RPM Neutron Detector Helium-3 (He3) Tube Replacement

Last Updated: 04/24/2025 1:45 AM

The following table lists all the components that make up the document.

Title	Type	Status	Last Updated
Rapiscan PM-700 Pedestrian Monitor	Device	Published	06/20/2024 11:38 AM
Rapiscan VM-250 Vehicle Monitor	Device	Published	10/14/2024 9:50 AM
Rapiscan TM-850 Rail Monitor	Device	Published	09/18/2024 10:28 AM
7621 - 1401 - Establish Initial Conditions; Remark:	Procedure Step	Published	06/29/2023 5:37 PM
1401 - Establish Initial Conditions	Instruction	Published	09/30/2022 3:14 PM
7268 - 7231 - Close lane; Remark:7233	Procedure Step	Published	04/27/2023 7:01 PM
9053 - Warning : Traffic should temporarily be rerouted or halted during conduction of this pr...	Annotation	Published	09/27/2023 9:09 AM
7231 - Close lane	Instruction	Published	04/18/2023 1:00 PM
7233 - Use orange safety (traffic control) cones to setup barriers. Practice establi...	Remark	Published	04/24/2023 12:18 PM
7269 - 7232 - Open RPM door; Remark:7234	Procedure Step	Published	04/27/2023 7:02 PM
7232 - Open RPM door	Instruction	Published	04/18/2023 1:02 PM
7234 - Open all doors needed to access components.	Remark	Published	04/19/2025 7:48 PM
7454 - 7290 - Disable tamper switches; Remark:7416	Procedure Step	Published	06/02/2023 5:25 PM
7290 - Disable tamper switches	Instruction	Published	05/01/2023 8:14 AM
7416 - Use a magnet to disable tamper switches for all open doors. Use adhesive tape...	Remark	Published	06/02/2023 1:18 PM
8561 - 7291 - Disable both infrared occupancy sensors; Remark:8514	Procedure Step	Published	09/18/2023 12:05 AM
5291 - Note : It is good practice to verify all cables and connectors are labeled prior to ...	Annotation	Published	10/24/2022 8:35 AM
7291 - Disable both infrared occupancy sensors	Instruction	Published	05/01/2023 8:15 AM
8514 - Verify sensors mounted in control pillar door are receivers.	Remark	Published	09/29/2023 11:52 AM
9205 - To disconnect sensor cable, turn collar counterclockwise and pull away from s...	Remark	Published	09/29/2023 11:52 AM
8221 - 7676 - Brief system operators on expected work, duration, anticipated alarms, and fa...; Remark:	Procedure Step	Published	09/01/2023 9:26 PM
7676 - Brief system operators on expected work, duration, anticipated alarms, and fa...	Instruction	Published	07/01/2023 11:39 PM
8591 - 8515 - Uninstall Faulty Neutron Tube; Remark:	Procedure Step	Published	09/18/2023 12:10 AM
8515 - Uninstall Faulty Neutron Tube	Instruction	Published	09/17/2023 7:24 PM
8562 - 8516 - Disconnect cable from faulty helium-3 (He3) tube; Remark:8517	Procedure Step	Published	09/17/2023 10:38 PM
8516 - Disconnect cable from faulty helium-3 (He3) tube	Instruction	Published	09/17/2023 7:25 PM
8517 - Push toward connection, turn coupling nut counterclockwise, and pull away fro...	Remark	Published	09/17/2023 7:30 PM
8563 - 8518 - Remove four (4) front panel screws; Remark:8519	Procedure Step	Published	09/17/2023 10:39 PM
8518 - Remove four (4) front panel screws	Instruction	Published	09/17/2023 7:32 PM
8519 - Use a large Phillips (PH3) screwdriver. There should be four (4) screws, but ...	Remark	Published	09/17/2023 7:37 PM
8564 - 6748 - Remove front panel; Remark:	Procedure Step	Published	09/17/2023 10:39 PM
6748 - Remove front panel	Instruction	Published	12/09/2022 3:49 PM
8565 - 8520 - Remove stabilizing brace screws; Remark:8521	Procedure Step	Published	09/17/2023 10:40 PM
8520 - Remove stabilizing brace screws	Instruction	Published	09/17/2023 7:40 PM
8521 - There should be two stabilizing braces for each He3 tube; configurations migh...	Remark	Published	09/17/2023 7:45 PM
8566 - 8523 - Loosen bracket screw (if applicable); Remark:8525	Procedure Step	Published	09/17/2023 10:42 PM
