose lo:

~~~~~~~~~~f or the long-tern co im iegrity analysis for ice sumption of a uriform fIdWdjstribbpUon through the ice bed.

3d during both ebowdow,,sblowdown phases of ption, and4 A-1d ae the reAsoti,gf a LOCA containment lent dei:

'Te cont"" nment design pressure is

~l D~gn Crtedia (GQ 1~~otiment Design" and s.

"SR~~~~neminS

.i'e basketNto have n [1400] lbs of ice. The [1400]

xa's per tgsket, whi,iiis sufficient to prevent ice Wn an>gist-blowwn phases of a LOCA. If a single the curwnt TS Bses for SR 3.6.15.2 specifies weighing bay there is no local ice deficiency.

Ndo in the topical report addresses the ice wdown ase only, the NRC staff found that this minimum ttjce bum-through during the post-blowdown phase of a

,t4bution as required by the CLB.

In RAl demor oressu isit>te that ne; I&P. In its respol I would result ir on the results

1) computer cog tribution factof'

,istSed th the ICUG provide a quantitative analysis, or test data to 3t,,,b!,

down ice bum-through had no impact on the peak containment rs nnf1rence 2, the ICUG stated that the post-blowdown ice bum-n &decrease in the peak containment pressure. The statement was f analyss, using the Westinghouse Long Term Ice Condenser le to show that for a non-uniform flow distribution with a flow gf 1.36, the peak containment pressure was lower than the pressure with C staff reviewed the analysis and found that the single value um-through' is a term used by the ICUG to refer to melting of ice in the baskets sufficient to create a large local steam flow channel within the ice baskets. "Melt-through' could be a more accurate description of the actual physical process.

2 An example of the current TS is provided in Appendix A of reference 1.

maldistribution factor (1.36) did not represent the post-blowdown ice bum-through phenomena associated with the condition of having an ice mass as low as the blowdown ice mass.

Specifically, the staff concem was that once ice bum-through started at the end of blowdown (approximately 30 seconds), it could grow quickly and change the flow pattem significantly.

After 6000 seconds of post-blowdown ice bum-through, there was no reason to believe that the maldistribution could be maintained as a constant or be limited to a value of 1.36. It appeared that the LOTIC analysis only provided qualitative information about the impact of a.specific non-uniform flow distribution, and it could not be used to address the severe ice bum'-through that might result from having a blowdown ice mass of [400] Ibs per basket*e NRC staff determined that ICUG's LOTIC analysis was not adequate justify

. own ice mass methodology, and communicated its concem to the ICU e

October 1, 2002.

A v

In its response dated October 22, 2002. the ICUG pei computer code GOTHIC with the McGuire containmer pressure of 15 psig. The results of the analysis are sl nsitivity ah jire containi ice mass lbs/basket peak containmen pressure P, psig

.1.^..

increae from bas p"argin margin (p1, from reduction, I4p$ig AP/ 1.56, 1 r 1.56 O

t I

Base Case 973 (all baskets)

Case 1 600 (75 baskets)

Case 2 400 (75 baskets)

I-Case 3 400 (225 I 173 i1379/

(-

-F 1.27 19 1.50 3.8 1.21 22 Blowndow Ice Mass 288 I -

unanalyzed For a rang&i results show trend is conti pressuresAi.

plant-s

...k the aiiiounts of t.

above m

i blowdo%

analyzed table, the iificantly r Id not su1A as70.s~Q, and 400 bs/basket) in a group of ice baskets, the k conressunt~pressures increase, with decreased ice mass. This s>,previoW$,

'ponse to RAI No. 5, which would predict the peak iiXe Base &ase (13.44 psig). Further, it should be noted that the s

for McGuire is 288 lbs/basket, which is much less than any of 1 gwqTd result in a more severe impact. As shown in the last column ar1n reduction resulting from a blowdown ice mass of 288 lbs/basket e than 22 percent. Therefore, the NRC staff found that the GOTHIC t the ICUG's methodology for the minimum blowdown ice mass.

be sigr is coul The NR,C:staff'dlocised its concem with the ICUG in a telephone conference, on November 1t~3,ang

~na**iie~

g on November 14, 2002. During the meeting, the ICUG stated that the McGub.

