Sealed Source and Device (SS&D) Registration

Q: What is SS&D registration?

Sealed Source and Device (SS&D) registration is the NRC or Agreement State process of evaluating the radiation-safety design of a sealed source or the device that contains it and issuing a registration certificate, commonly called an SS&D sheet. The certificate is entered into the National Sealed Source and Device Registry and defines the conditions under which the source or device may be used safely.

Q: What does an SS&D certificate specify?

The SS&D certificate identifies the source or device, the radionuclide and maximum activity, the prototype test results and source classification, conditions of normal use, leak-test method and interval, labeling, and any limits on servicing. Operating outside those conditions can void the registration basis and create a regulatory and safety problem.

Q: Who supports SS&D compliance at a facility?

The radiation safety officer, supported by a qualified or board-certified medical physicist, confirms that each source and device is registered, that use stays within the SS&D certificate, that leak tests and inventories are current, and that license records reference the correct manufacturer and model numbers.

Before a facility ever turns on a blood irradiator, mounts a gauge, or stores a calibration source, that source and the device that holds it have already been tested, evaluated, and registered. Sealed Source and Device (SS&D) registration is the regulatory step that converts a radiation-safety design evaluation into a certificate — the SS&D sheet — that is entered into the National Sealed Source and Device Registry and defines exactly how the source or device may be used. For a radiation safety officer (RSO) and medical physicist, the SS&D certificate is not paperwork to file and forget: it sets the leak-test interval, the servicing limits, and the conditions that keep the source's safety basis valid.¹²

This guide explains what SS&D registration is, what the certificate contains, how a user references it on a license, and the practical responsibilities that follow.

Introduction

A sealed source is radioactive material permanently bonded or encapsulated in a capsule designed to prevent leakage or escape of the material. A device is the equipment that contains the sealed source and controls its use — a gauge, an irradiator, a bone-densitometry source holder, a calibration jig. The sealed source and the device are evaluated together because the real-world radiation safety of a source depends on the shielding, shutters, interlocks, and mechanical integrity of the thing it lives in.²

The regulatory logic is straightforward: rather than have every end user independently prove that a given source-in-device is safe, the NRC (or an Agreement State) evaluates the design once, documents the acceptable conditions of use on a registration certificate, and makes that certificate available so that reviewers and users can rely on it. The end user then simply references the registered item and agrees to use it within the certificate's conditions.¹² This is the same "evaluate once, rely many times" philosophy that underlies much of materials licensing; see our overview of the NRC materials license process.

Topic Explanation

What SS&D registration is

SS&D registration is the process by which the NRC or an Agreement State reviews the radiation-safety information for a sealed source or device and issues a registration certificate that is incorporated into the National Sealed Source and Device Registry (NSSDR). The regulation that establishes the NRC's safety-evaluation and registration criteria is 10 CFR 32.210, which clarifies the responsibilities of registration certificate holders for products the NRC evaluates and registers.¹

The guidance that tells a manufacturer how to apply, and tells a reviewer how to evaluate, is NUREG-1556, Volume 3, "Applications for Sealed Source and Device Evaluation and Registration," Revision 2, published in September 2015. It covers the applicable regulations and industry standards, the general policies and procedures affecting evaluation and registration, how and where to file a request, the review process, and how to draft and modify a registration certificate.²

Who registers, and who uses

A critical point that confuses new RSOs: the end-user facility usually does not apply for SS&D registration. The manufacturer or initial distributor of the source or device obtains the registration. The user then:

references the registered source or device by manufacturer and model number on its own specific license application, as contemplated by 10 CFR 30.32 for license applications; or
possesses certain low-risk devices under a general license in 10 CFR Part 31 (for example, specified measuring, gauging, or controlling devices), with limited requirements.³⁴

Either way, the user inherits the conditions on the SS&D certificate and must operate within them. The registry and certificate are the bridge between what the manufacturer proved and what the user is permitted to do.

Key Technical Principles

What the SS&D certificate contains

The SS&D certificate (often called the SS&D sheet or registration sheet) is a compact technical document. It typically specifies:²

the source or device model and the manufacturer/distributor;
the radionuclide(s) and the maximum activity;
the prototype testing and the source classification (temperature, external pressure, impact, vibration, and puncture performance, following consensus standards such as ISO 2919);
the conditions of normal use and the intended applications;
the leak-test method and interval required for the source;
labeling and marking requirements; and
limits on who may install, service, or dismantle the source or device.