8522 - Caution : Tube may fall out of detector assembly when bracket screw is removed.	Annotation	Published	09/17/2023 7:59 PM
9605 - Note : This step is only needed if cleaning He3 tube from upper detector.	Annotation	Published	04/13/2025 6:03 PM
8523 - Loosen bracket screw (if applicable)	Instruction	Published	09/17/2023 8:00 PM
8525 - If there is more than one screw, completely remove one. Use medium Phillips (...	Remark	Published	09/29/2023 12:12 PM
8567 - 8526 - Rotate bracket (if applicable); Remark:8527	Procedure Step	Published	09/17/2023 10:43 PM
8526 - Rotate bracket (if applicable)	Instruction	Published	09/17/2023 8:13 PM
8527 - Rotate neutron bracket	Remark	Published	04/13/2025 5:58 PM
8568 - 8528 - Remove He3 tube; Remark:8529	Procedure Step	Published	09/17/2023 10:44 PM
8528 - Remove He3 tube	Instruction	Published	09/17/2023 8:24 PM
8529 - Slide tube up through hole and then pull out of moderator.	Remark	Published	04/13/2025 6:11 PM
8569 - 8530 - Remove stabilizing braces; Remark:8531	Procedure Step	Published	09/17/2023 10:45 PM
8530 - Remove stabilizing braces	Instruction	Published	09/17/2023 8:31 PM
8531 - Slide stabilizing braces off He3 tube.	Remark	Published	09/17/2023 8:32 PM
3397 - 3395 - Label faulty component; Remark:3396	Procedure Step	Published	07/21/2024 6:59 AM
3395 - Label faulty component	Instruction	Published	08/07/2021 11:07 AM
3396 - Use tag or tape. Include date of removal, description of failure symptoms, co...	Remark	Published	08/09/2021 11:35 AM
8571 - 8533 - Install New He3 Tube; Remark:	Procedure Step	Published	09/17/2023 10:46 PM
8533 - Install New He3 Tube	Instruction	Published	09/17/2023 8:43 PM
8572 - 8534 - Place stabilizing braces onto new He3 tube; Remark:	Procedure Step	Published	09/17/2023 10:47 PM
8534 - Place stabilizing braces onto new He3 tube	Instruction	Published	09/17/2023 8:44 PM
8573 - 8535 - Insert new He3 tube into moderator; Remark:	Procedure Step	Published	09/17/2023 10:48 PM
8535 - Insert new He3 tube into moderator	Instruction	Published	09/17/2023 8:46 PM
8574 - 8526 - Rotate bracket (if applicable); Remark:8536	Procedure Step	Published	09/17/2023 10:48 PM
8536 - Rotate He3 tube bracket	Remark	Published	09/17/2023 8:48 PM
8575 - 8537 - Tighten bracket screw (if applicable); Remark:8538	Procedure Step	Published	09/17/2023 10:49 PM
8537 - Tighten bracket screw (if applicable)	Instruction	Published	09/17/2023 8:50 PM
8538 - Use medium Phillips (PH2) screwdriver.	Remark	Published	09/17/2023 8:51 PM
8576 - 8539 - Reinstall stabilizing braces screws; Remark:8540	Procedure Step	Published	09/17/2023 10:50 PM
8539 - Reinstall stabilizing braces screws	Instruction	Published	09/17/2023 8:53 PM
8540 - Use medium Phillips (PH2) screwdriver.	Remark	Published	09/17/2023 8:54 PM
8577 - 8541 - Reinstall front panel with four (4) screws; Remark:8542	Procedure Step	Published	09/17/2023 10:51 PM
8541 - Reinstall front panel with four (4) screws	Instruction	Published	09/17/2023 8:56 PM
8542 - Use large Phillips (PH3) screwdriver.	Remark	Published	09/17/2023 8:59 PM
8578 - 8543 - Reconnect cable to He3 tube; Remark:8544	Procedure Step	Published	09/17/2023 10:52 PM
5553 - Caution : Correct placement of connectors and wiring is critical to proper operation.	Annotation	Published	10/28/2022 2:19 PM
8543 - Reconnect cable to He3 tube	Instruction	Published	09/17/2023 9:01 PM
8544 - Rotate to align connector notches. Push toward connection and turn coupling n...	Remark	Published	09/17/2023 9:05 PM
7279 - 7249 - Return equipment to normal operating condition; Remark:	Procedure Step	Published	04/27/2023 4:13 PM
7249 - Return equipment to normal operating condition	Instruction	Published	04/08/2025 3:22 PM