conainment response is not significantly sensitive to ice mass maldistribution and that for the above ice mass sensitivity cases, there are no significant changes in the containment pressure response. The NRC staff disagreed with the ICUG. The base case of 973 lbs per basket corresponds to the "safety analysis mean' for individual baskets in the McGuire ice bed.

Based on the sensitivity analysis, for a small ice reduction (from 973 lbs to 600 lbs per basket),

the amount of localized ice bum-through would have a relatively insignificant impact on the peak containment pressure. For the intermediate cases, Cases 2 and 3, the pressure increases are 0.29 psi and 0.35 psi, respectively, corresponding to a margin reduction of 19 percent and 22 percent, respectively. For a severe reduction from the safety analysis mean to the blowdown ice mass (from 973 lbs to 288 lbs per basket for McGuire), the amount of localized ice bum-through could have a significant impact on the peak containment pressure, and could challenge the containment pressure design limit. Furthermore, it shoulfbe noted that the design margins are plant-specific values. The other ice condepser plan, nay have lower containment design pressures and smaller design margins cor,ed t,^cGuire. These less favorable design parameters for other plants would reslt in mo, xnificant impacts on the peak containment pressure.

A111 2.2.3 Revised Ice Mass Requirement for Individual Ice In its response dated November 26, 2002 (reference 5) methodology and a revision to the topical report and tc specifying the minimum ice mass per basket. In the res to revise the topical report to require that ice basket ma usafety analysis mean" under their AIMM practices. Ac the TSTF will be revised to state that the licensee'a.pi individual ice basket mass above the required.

,dftAr Specifically, each basket is maintained to WE s

zone. Nonconforming conditions will bedessed The bracketed value of [ 132] lbs is a piat-spec ifiex, the D.C. Cook UFSAR, and is an upQ ':bound.t&othe sket

ordingl ntenan proposed a,1,v,se to resolve the iss' of odology, the ICUG committed

,aped at a level above the tIi ss for SR 3.6.15.2 of

,r~ok~esactively manage

!anl ss for each radial zone.

e [fl3 2] lbs for each radial

~ corrective action program.

Me safety analysis mean from

,nser plants.

In the Reference 5 revision to T 9, S13.6.1 5.2,4Ahe minimum ice mass per basket limit was changed to 600 lbs per baSket The

-rviousy yaue, as noted in the Reference 2 response to RAI No. 1>was [400 I

w zag for plant specific values to be specified.

It is notedfi-the revis,,,,f 600 l o

osed without a plant-specific variation (i.e.,

no bra d fore 00 lbs sintended to be applicable to all ICC plants.

The NRC stathe revj,,^,n,,,od and detemined that the safety analysis mean is the amount of to prevent local ice bum-through during a LOCA. Ac eg t

Ice ss of individual baskets to the safety analysis mean will prevent J,,1 ice bun could result from the blowdown and post-blowdown phases.

Allow, icensees to n ividual ice baskets is consistent with the AIMM concept, disc ed in Section 2.1 abiwe, where licensees are allowed to manage ice sublimation. The prp sed TS limit of 60bs of ice mass per basket was evaluated in Section 2.2.2. Case 1 (eOOib) shows that thmount of localized ice bum-through has a relatively insignificant impact OiP~6tainment presure. Because the impact may vary from plant to plant, combining the TS lf bs) wictive management (plant-specific safety analysis mean) provides

_easonable I~tirance that the impact of local ice bum-through will be either insignificant or no-existant.'The revised methodology for the requirement of ice mass per basket has two elent 1 ) the plant-specific active ice management to "safety analysis mean" for individual baskets, and (2) a TS surveillance requirement of 600 lbs per basket. The NRC staff finds that the combination of these two elements, as specified in the revised TSTF-429, is acceptable.

The discussion of these two elements should also be included in the topical report.

However, the NRC staff noted some inconsistencies in the revised topical report. For example, on page 0-3, Summary of Significant Aspects:"... to manage the ice mass in each basket above the required technical specification mean,"... should read as "safety analysis mean." On page 1-1, Design Basis," the discussion in this section was to establish the basis for the "minimum blowdown ice mass" alone, which is inconsistent with the revised TSTF-429, Revision 1. It should.be noted that the revised methodology Is based on the combination. of both an active ice management goal and a TS limit. The ICUG should ensure that the discussion of the revised methodology in the topical report treats both elements1hfroughout the report consistently. The ICUG should incorporate the above comment.Thto RBvision 1 of the topical report.

