ML20207Q265

Rev 2 to SAR for Pressurizer Spray Line Defueling Sys

ML20207Q265
Person / Time
Site:	Three Mile Island
Issue date:	01/13/1987
From:	GENERAL PUBLIC UTILITIES CORP.
To:
Shared Package
ML20207Q253	List: ML20207Q252 ML20207Q265
References
4710-3255-86, 4710-3255-86-00, 4710-3255-86-0006-R2, 4710-3255-86-6-R2, NUDOCS 8701270095
Download: ML20207Q265 (15)

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- * . Page 2 of 15 TABLE OF CONTENTS Page No.

1.0 INTRODUCTION

. ........................ 3 1.1 General ........................ 3 1.2 Scope ......................... 4 1.3 Background . . . . . . . . . . . . . . . . . . . . . . . 4 2.0 SYSTEM DESCRIPTION . . .................... 4 2.1 General ........................ 4 2.2 Operation ....................... 5 2.3 Quality Classification . . . . . . . . . . . . . . . . . 5

3.0 TECHNICAL EVALUATION

. .................... 6 3.1 General ........................ 6 3.2 Pressurizer Spray Line Defueling System ........ 6 3.2.1 Line or Hose Break . . . . . . . . . . . . . . 6 3.2.2 Boron Dilution . . .............. 7 3.2.3 Criticality ................. 8 4.0 RADIOLOGICAL AND ENVIRONMENTAL ASSESSMENT .......... 9 4.1 On-Site Dose Assessment ................ 9 4.2 Occupational Exposures . . . . . . . . . . . . . . . . . 10 5.0 SAFETY EVALUATION ...................... 11 5.1 Technical Spec./ Recovery Ops Plan ........... 11 5.2 10CFR50.59 Safety Questions .............. 11

6.0 CONCLUSION

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7.0 REFERENCES

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SAFETY ANALYSIS REPORT I FOR THE PRESSURIZER SPRAY LINE DEFUELING SYSTEM (PSLDS)

1.0 INTRODUCTION

1.1 General The Pressurizer Spray Line Defueling System (PSLDS) is designed to remove fuel fines and/or core debris from the Pressurizer Spray Line. The source of flush water will be from the Defueling Water Cleanup System. A flexible hose will run from the newly installed Defueling Water Clean-up System (DWCS) tie-in downstream of the filter canisters and end at a new tie-in attached to the Pressurtzer Spray Line. Defueling will consist of flushing the Pressurizer Spray Line in a series of steps to adequately remove fuel fines and debris in each different flow path from the spray i

line tie-in.

The OWCS Filter Train 8 will be used for the PSLDS. Filter Train A is independent of Pressurizer Spray Line defueling activities. No physical changes are made or restrictions placed on Filter Train A. The ability to filter Reactor Vessel inventory (via Train A) during spray line defueling ensures that ex-vessel defueling will not interfere with in-vessel defueling efforts.

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, Page 4 of 15 1.2 Scope The scope of this document includes the operation of the PSLDS, the components of the PSLDS, and its tie-ins to the DWCS and Pressurizer Spray Line. This safety analysis report is applicable only during the recovery mode as the PSLDS is a temporary system ,

required to support the ex-vessel defueling efforts and will be removed prior to restart of the plant.

1.3 Background

Due to the effects of the TMI-2 accident on March 28, 1979; fuel and/or core debris have been located throughout the Nuclear Steam Supply System (NSSS). A potential location for some of the fuel / core debris is the Pressurizer Spray Line. The Pressurizer Spray Line is a logical starting point for the defueling of ex-vessel components. Due to the small size of the spray line (2 1/2 inch), flushing is considered to be the most efficient and cost effective method of defueling.

2.0 SYSTEM DESCRIPTION 2.1 General The Pressurizer Spray Line Defueling System is designed to carry flush water from the DHCS Filter Train B to the Pressurizer Spray Line. The system's only function is to relocate 14758 RP

SA 4710-3255-86-0006 Page 5 of 15 fuel fines and/or core debris (in the spray line and by-pass line) to the Pressurizer Vessel and Cold Leg Loop 2A for future fuel removal.

1 2.2 Operation The Pressurizer Spray Line is flushed via a connection to the l DHCS. The source water from the DHCS will be supplied at a flow rate of 200 gpm. The velocity developed by the 200 gpm flow rate would be approximately 18 fps for a 2 1/2" sch 160 pipe (spray line). With this velocity, a flush time of 30 minutes per flowpath will be used. Considering the flow rate, velocity and duration of this operation, the Pressurizer Spray Line volume will be displaced (defueled) over 580 times during a single flush period. This should be sufficient to assure that most of the loose core / fuel debris or any particulate will be relocated for future defueling.

2.3 Quality Classification The quality classification of the FSLDS is Important To Safety (ITS). ITS as used in this document is defined in the THI-2 Recovery Quality Classification List.