7280 - 7250 - Power on RPM; Remark:7251	Procedure Step	Published	04/27/2023 4:14 PM
7250 - Power on RPM	Instruction	Published	05/01/2023 8:31 AM
7251 - Move LD-260 switch to ON position. The LED PWR ON	Remark	Published	05/10/2023 3:14 PM
7281 - 7252 - Verify RPM start-up; Remark:7253	Procedure Step	Published	04/20/2025 3:26 PM
7252 - Verify RPM start-up	Instruction	Published	04/27/2023 2:23 PM
7253 - RPM will perform a power on self-test (POST) and collect a background radiati...	Remark	Published	05/10/2023 3:14 PM
7282 - 7254 - Confirm network connection; Remark:7255	Procedure Step	Published	04/27/2023 4:15 PM
7254 - Confirm network connection	Instruction	Published	04/27/2023 2:22 PM
7255 - Contact operators to confirm communications have been reestablished between RPM ...	Remark	Published	05/10/2023 3:15 PM
8579 - 8545 - Isolate new He3 tube; Remark:8547	Procedure Step	Published	09/17/2023 10:53 PM
8546 - Caution : Do not disconnect cable from new tube	Annotation	Published	09/17/2023 9:17 PM
8545 - Isolate new He3 tube	Instruction	Published	09/17/2023 9:16 PM
8547 - Disconnect cables from all He3 tubes in moderator (white box) except	Remark	Published	09/17/2023 9:19 PM
8580 - 8548 - Navigate to SHOW COUNTS for neutron channels; Remark:8549	Procedure Step	Published	09/17/2023 10:57 PM
8548 - Navigate to SHOW COUNTS for neutron channels	Instruction	Published	09/17/2023 9:22 PM
8549 - On SC-770, press 01234# Then, press 2:	Remark	Published	09/17/2023 9:26 PM
8581 - 8550 - Place neutron source on neutron detector; Remark:8551	Procedure Step	Published	09/17/2023 10:57 PM
8550 - Place neutron source on neutron detector	Instruction	Published	09/17/2023 9:28 PM
8551 - Secure source to middle of detector with adhesive tape.	Remark	Published	09/17/2023 9:31 PM
8582 - 9606 - Verify counts from cleaned He3 tube; Remark:8553	Procedure Step	Published	09/17/2023 10:58 PM
9606 - Verify counts from cleaned He3 tube	Instruction	Published	10/11/2023 11:33 AM
8553 - Neutron counts will increase on the channel with the new He3 tube	Remark	Published	09/17/2023 9:34 PM
8583 - 2581 - Remove radioactive source; Remark:	Procedure Step	Published	09/17/2023 11:00 PM
2581 - Remove radioactive source	Instruction	Published	08/11/2021 3:52 PM
8584 - 8458 - Exit programming mode; Remark:8554	Procedure Step	Published	09/17/2023 11:00 PM
8458 - Exit programming mode	Instruction	Published	09/15/2023 4:21 PM
8554 - On SC-770, press # button until main controller screen is di...	Remark	Published	09/17/2023 9:40 PM
8585 - 8555 - Reconnect all neutron detectors; Remark:8556	Procedure Step	Published	09/17/2023 11:01 PM
8555 - Reconnect all neutron detectors	Instruction	Published	09/17/2023 9:53 PM
8556 - Connecting neutron cable	Remark	Published	09/17/2023 9:55 PM
8586 - 8557 - Perform functional compliance test; Remark:8558	Procedure Step	Published	09/17/2023 11:02 PM
8557 - Perform functional compliance test	Instruction	Published	09/17/2023 10:00 PM
8558 - DET-RPM-RAP-RM05, RPM Functional Compliance Test.	Remark	Published	09/17/2023 10:02 PM
8588 - 7305 - Enable both infrared occupancy sensors; Remark:8559	Procedure Step	Published	09/17/2023 11:04 PM
7305 - Enable both infrared occupancy sensors	Instruction	Published	05/01/2023 8:33 AM
8559 - To reconnect sensor cable, align connectors, push towards sensor, and turn co...	Remark	Published	09/29/2023 12:05 PM
8589 - 7310 - Enable tamper switches; Remark:7348	Procedure Step	Published	09/17/2023 11:07 PM
7310 - Enable tamper switches	Instruction	Published	05/01/2023 8:36 AM
7348 - Remove all magnets and/or adhesive tape from door switches.	Remark	Published	09/17/2023 10:23 PM
7283 - 7256 - Close and lock all RPM doors; Remark:	Procedure Step	Published	09/01/2023 11:45 PM