At W

2.3 ce Basket Mass Determination Methodoloav 2.3.1 Technical Information in the Topical Report As the ICUG notes in Section 11 of the topical report, hi mass has been through manual lifting and weighing of discussed below, have been used to predict the numtf replenishment during outages to meet the TS SR, the to meet the SR has been by manual lifting and wei9htn basket weight is typically determined by lifting-tIlŽS or load cell. The topical report (Section ) s t t.ta determination of ice mass, and is the pref&red metc t determinati6of' Ice basket

\\though other methods,

..ts that would require

.i.>ation of ice basket mass -

~t~An individual ice gand an attached scale bides the most accurate ot ice I w

aitha However, some baskets may becoi lattice framework, thus preventingA has proposed several alternate oin baskets. These methods inclu rmeasurements of basket n

MANAGEX sofDOW 'nam they were' vy ick, as.Aresult o,ets freezing to the supporting rom,bMing physrlly lifted and weighed. The ICUG te Sination m $ods to address the issue of stuck mti.9ng theasket weight based on previous rtid~rht data using the ICEMAN (ICE

~ estinatig basket weight based on visual br m>ehiods were mentioned in the topical report but

and, 4I othe The licensee and can be ana prey s ice basKt signifi nt amount of a obtieed by using less be6aise the effect of L IsPeiction method use it nt of mass mis. d ifflICEMA tware program that trends ice basket mass histories e.uture g1, asket mass based on valid ndividual sublimation rates ft m ata. This alterate mass determination technique requires a ocr0

'Wce mass data to generate projections. The data that were

~ccLI5t methods are generally not used in ICEMAN projections, a..er measurement error will be compounded over time. Visual

a camera inspection over the length of the ice basket to estimate the Ig from the column in the form of linear gaps, shaped voids, and annular e basket mesh. The total amount of missing mass is subtracted from of a full basket to obtain an estimate of the mass of that basket.

Tabfe -of the topical report, "Mass Determination Method Errors (Reference Only)," shows a comparison of the relative accuracy for the manual lifting, CEMAN projections, and visual inspection methods. The report states that data in the table is for illustrative purposes and that actual plant data will vary from the values in the table. The table listed systematic bias (mean difference from manual lifting measurement), standard deviation, and assumed method random error. The standard deviations and assumed method random errors for manual lifting, ICEMAN projection, and visual inspection are (15 lbs and t 15 lbs), (69 lbs and + 40 lbs), and (177 bs and : 300 Ibs), respectively. The larger errors involved with the visual inspection method may necessitate larger (i.e., expanded) statistical samples in order to meet plant specific licensee maintenance objectives. The report states that as Ice condenser plants accumulate more operating data into their individual ICEMAN and visual estimation database, the mean difference and standard deviation will decrease, and the resultant projection will become more precise. The random errors associated with different methods (Chapter II of th"'pical report) has to be incorporated with the statistical analysis (Chapter 1II of the t;Ical &r) to obtain the 95 percent confidence level specified in the proposed TS.

• I,For any of the altemate mass determination methods, personnel to perform the method will be addressed on.

the determination of ice basket mass (e.g., equipments error and systematic bias) are maintained in plant-spe 2.3.2 Staff Evaluation on of traini s, treatm ures.

lent Table 2-1 of the topical report show weight (measured by lifting) by 13 It ICEMAN. Because underestimates acceptable. In RAI No. 8, the NRC radial rows, since different radial roi standard deviations. In the respons and standard deviation between ICE analysis, the ICUG concluded tha remains conservative over all th conservative in Rows 2-6, becafe mass. The4 mean differenig' respect, k.jhe s that ICEMAN, dn he av 116e, ri-i-restimates the true bs. This was statisically obtaid 9,470 projections by are consert Ie weighin fvellance, they are staff ask n

.or0fined ev-drf analysis in terms of vs typ ly havAir m

and, perhaps, different

e (rfedrence2 th.