The classification matters physically: a source rated for higher temperature and impact can be used in harsher environments, and the certificate's conditions reflect what the prototype actually survived.²⁶

Registered vs custom, and the exemptions

Not every sealed source needs an individual registration. 10 CFR 32.210 includes exceptions — for example, certain calibration and reference sources below stated activity thresholds (on the order of 37 MBq, or 1 mCi, for beta/gamma emitters) are handled differently.¹ The table below summarizes how a facility typically ends up using a registered source or device.

Pathway	Regulatory basis	Typical examples	User's core obligations
Generally licensed device	10 CFR Part 31 (e.g., 31.5)	certain fixed gauges, some measuring/controlling devices	register the device where required, follow label conditions, leak test and report per the general license
Specifically licensed source/device	10 CFR 30.32 referencing the registered SS&D	blood/research irradiators, brachytherapy and calibration sources, bone-densitometry sources	reference the correct model, stay within SS&D conditions, leak test, inventory, secure
Exempt calibration/reference source	10 CFR 32.210 exceptions	low-activity check sources below the stated threshold	handle per license; registration requirements may not attach

Worked example: interpreting a leak test

The SS&D certificate sets the leak-test interval; the regulations set the pass/fail limit. Under NRC medical-use rules a sealed source is considered to be leaking if a wipe test shows removable contamination at or above 185 Bq (0.005 µCi).⁵ Converting a counter reading to removable activity is a routine RSO calculation. If a wipe is counted at net count rate $C_{net}$ (counts per minute) with a detector efficiency $ε$ (counts per disintegration), the removable activity in becquerels is

A_{removable} = \frac{C _{net}}{ε \times 60}

where the factor of 60 converts disintegrations per minute to disintegrations per second (Bq). For a wipe reading of $C_{net} = 300$ cpm on a system with $ε = 0.15$ counts per disintegration:

A_{removable} = \frac{300}{0.15 \times 60} = \frac{300}{9} \approx 33 Bq

Because 33 Bq is well below the 185 Bq limit, the source passes. Had the same reading come from a far less efficient geometry — say $ε = 0.02$ — the computed removable activity would be $300/ (0.02 \times 60) = 250$ Bq, which exceeds the limit and would require removing the source from service. The lesson is that the leak-test result is only meaningful when the counting efficiency is known and documented, which is why leak-test analysis ties directly into the facility's sealed source leak-testing program and counting-efficiency records.

Clinical Impact

Why SS&D registration protects patients and staff

The SS&D certificate is the quiet backbone of safe sealed-source use. Its conditions are what keep the source's shielding, shutter mechanism, and encapsulation performing as evaluated. A few practical consequences:

Servicing limits prevent breach. The certificate restricts who may open or service a device. A facility that lets an untrained technician dismantle a device can defeat the engineered safety the registration relied on.
Leak-test cadence catches failures early. The interval on the certificate (commonly every six months for many medical sealed sources, with exceptions for low-activity, gas, or low-energy beta sources) is set so that a degrading capsule is caught before it spreads contamination.²⁵
Correct model references keep the license defensible. Referencing the wrong manufacturer or model on a license — or using a source in a device it was never registered for — undermines the whole safety basis and is a common inspection finding.

These controls feed the facility's broader source-security and accountability program, including inventory, sealed source inventory and accountability, and, for risk-significant quantities, nationally tracked source reporting.

Self-shielded irradiators and other high-activity devices

High-activity devices such as self-contained blood or research irradiators are a clear case where the device registration carries real safety weight: the Cs-137 or X-ray source sits behind heavy shielding and interlocks that the SS&D evaluation examined. Facilities operating these units should understand the certificate conditions in the context of our guide to self-contained irradiator radiation safety.

Practical Optimization Tips

Keep an SS&D file for every source and device. Maintain the current SS&D certificate, the manufacturer/model numbers, the classification, and the required leak-test interval for each item, cross-referenced to your license.
Verify the license reference matches the hardware. Before an inspection, confirm that each source/device on site matches a model referenced on your license and a current registry entry.³
Respect the servicing restrictions. Do not perform maintenance the certificate reserves to the manufacturer or an authorized service provider; doing so can void the registration basis.
Document leak-test efficiency. Record the counting geometry and efficiency used to convert cpm to removable activity, so a passing or failing result is defensible.⁵
Confirm the authority for Agreement State registrations. A source registered by one Agreement State is generally recognized elsewhere, but naturally occurring and accelerator-produced material (NARM/NORM) and some products follow host-state rules — verify before relying on a registration.²
Plan for end of life. Track decay and the eventual disposition of each source; a device whose source has decayed below usefulness still contains licensed material that must be transferred or disposed of properly.