7256 - Close and lock all RPM doors	Instruction	Published	04/27/2023 2:21 PM
7842 - 7820 - Inform system operators upon completion of maintenance action; Remark:	Procedure Step	Published	07/07/2023 11:15 PM
7820 - Inform system operators upon completion of maintenance action	Instruction	Published	07/07/2023 10:02 PM
322 - 321 - Document maintenance actions; Remark:	Procedure Step	Published	06/17/2021 9:49 AM
321 - Document maintenance actions	Instruction	Published	04/21/2025 11:19 AM
2869 - 2585 - Document maintenance performed; Remark:2866	Procedure Step	Published	06/18/2021 5:58 PM
2585 - Document maintenance performed	Instruction	Published	07/09/2021 12:15 PM
2866 - Record observations, times, and results for the maintenance report.	Remark	Published	04/21/2025 11:39 AM
4706 - 4705 - Submit report; Remark:4864	Procedure Step	Published	06/29/2022 9:50 AM
4705 - Submit report	Instruction	Published	06/29/2022 9:50 AM
4864 - As specified by management or contractual obligations.	Remark	Published	07/28/2022 1:36 PM
Corrective Maintenance Procedure	Document Type	Published	03/02/2020 3:32 PM
minutes	Duration	Published	05/26/2022 11:41 AM
Upon failure of neutron detector He3 tube	Frequency	Published	09/17/2023 11:37 PM
Warning	Annotation Type	Published	03/02/2020 3:25 PM
Note	Annotation Type	Published	03/02/2020 3:25 PM
Caution	Annotation Type	Published	03/02/2020 3:24 PM
Technician 2	Skill Level	Published	04/09/2020 1:17 AM
Keys to access RPM	Replacement Parts	Published	04/27/2023 6:56 PM
Magnets and adhesive tape to disable door tamper switches	Replacement Parts	Published	06/02/2023 10:08 PM
Medium Phillips (PH2) screwdriver	Tools	Published	04/24/2020 4:40 PM
Large Phillips (PH3) screwdriver	Tools	Published	09/17/2023 11:37 PM
Ladder: 2 meters, 6 feet tall; non-conducting	Replacement Parts	Published	09/01/2023 9:34 PM
Orange/yellow safety vest	Replacement Parts	Published	04/27/2023 6:56 PM
Safety shoes	Replacement Parts	Published	04/27/2023 6:56 PM
Gloves	Replacement Parts	Published	05/10/2023 3:28 PM
Protective headwear: glasses, hard hat	Replacement Parts	Published	05/10/2023 3:31 PM
Orange traffic cones	Replacement Parts	Published	04/27/2023 6:56 PM
Disable tamper switch	Image	Published	09/07/2023 8:22 PM
Disable Tamper Switch	Image	Published	06/02/2023 2:28 PM
Infrared Receiver	Image	Published	09/17/2023 7:09 PM
Infrared Receiver DC	Image	Published	09/29/2023 11:47 AM
Infrared Disconnect Sensor Cable	Image	Published	09/17/2023 7:11 PM
Infrared Sensor Disconnect	Image	Published	09/17/2023 7:12 PM
Neutron Connector Removal	Image	Published	09/17/2023 7:28 PM
Neutron Panel Screws	Image	Published	09/17/2023 7:36 PM
Neutron Brace	Image	Published	09/17/2023 7:45 PM
Loosen Neutron Bracket	Image	Published	09/17/2023 7:53 PM
Loosen Neutron Bracket	Image	Published	09/17/2023 7:54 PM
Rotate Neutron Bracket_1	Image	Published	09/17/2023 7:56 PM
Rotate Neutron Bracket	Image	Published	09/17/2023 7:57 PM
Remove He3 Tube	Image	Published	09/17/2023 8:22 PM
Pull He3 Tube	Image	Published	09/17/2023 8:23 PM
Remove He3 Tube Braces	Image	Published	09/17/2023 8:29 PM
Return Rotated Neutron Bracket	Image	Published	09/17/2023 8:41 PM
Reconnect Neutron Cables	Image	Published	09/17/2023 9:03 PM
LD-260 Disconnect Switch Power On	Image	Published	05/04/2023 3:37 PM
Source on Neutron Detector	Image	Published	09/17/2023 9:29 PM
SC-770 Neutron Counts	Image	Published	09/17/2023 9:34 PM
Infrared Connection	Image	Published	09/29/2023 12:02 PM
Infrared Cable Installation	Image	Published	09/17/2023 10:12 PM
Infrared Sensor Cable	Image	Published	09/17/2023 10:13 PM
Remove all magnets and or adhesive tape from door switches	Image	Published	09/08/2023 4:18 PM
Remove Magnet on Tamper Switch	Image	Published	06/02/2023 4:31 PM