he U

nalyzed the mean difference EMAN and ual liftt-determined by rows. Based on the hemean Wiflerence lRween ICEMAN and manual lifting dial row the iced. The mean difference is less in thesews t EMAN prediction is closer to the actual er torA/I n ment and crane wall (Rows 1 and 9, on ev rows shows a similar distribution; i.e., the in the Xmddle rows of the ice bed (Rows 2-6) because Ibetter, and the standard deviation increases as the rows diiL'~n crane wall.

taln uai1 ICEMAN move ou In RAI No

.jsskdl he ICUG to explain why the visual inspection method, that has a radom error Ob a viable option. In the response, the ICUG explained that the assum§d random erro s is a general value based on little data. Additional use of this meU. d may allow the e "be reduced. It is the intent of licensees to optimize the mass def rination process fir ice baskets, requirng that the standard deviations be adjusted for o~W1 obtained data.e ICUG indicated in reference 2 that since the proposed TS required qnfy~the minimum ldown ice mass (an extremely low limit) for an individual ice basket mass o

w.

th lower -... racy of the visual inspection method would not be a significant concem. It should behote..hat the NRC staff reviewed the methodology of minimum blowdown ice mass" in Sioru2.2n2 and found that it is not acceptable. Therefore, when using the visual inspection method, the ICUG should rely on reducing the measurement error rather than rely on a low limit of blowdown ice mass" for weighing individual ice baskets. Because the larger error involved with the visual inspection may necessitate larger statistical samples in order to meet the mass requirement, the process will encourage the improvement in error reduction.

The ICUG addresses industry challenges in its Overview section of the topical report, noting the maintenance challenges and introducing changes to the TS to respond to those challenges. In this instance the NRC staff is pdncipally concerned with ensuring that revised SRs will continue to provide adequate assurance of a sufficient mass of ice in the ICC to meet design basis safety analysis requirements. In this regard, the NRC staff considers that the most significant aspect of the overall ICUG topical report is.that the previous requirement to determine ice mass by weighing ice baskets would now be replaced by an SR that would allow deterrpination by any combination of three methods: (a) weighing baskets, (b) estimating weights byEMAN, or (c) estimating weights by visual inspection.

i The ICUG topical report has described the methods in c illustrative of the industry as a whole and has indicated contained in plant specific procedures. Therefore, the/

regarding implementation in response to plant-spefi direct weighing of baskets by scale or load cell is the C thus, will require the least additional information. ICE1N utility for maintenance purposes. The visual inspection I will require proportionately more inforrnation to justify t the methods to be applied on a plant-specific basis, (e categories of informiation:

rmiation that is ibnethod are:§:

C stati nse ai hdment p1fc"Iions'the of the thre elho~sand,

,n used extensive1y by one he least mature method and i

R,cific basis. For each of

uire the following NRLC a)

A discussion of the accu physical devices used ai justification for the stand be used for specific p dealing with the fo lLd'in thIhthod in terms of the ationri. A plant-specific

Wned method random error to provided. Discuss plans for devi; i)

At preser Uhere is fpAlmit oaifiW many times the two estimation mettdds ay be u azd zely to estimate the weight of a given The pro-ose&TS do not require the weighing of any baskets. Table A-1 of the to'fT St, indicates that estimation techniques will be used for

.ov0r 80 petit 4

lthe baskets in row 9 and over 70 percent of the t

Esk~ts in ro

, for example. Critera will be requested for the a-fpfrtion°f plant-specific mass determination to be performed by each iii)

The information supporting the bias and uncertainty values for the 2uinimum basket weight of 600 lbs criteron will be reviewed on a

,pant-specific basis for each license amendment application referencing the topical report.

b)

Prvide correlations and data to demonstrate the adequacy of estimation methods in predicting ice weight.

c)

Describe the processes that will ensure that once the adequacy of an estimation method is determined, it vill continue to be maintained.

d)

A discussion of the training and qualifications of the personnel that will perform the inspections or estimations.

e)

Identify any areas where the plant-specific application differs from the ICUG topical report.

f)

Provide a sample calculation showing how individual ice basket v measured and estimated, will be processed to determine complia limit values.

