ORP-70128-VA 

Revision 0

Semi-Annual DNFSB Briefing on 242-A

Evaporator Safety Bases 

Prepared for the U.S. Department of Energy

Assistant Secretary for Environmental Management 

P.O. Box 450 

Richland, Washington 99352 
ORP-70128-VA

Revision 0

Semi-Annual DNFSB Briefing on 242-A Evaporator Safety Bases 

P. Schroder

Department of Energy - Office of River Protection

K. Subramanian

Washington River Protection Solutions

Date Published

March 2024 

To be Presented at

Defense Nuclear Facilities Safety Board (DNFSB) Briefing 

DNFSB

Richland, WA 

03/06/2024 

Prepared for the U.S. Department of Energy

Assistant Secretary for Environmental Management 

P.O. Box 450 

Richland, Washington 99352 

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in and to any copyright covering this paper. 

Release Approval Date 

By Lynn M Ayers at 1:08 pm, Mar 06, 2024
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ORP-70128-VA 

Revision 0
Semi-Annual DNFSB Briefing on 242-A 

Evaporator Safety Bases

Paul Schroder, DOE-ORP, DOE-AMTWO

Karthik Subramanian, WRPS, Chief Engineer

March 6, 2024
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Agenda

• Safety share

• Kick-off (DOE-ORP)

• Background

• Key Accomplishments

• Process/Hazards

• Implemented Interim Control

• Design Status

• Component Testing

• Overview Schedule
3

Background

• 2021 – 2022: Series of Q/A sessions with DNFSB staff

• 7/19/2022: DNFSB letter regarding concerns

• 4/17/2023: DOE Letter to DNFSB with interim controls and planned 

improvements

• 6/27/2023: DNFSB letter requesting semi-annual briefings covering

o Design, procurement, and installation of the planned improvements

o Any emergent technical issues and funding constraints

o Compensatory measures or interim controls to be used

• 9/19/2023: 1st DNFSB semi-annual briefing
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Key Accomplishments Since 9/19/23

• Interim controls (compensatory measures) implemented

• Detailed schedule for planned improvements developed

• Initial conceptual designs and failure modes and effects analysis (FMEAs) have 

been completed for the planned improvements

• Receiving equipment for testing

• There are no emergent technical issues or funding constraints currently identified
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242-A Evaporator Process/Hazards

• Interim controls are implemented in 

preparation for next Evaporator 

campaign

• S1: Overflow of waste leading to 

flammable gas deflagration in Tk-C100 or piping

• S2: Flammable gas deflagration in CA-1

• S3: Seismically induced flammable 

gas deflagration

• S1/S2: Mitigation through dump of 

material from C-A-1 back to the feed 

tank utilizing appropriate safety 

significant (SS) components and 

safety instrumented systems (SISs) • S3: Specific Administrative control 

(SAC) actuated manually viaSS

control room switches or seismically 

qualified SS external switch Reboiler E-A-1

VACUUM

CONDENSERS

E-C-1 E-C-2 E-C-3 

Steam

CONDENSATE 

TANK

TK-C-100 Vapor-Liquid Separator C-A-1

Feed Tank

AW-102 Receiver Tank

Slurry

Pump

LERF

Basin

S1

S2
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Implemented Interim Control Strategy

• Specific Administrative Control (SAC) for Response to Seismic Events (upgraded 

from key element)

o Two SS shutdown hand switches are located in easily accessible locations in the 

control room

o Actuated manually using a seismically qualified SS seismic shutdown hand switch 

located on the southeast exterior concrete wall

• Combustible material SAC for Fires

o Implemented in the 242-A Evaporator condenser room keeping the combustible 

loading below the temperatures at which the SS equipment can be affected

o Removal of combustible materials such as rubber matting

• Defense-in-depth programmatic element for fire detection to respond at 

conservative temperature/temperature change to protect the solenoid 

functionality 
7

Design Status

• Initial conceptual design and failure 

modes and effects analysis (FMEAs) 

have been completed

• Identified critical characteristics and 

safety design requirements 

• Received equipment for testing 

• Beginning development of safety 

requirements documents 

Develop Initial 

Functional 

Requirements

Develop Conceptual 

Design

Perform Initial 

Failure Modes and 

Effects Analysis 

(FMEA) 

Develop Safety 

Requirements 

Documents

Initiate SS 

Procurement

Complete Detailed 

Design

Complete SS 

Procurements

Install Equipment

Acceptance Testing

Completed

Testing of Equipment

Initial Detailed 

Design

Turnover
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Conceptual Design
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Component Testing

• Seismic Switches

o Selected Syscom seismic switches for the conceptual design

o These are the same model previously qualified at Hanford for safety 

service at K Basins

o Existing SIS controller shall be seismically qualified to replace existing 

seismic shutdown relays

o Critical characteristics include safety certifications & instrument trip 

accuracy

o Seismic switches are certified for safety failure rates that help ensure 

that the devices meet safety significant criteria

• Heat Activated Vent Valves

o Selected FireChek®* heat activated pneumatic shut-off valves for the 

conceptual design

o FireChek®* valves are Factory Mutual (FM) approved for but will 

require additional testing to meet SS criteria 

o Critical characteristics include FM approval, device trip accuracy, 

system pressure and time to vent air

*FireChek is a registered trademark of Farrell Equipment & Controls, Inc.
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Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4

FY24 FY25 FY26 FY27

Conceptual Design

Detailed Design Procurement

Component Testing & 

Qualification

Pre-Fabrication & 

Construction Testing

Safety Basis Implementation

Safety Basis Revision and 

Approval

Safety Basis Revision 

Development

Process Hazards Analysis, Control Decision, 

Component Selection

Overview Schedule

• Conceptual design is progressing per schedule

• Equipment for initial testing has been received

• Hazards Analysis is complete with the most recent 

interim control strategy implementation

• Control decision updates to move to engineered 

controls are being developed

• Components have been selected for initial testing

EC-11/EC-12 EC-13/EC-14 EC-15 EC-16/EC-17 EC-18 EC-19 EC-20

Influence of Evaporator Campaigns (EC) • Evaporator campaigns between FY24-FY27 

dependent upon mission needs

• ECs limits facility resource availability

• Each EC is a approximately 6 weeks

• No facility modifications/testing during ECs
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Questions