DET-RPM-RAP-CM21

Replace neutron detector helium-3 (He3) tube on radiation portal monitor (RPM).

Equipment Hierarchy

Rapiscan PM-700 Pedestrian Monitor

Rapiscan VM-250 Vehicle Monitor

Rapiscan TM-850 Rail Monitor

Frequency

Upon failure of neutron detector He3 tube

Technician Level

Technician 2

x 1

Duration

Time increment

minutes

Length of time

Tools Required

Keys to access RPM

Magnets and adhesive tape to disable door tamper switches

Medium Phillips (PH2) screwdriver

Large Phillips (PH3) screwdriver

Ladder: 2 meters, 6 feet tall; non-conducting

Orange/yellow safety vest

Safety shoes

Gloves

Protective headwear: glasses, hard hat

Orange traffic cones

Materials Required

Rapiscan helium-3 (He3) neutron detector tube (Rapiscan Part #6720C)

Sealed neutron source: Cf-252 activity 37 - 185 kBq (1.0 0 5.0 µCi) (2,000 - 20,000 n/s [neutrons/second]) or approved alternative

Adhesive tape to secure neutron source to detector

Originators

Craig Stinson

Brian Tucker

Originating Organization

ORNL; PNNL

Approver

Cody Hostick

Safety Concerns

Traffic

Final Documentation

Corrective Maintenance Report

Departmental Coordination

Prior to arrival, notify operators concerning expected work, duration, and anticipated alarms and fault indications.

Date of Origin

2021-07-01

Version

0.00

Preparation

Step 1

Main Step

7621 - 1401 - Establish Initial Conditions; Remark:

Step 00

1401 - Establish Initial Conditions

Establish Initial Conditions

7268 - 7231 - Close lane; Remark:7233

9053 - Warning : Traffic should temporarily be rerouted or halted during conduction of this pr...

Type

Warning

Traffic should temporarily be rerouted or halted during conduction of this procedure to ensure maintenance provider safety and to prevent unscreened vehicles from passing.

Step 00

7231 - Close lane

Close lane

7233 - Use orange safety (traffic control) cones to setup barriers. Practice establi...