/

/

g)

Enclosure two to the November 26, 2002, ee(refr following:

If any basket is identified to be cient wih respect zone safety analysis mean] vald i tion is to b the Ucensee's corrective action This alone is nc significant condition adverse to q g

as the ice r requirements of SR 3.6.15.2 andi R2 5

ain satis In at least one licensee's Quality %qrnce Prog tion the corrective action program is-'......d.th co""it-kt3s that ai quality. Please discuss the c pes ses a.nicriteria in Assurance Program that wil. apply t issue in the corrective action prograf the cotiois idered to be quality.

/

2.4 Radial Zones in the Ice Bed1r;'ltemat Basket pmoling ht data, both with the TS s the nass sfied.

in a

(reference 9),

re adverse to the Quality e licensee's adverse to 2.4.1 T Infom Topi TSTF-429 A top-d(

of 1944 containr an 24 iwn in"ure A-1 of the topical report. The ice bed consists

,,arranged in approximately a 300 degree arc inside the 1*,"ip a 9 x 9 row-column arrangement.

Three ra next to

3. For,4i reasM,. able stanc totat mass of tha nhVnge from ti s'M.ipe will inclu ft.1 I h i r

~iwmUneM as follows: Zone A contains Rows 7, 8, and 9 (innermost rows wai)

Zonta 1_ontains Rows 4, 5, and 6, and Zone C contains Rows 1, 2, and purpooft.

zone has a similar expected as-found mean mass and a lard deXatiLtl. Taking random samples in each radial zone to estimate the t zone be [782,1361 lbs, as described in the topical report and TSTF-429, is ie curret TS for taking a limited azimuthal row-group sampling. The random le a least 30 baskets from each of these defined radial zones. The value of

?,third of the total ice mass in the ice bed. By letter, dated November 26, revised the value to [733,400] lbs as a result of a change of the bracketed ice mass (see Section 2.1.2 for evaluation)

In case of a physical obstruction or surface ice accumulation, an altemate sample basket from the vicinity of the initial sample will need to be selected. The altemate selection criteria have been designed using the radial zone concept, in which baskets in the same radial zone generally have similar mass. Altemate selections are representative of initial selections as long

- 1 1 -

as they have the same probability of being selected as an initial selection and can be expected to have similar characteristics as an nitial selection. The representative altemate must be from the same bay and same radial zone as the original selection. In addition, the use of altemate selections is restricted to preventing repeated use of the same altemate basket from affecting statistical confidence.

2.4.2 Staff Evaluation In reviewing Table 1-1 and Figure 1-2 of the topical report, the staff r differences in sublimation rates appeared among Rows 7, 8,9 andp exist in Row 9 than in Rows 7 or 8. In RAI No. 3, the NROsff asl differences and the frozen baskets would affect the accOdray of the using the radial zone concept.

ozen ice baskets explain how the In the response, the ICUG explained that the probabilof nee for the sample analysis is based on a blind, random s'strc the ice bed. Therefore, regardless of the sublimation ra15s;eac1-the same probability of being initially selected as any o

'ie grouping concept considers that baskets in the same adial operating lives" to approximately the same mean.m..ass. Becaus differences between rows, baskets in Radial

.Zo...n..

ctively limit such that every basket in the zone inh af-n.I" gen of the operating cycle. This is done by did ent rep has the effect of covering the mean bas et mass fa g&.'i're Row 9 are characteristically the mostli>ly to b ozen an,:have baskets in other rows, the beginninio-&cycle ass of stofd ice i than in Row 7 or Row 8. Therefd,Mt is lik that an at rnate se basket from Row 7 or Row 8 wOQd contai samor conserv; that of a RQW 9 basket in t.Xsound c basket being lected ategy that includ6&ai rows of basket in the radial zone has IiAhe zone. The radial zone g,il!4imate through their

.,of Mtwoted sublimation n~rrNied to the design basis ler,Jtysimilar mass at the end tquencies, a process which ecause the baskets in higher sublimation than n Row 9 is typically higher election of another sample atively less, stored ice than Altemat that the ol the surveill random sa zone as th, basketpA This rc

Bay, ne.

vtheiloe'asket as statistical replacement would typically indicate ianb~t~u~ied.nd its mass cannot be determined for the purpose of emai~e~eted-la:riteria were developed on the need to preserve the Lareas.

gtf6nate selection is limited not only to the same radial

.n, but aiso to the same bay. It prohibits the repeat use of an Ice I~sal altemate in any of the previous three most recent surveillances.