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3.0 TECHNICAL EVALUATION

3.1 General i

The PSLDS is totally contained within areas that have controlled ventilation and area isolation capability. This limits the environmental impact of the syste,m during normal system operations, shutdown or postulated accident conditions. The effects of the potential PSLDS failures will be supplied below on a case-by-case  ;

basis.

The system failures analyzed are reactor vessel inventory loss via line/ hose break, boron dilution, and criticality. The failure modes not covered by this safety analysis, but described in the DHCS TER (see Reference 1. Section 3.2) are loss of power and loss of instrumentation / instrument air. No unacceptable consequences were found to result from the operation of the PSLDS provided that proper administrative control is maintained, t

3.2 Pressurizer Spray Line Defueling System Failures 3.2.1 Line or Hose Break The principle consequence of any line/ hose break is loss t I

of reactor vessel inventory. This system is designed to mitigate the consequences of such an accident to the 4

extent possible.

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,- Page 7 of 15 In case of a hose or line rupture on the PSLDS, the DHCS

, will trip the reactor vessel pumps on IIF low level and alarm at control panels located in the control room and the Fuel Handling Building. This type of accident could deliver approximately 500 to 1000 gallons of reactor b vessel water to the area of the rupture. The affected area would be within the Reactor Building, which has a sump to contain the spill.

The recovery from this event would be accomplished by isolating the ruptured section and replacing the ruptured hose or pipe.

l 3.2.2 Boron Dilution -

The only credible means of attaining criticality of the fuel contained in the vessel is by deboration of the reactor coolant water. Deboration could develop from the misconnection of the defueling flexible hose to a nonborated source. To lessen the possibility of a misconnection, all valves, quick disconnect fittings and hoses (both ends).wlli be properly tagged and/or color coded. All valves used to operate / regulate and isolate the PSLDS shall be monitored by the Control Room in accordance with Procedure 4000-ADM-3020.04. In addition to valve monitoring, all hose connections as well as 14758 RP i

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I l valve alignment will be visually inspected prior to l

system start-up to ensure that the flush water flow path is as intended by design.

l 3.2.3 Criticality l

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- Fuel accumulation in the PSLDS is precluded by using a high velocity water flow through the system. This should b

prevent the settling of fuel fines / debris in the system.

During the course of the TMI-2 Recovery Operations, the Reactor Vessel inventory has been bled and fed a number j of times. This cycling of the vessel water level would have caused the pressurizer water to combine with the Reactor Vessel water and create a more uniform boron concentration between the two vessels. Additionally, the Pressurizer Spray Line Defuftling System, by virtue of its operation, will promote circulation of the vessel inventory; thus resulting in more uniform boron concentration. Hence, boron dilution / concentration is not a notable concern.

l The PSLDS will transport fuel fines into the Pressurizer Vessel and Cold Leg Loop 2A. Under optimum conditions, a minimum of 70 kg of fuel is required for criticality l

(Ref. 6). The Pressurizer Spray Line is expected to l contain a maximum of 0.1 kg of fuel, while the 14758 RP l

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SA 4710-3255-86-0006 Page 9 of 15 Pressurtzer Vessel and Reactor Coolant Cold Leg Loop 2A are expected to contain a maximum of 25 kg and 0.1 kg, respectively (Reference 5, Table 2.3-1) . Therefore, the small amount of fuel in the spray line could accumulate in either location, and the total amount of fuel would be less than the 70 kg limiting value. Therefore, a possible critical configuration of fuel debris is unitkely. In the event that 70 kg was introduced to the system, the boron concentration present would preclude a criticality.

4.0 RADIOLOGICAL AND ENVIRONMENTAL ASSESSMENT 4.1 On-Site Dose Assessment

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The potential exists that defueling the Pressurizer Spray Line may increase the specific activity in the reactor vessel water. This could occur during operation of the PSLDS through disturbance of the core debris by the introduction of flush water into the Cold Leg Loop 2A, Fuel material greater than 0.5 microns ar.d other soli.ble fission products should be removed by the operation of the DHCS Filter Train A.

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4.2 Occupational Exposures Operation of the DWCS Train A may reduce the occupational exposure during the defueling of the Pressurizer Spray Line by maintaining low specific activities in the reactor vessel (see Reference 1, Section 4.3).

The following table provides an estimate of the man-hours and man-rem associated with the installation, operation and removal of the Pressurizer Spray Line Defueling System. These estimates are based upon current man-hour projections:

LOCATION ACTIVITY MAN-HOURS (mR/Hr) y MAN-REM R.B. Floor at Installation 4 100 mrem .4 Elev. 348'-3" Operation 0 --

Removal 3 .3 "A" D-Ring at Installatlon 1 80 mrem .08 Elev. 367'-4" Operation 0 --

Removal .75 .06 Pressurizer Installation .5 50 mrem .025 Missile Shield at Operation 3 .15 Elev. 370'-4" Removal .5 .025 Pressurizer Installation 5 1500 mrem 7.5 Platform at Elev. 355'-3" Operation Removal 1.5 3.5

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TOTAL (1) 16.140_

• There is a 12 Rem source present in the proximity of the grating platform at elevation 349'-9" south of the Pressurizer Vessel. This source must be adequately shleided prior to commencing the defueling activities.