Use orange safety (traffic control) cones to setup barriers. Practice established safety protocols.

7269 - 7232 - Open RPM door; Remark:7234

Step 00

7232 - Open RPM door

Open RPM door

7234 - Open all doors needed to access components.

Open all doors needed to access components.

7454 - 7290 - Disable tamper switches; Remark:7416

Step 00

7290 - Disable tamper switches

Disable tamper switches

7416 - Use a magnet to disable tamper switches for all open doors. Use adhesive tape...

Use a magnet to disable tamper switches for all open doors. Use adhesive tape to disable older mechanical switches.

8561 - 7291 - Disable both infrared occupancy sensors; Remark:8514

5291 - Note : It is good practice to verify all cables and connectors are labeled prior to ...

Type

Note

It is good practice to verify all cables and connectors are labeled prior to disconnection.

Step 00

7291 - Disable both infrared occupancy sensors

Disable both infrared occupancy sensors

8514 - Verify sensors mounted in control pillar door are receivers.

Verify sensors mounted in control pillar door are receivers.

9205 - To disconnect sensor cable, turn collar counterclockwise and pull away from s...

To disconnect sensor cable, turn collar counterclockwise and pull away from sensor.

8221 - 7676 - Brief system operators on expected work, duration, anticipated alarms, and fa...; Remark:

Step 00

7676 - Brief system operators on expected work, duration, anticipated alarms, and fa...

Brief system operators on expected work, duration, anticipated alarms, and fault indications before starting work

Step 2

Main Step

8591 - 8515 - Uninstall Faulty Neutron Tube; Remark:

Step 00

8515 - Uninstall Faulty Neutron Tube

Uninstall Faulty Neutron Tube

8562 - 8516 - Disconnect cable from faulty helium-3 (He3) tube; Remark:8517

5291 - Note : It is good practice to verify all cables and connectors are labeled prior to ...

Type

Note

It is good practice to verify all cables and connectors are labeled prior to disconnection.

Step 00

8516 - Disconnect cable from faulty helium-3 (He3) tube

Disconnect cable from faulty helium-3 (He3) tube

8517 - Push toward connection, turn coupling nut counterclockwise, and pull away fro...

Push toward connection, turn coupling nut counterclockwise, and pull away from connection.

8563 - 8518 - Remove four (4) front panel screws; Remark:8519

Step 00

8518 - Remove four (4) front panel screws

Remove four (4) front panel screws

8519 - Use a large Phillips (PH3) screwdriver. There should be four (4) screws, but ...

Use a large Phillips (PH3) screwdriver. There should be four (4) screws, but quantity may vary. Retain screws for reinstallation.

8564 - 6748 - Remove front panel; Remark:

Step 00

6748 - Remove front panel

Remove front panel

8565 - 8520 - Remove stabilizing brace screws; Remark:8521

Step 00

8520 - Remove stabilizing brace screws

Remove stabilizing brace screws

8521 - There should be two stabilizing braces for each He3 tube; configurations migh...

There should be two stabilizing braces for each He3 tube; configurations might vary. Use a medium Phillips (PH2) screwdriver. Retain screws.

8566 - 8523 - Loosen bracket screw (if applicable); Remark:8525

8522 - Caution : Tube may fall out of detector assembly when bracket screw is removed.

Type

Caution

Tube may fall out of detector assembly when bracket screw is removed.

9605 - Note : This step is only needed if cleaning He3 tube from upper detector.

Type

Note

This step is only needed if cleaning He3 tube from upper detector.

Step 00

Main Step

Correct placement of connectors and wiring is critical to proper operation.

Step 00

8543 - Reconnect cable to He3 tube

Reconnect cable to He3 tube

8544 - Rotate to align connector notches. Push toward connection and turn coupling n...

Rotate to align connector notches. Push toward connection and turn coupling nut clockwise.

Operation

Step 4

Main Step

Do not disconnect cable from new tube

Step 00

Correct placement of connectors and wiring is critical to proper operation.

Step 00

Main Step

Corrective Maintenance Procedure

Percent Complete

100.00

Percent Complete W/Media

100.00