~ihthejotential of multiple statistical sample selections from a single si>ehat the plants have access to as many baskets as possible for

s. the combination of this altemate selection criteria and active ed ensures a 95 percent confidence level in the total mass of ice in term em(

dial; ltion, coupl ultimately ination of r ent of the ic zone.

UG'sclarification resolved the staff's concem that was identified in the RAI.

e-staff finds the proposed radial zone concept and altemate basket sampling acceptable.

• mr 2.5 Ice Mass Statistical Sampling Plan The surveillance to determnine the mass of ice in the ice bed consists of three activities: (a) the random selection of the sample group of 30 or more ice baskets for each radial zone, (b) selection of the mass determination method, whether by direct weighing or estimation, and (c) for weighing attempts that encounter stuck baskets either selection of an altemate basket or use of an estimation technique to determine the weight.

A.,

The ice mass statistical sampling plan is discussed in Chapter III of stated in the topical report, the sampling plan calls for a stga ificatioi zones, where Zone A comprises the first three rows next crar three middle rows of the ice bed, and Zone C includes 8hhree oul containment wall. A random sample of at least 30 baskets from eat for a total of at least 90 baskets for the entire ice bedTe distinct sampling is that it minimizes the risk that the sample Vif.hntam a d minority group. The selection of the sample size (at les.er zo baskets) is adequately explained in Chapter III of the top p

NRC staff. The sampling plan is acceptable to the st Weight measurements of each basket in the sam.ea.r e correcte using such measurements in any statistical caW-6jNs. MeasureT in two forms (Equation 3.1 and Equation 3 nr ort), a conservative. Licensees will be request

.. iden4 and to describe the implementation of Jttmethos) oe

,port. As lation by radial B includes the t1.o the tadvanta@ the stried disproportion~e number of a ne for a total t6Sa'least 90 and is acceptable to the

.rs-ematic bias before

~ent~uncertainties are given fwhich the latter is more jtilize one or both methods cific basis.

The ICUG has recognized that uncertainties, this must be acc mean. The topical report's met methodology.fldescribed in Ct.

the repoe lTt&NRC s

methodi Rfrnce 8~rfi t d for i Tforac(

8.3.1. 4 iewed t itl to be IK%tare used that have relatively large ftalculation called the error of the is is derived from the statistical 8 and is described by equation 3.2 of of equation 3.2 for consistency with the The main deviation I 95 percen main statF are acd,p erce

,t a

.e mass determination are the average and the standard iwer' fconfidence limit (LCL) is constructed. Thus we are Ave ht is not below the calculated LCL The calculations of the population correction for the standard deviation) and the LCL able to the II tion to the criterion of 1uir^ment for an acceptable estimate of the total ice mass, a minimum

.tis is set for each of the baskets selected for the sample. The measured tinting for bias and measurement uncertainty, must not fall short of the erion. The information supporting these bias and uncertainty values will be

-specific basis for each license amendment application referencing the 3.0 Conclusion The NRC staff has reviewed Topical Report ICUG-1, Revision 0, Application of the Active Ice Mass Management Concept to the Ice Condenser Ice Mass Technical Specification." The NRC staff finds, based on the evaluation provide above, that the following concepts and methodology are acceptable: the AIMM concept and total ice mass requirement, the radial zone concept for sampling and altemate basket selection and the ice mass statistical sampling plan. The ice mass determination methods will be evaluated on a plant-specific basis. However, the NRC staff found that specifying the minimum individual basket Ice mass to be ablowdown ice mass" and the bracketed value of 400 lbs is not acceptable (see evaluation in Section 2.2.2). The NRC staff finds the revised ice mass requirement for individual Ice baskets of 600 bs, s discussed in Section 2.2.3, to be acceptable. However, the NRC staff noted some I consisencibes between the revised TSTF-429 and the revised topical report and provided cor 'entsSection 2.2.3 of this SER. The ICUG should incorporate the above comments into Re IMof the topical report.

4.0 REFERENCES

1.

Letter from R. S. Lytton, Chair, Ice Condenser US Nuclear Regulatory Commission, Ice Cond' ICUG-001: Application of the Active Ice Mass M<

Condenser Ice Mass Technical Specification.",(

2.