(1) This is if valves operate automatically. If manual operation of electrically operated valves is required, an additional g

1.5 + 2.0 manrem will be required.

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. SA 4710-3255-86-0006 Page 11 of 15 The total man-rem attributable to the installation, operation, and removal of the PSLDS, as a whole, is expected to be between 13.6 and 25.2 man-rem. The estimate is based upon a total of 16.14 man-rem increased by 20% for RadCon coverage and allowing i 30% due to uncertaintles. (These values are based on the assumption that valves RC-VI and RC-V3 operate automatically. If manual operation of these valves is required, an additional 1.5 to 2.0 man-rem will be required to be added to the 16.14 man-rem.)

Personnel protection for airborne and other potential contamination generated by the installation, use and/or removal of the PSLDS will be addressed in the appropriate plant procedures.

5.0 SAFETY EVALUATION 5.1 Technical Specifications / Recovery Operations Plan No additional Technical Specifications / Recovery Operations Plan changes are required to install and operate the PSLDS.

5.2 Safety Questions (10CFR50.59) 10CFR50, Paragraph 50.59, permits the holder of an operating license to make changes to the facility or perform a test or experiment, provided the change, test, or experiment is determined not to be an unreviewed safety question and does not involve a modification of the plant technical specifications.

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, Page 12 cf 15 A proposed change involves an unreviewed safety question if:

r a) The possibility of the consequence of an accident or malfunction of equipment important to safety previously evaluated in the safety analysis report may be increased; or l

b) The possibility for an accident or malfunction of a different '

type than any evaluated previously in the safety analysis report may be created; or I

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c) The margin of safety, as defined in the basis for any l technical specification, is reduced.

The Pressurizer Spray Line Defueling System (PSLOS) does not increase the probability of occurrence or the consequences of an

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l accident or malfunction of equipment important to safety previously l

evaluated in a safety analysis report. The system failures evaluated are presented in Section 3.2 of this report. The PSLDS was found to have no failures that would increase the probability i

1 of occurrence or the consequences of an accident or malfunction of {

l equipment important to safety (ITS). ,

r The possibility of an accident or malfunction of a different type than previously evaluated in this safety analysis report is not created by the existence of the PSLOS. The PSLOS is essentially a flushing system to transport fuel fines and/or core debris from the  !

Pressurizer Spray Line to the Pressurizer Vessel and Cold Leg  ;

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• SA 4710-3255-86-0006 Page 13 of 15 Operation of the Pressurizer Spray Line Defueling System does not result in a reduction in the margin of safety as defined in the bases for the Technical Specifications (Reference 4). Liquid effluents will not be released to the environment directly from the PSLDS operations. The effluents from the operation of the PSLDS will be returned to the sources in order to maintain proper specific activity and water levels. The results of the radioactive l  !

release analysis presented in the DWC Technical Evaluation Report (Reference 1) therefore bound the releases from the PSLDS. Since l no change in the maximum permissible concentrations specified in Appendix B of the Techn.lcal Specifications (Reference 4) was l required for the DHCS operation and since the PSLDS operation is l

bounded by the DHCS operation, no changes are required for the PSLDS operation.

Based on the above, the installation and operation of the PSLDS does not present an unreviewed safety question as defined in 10CFR50.59.

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6.0 CONCLUSION

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Based on this Safety Analysis Report, the Pressurizer Spray Line may be 1

defueled without any adverse safety effects.

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The effects of,the potential failures of the PSLDS identified in

) Section 3.2 were found acceptable, provided that proper administrative  !

t l control is maintained. All possible modes of failure have been j

! i incorporated into the design of the PSLDS and/or are bounded by the - t i

i operation of the DHCS. Therefore, the installation, operation and i removal of the PSLOS should provide minimal effects to personnel and no I effects to the public, j

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7.0 REFERENCES

1. TER 15737-2-G03-106 Rev. 9. "TMI-2 Division Technical Evaluation Report for the Defueling Water Cleanup System."

2. DC 3255-86-0003 Rev. 2, "TMI-2 Design Criteria for Pressurtzer Spray Line Defueling System."

3. Code of Federal Regulations 10 (Energy) Part 50 Paragraph 50.59, Revised as of January 1, 1985.

4. Three Mlle Island Nuclear Station Unit 2 Operating License Number DPR-73 with the Recovery Technical Specification.

5. TP0/THIh186Rev.O,"Astrategyfortherecoveryprogramcompletion and post-recovery configuration;" Volume 2 - Technical Basts.

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6. Technical Plan for Ex-RCS Criticality Safety, TP0/TMI-132, THI-2 Technical Planning Department, Nov. 1985.

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