Letter from R. S. Lytton, Chair, Ice Condense,U US Nuclear Regulatory Commission, "RCs Group Topical Report No. ICUG-00)e Management Concept to the Ice ndense,i TSTF-429, Rev. 0 (TAC Nos. t0;3369 arMB3 p, Duke Po wi-y, to v Group Topica' Report No.

kt Concept to the Ice j§369), September 18,2001.

"D e Power Company, to

~i'6jb t Ice Condenser Utility zf theActive ce Mass hiical Specification," and

.ie 12, 2002.

ility Gr

3.

Letter from R. S. Lytton, (

US Nuclear Regulatory 0 Condenser Utility Groupf Ice Mass Managem

. )t

,,94r,a enser Ut'iiy Group, Duke Power Company, to espons.>to Follow-up Questions on Ice No),,Q,.JG-001, Rev. 0: Application of the Active

~?~ndenser Ice Mass Technical Specification,"

3.'9and MB3938)," October 10,2002.

icept t C Nos

4.

Let US Cor S. L latoi 1

Ice Condenser Utility Group, Duke Power Company, to n

"Responses to Follow-up Questions on ce l>ijiiI TReport No. ICUG-001, Rev. 0: Application of the Active ConbeA to the Ice Condenser Ice Mass Technical Specification,"

,TAC Nos. MB3369 and MB3938),w October 22, 2002.

TF-

5.

Letter from R.

,~ US Nuclear Re AX-,-

Condenser Uti' 1-~ Ice Mass Man, iL ~'n, Chair, Ice Condenser Utility Group, Duke Power Company, to Xtatory Commission, "Responses to Follow-up Questions on Ice ty Group Topical Report No. ICUG-001, Rev. 0: Application of the Active

'ement Concept to the Ice Condenser Ice Mass Technical Specification,"

Rev. 0 (TAC Nos. MB3369 and MB3938),' November 26, 2002.

6e~itNkal Specification Task Force (TSTF) traveler number 429, Revision 0, dated

.Jauary 27, 2002.

7.

Appendix B to Part 50 - Quality Assurance Criteria for Nuclear Power Plants and Fuel Processing Plants.

8.

NUREGICR-4604, Statistical Methods for Nuclear Material Management, December 1988.

9.

Letter, M. S. Tuckman, Duke Power Company to NRC, 'Nuclear Quality Assurance Program, Amendment 32," dated December 18, 2002.

10.

Letter, B. B. Desai, NRC, to Duke Energy Corporation, Catawba Nuclear tation -

Inspection Report 50-413/02-02, 50-414f02-02," dated July 17, 2002.

Principal Contributors: C, Li A

D. Reddy D. Lude Date: May 6, 2003 NRC

M Dukei Duke Power L WFPower.

Energy Center AcDub EPowevgy C.uwpy P.O. Box 1006 A D.,

E

,V C.,y Caludotte, NC 28201-1006 May 29, 2003 U. S. Nuclear Regulatory Commission Washington, D. C. 20555-0001 Attention: R. Martin (addressee only)

Subject:

Draft Revision 2 to Ice Condenser Utility Group Topical Report No. ICUG-001:

Application of the Active Ice Mass Management Concept to the Ice Condenser Ice Mass Technical Specification (TAC No. MB3379)

Gentlemen:

Please find enclosed a draft of Revision 2 to non-proprietary topical report ICUG-001, "Application of the Active Ice Mass Management Concept to the Ice Condenser Ice Mass Technical Specification." This revision is submitted by the Ice Condenser Utility Group (ICUG) to NRC in response to the staff's draft Safety Evaluation Report (SER) for Revision 0 of the ICUG-001 topical report dated May 6, 2003, and also to commitments made at the May 13, 2003 ICUG/NRC meeting.

The enclosed draft revision 2 to the topical report resolves several issues identified in the draft SER and discussed at the 5/13/03 meeting. Upon staff review and acceptance of the changes presented in this draft, a formal Revision 2 to the ICUG-001 topical report will be issued.

If there are any questions or if additional information is needed, please contact the undersigned at (704) 382-3970 or rsl3ttonQduke-energv.com.

Sincerely, R. S. Lytton Chair, Ice Condenser Utility Group Enclosure xc(w/enclosure): Robert E. Martin (addressee only, 10 copies)

Document Control Desk (one copy)