Regulatory Considerations

SS&D registration sits at the manufacturer–regulator interface, but its conditions flow straight through to the user's license and radiation-protection program. The core frameworks are:

10 CFR 32.210 — establishes the NRC safety-evaluation and registration criteria and the responsibilities of registration certificate holders; the certificate is incorporated into the NSSDR.¹
NUREG-1556, Volume 3, Revision 2 (2015) — the consolidated guidance for SS&D evaluation and registration applications and certificates.²
10 CFR Part 31 — general licenses for certain devices containing byproduct material, with their registration and reporting requirements.⁴
10 CFR 30.32 — license application content, including identification of registered sources and devices by manufacturer and model.³
10 CFR 35.67 (and parallel provisions) — leak-testing and the 185 Bq (0.005 µCi) removable-activity criterion for sealed sources in medical use, and related possession controls.⁵
10 CFR Part 20 — the dose limits, surveys, and ALARA program that frame all of this.⁷
Consensus standards — ISO 2919 and related standards define the source classification tests referenced in the registration.⁶

Agreement States administer compatible SS&D programs. Of the states DRPS serves, Florida, Maryland, Virginia, California, Nevada, Pennsylvania, New York, and New Jersey are NRC Agreement States that evaluate and register sources and devices under their own compatible rules, while Washington DC and Delaware are regulated directly by the NRC for radioactive material. The NSSDR is maintained jointly so that a registration issued by one authority can be relied on by others; always confirm the current registry entry and your license conditions. For the surrounding compliance picture, see common radiation safety violations and how to avoid them.

Frequently Asked Questions (FAQs)

What is SS&D registration?

SS&D registration is the NRC or Agreement State process of evaluating the radiation-safety design of a sealed source or device and issuing a registration certificate (the SS&D sheet). The certificate is entered into the National Sealed Source and Device Registry and defines the conditions for safe use.¹²

Does the facility that uses a sealed source apply for SS&D registration?

Usually no. The manufacturer or initial distributor obtains the registration. A user references the registered source or device by manufacturer and model on its own specific license, or possesses certain devices under a general license, and must stay within the certificate conditions.³⁴

What does an SS&D certificate specify?

It identifies the source or device, the radionuclide and maximum activity, the prototype test results and classification, the conditions of normal use, the leak-test method and interval, labeling, and any servicing limits. Operating outside those conditions can void the registration basis.²

What is the leak-test removable-activity limit for a sealed source?

Under NRC rules a sealed source is generally considered to be leaking if the wipe shows removable contamination at or above 185 Bq (0.005 µCi). A source at or above that limit must be removed from service and handled per the license and regulations.⁵

What is the difference between a generally licensed and specifically licensed device?

Certain low-risk measuring and gauging devices containing registered sealed sources may be possessed under a general license in 10 CFR Part 31 with limited requirements. Higher-risk sources and medical or research uses require a specific license under which the registered SS&D is referenced and additional controls apply.³⁴

Who supports SS&D compliance at a facility?

The RSO, supported by a qualified or board-certified medical physicist, confirms that each source and device is registered, that use stays within the certificate, that leak tests and inventories are current, and that license records reference the correct manufacturer and model numbers.

Key Takeaways

SS&D registration evaluates the sealed source and its device together and issues a certificate entered into the National Sealed Source and Device Registry.¹²
The manufacturer registers; the user references the registered item by model number on a specific license or possesses it under a general license.³⁴
The SS&D certificate sets the radionuclide and activity, classification, conditions of use, leak-test interval, and servicing limits — all binding on the user.²
A sealed source is generally considered leaking at removable contamination ≥ 185 Bq (0.005 µCi); interpreting the wipe requires a documented counting efficiency.⁵
Certain calibration/reference sources below about 37 MBq (1 mCi) are handled under exceptions in 10 CFR 32.210.¹
Agreement States run compatible programs and share the NSSDR; confirm the registry entry and license conditions, especially for NARM/NORM.²

Conclusion

SS&D registration is the mechanism that lets a facility trust a sealed source without re-proving its safety from scratch. The certificate on file for each source and device is a condensed record of what the design survived in testing and how it must be used, maintained, and leak-tested to keep that safety intact. For an RSO and medical physicist, the work is disciplined but simple: keep every certificate current, make sure the hardware on site matches the models on the license and in the registry, leak test on schedule with a documented efficiency, and never let anyone service a device in a way the certificate does not allow. Do that, and the engineered safety the registration evaluated keeps working for the life of the source.

How DRPS Can Help

Diagnostic Radiation Physics Services (DRPS) supports sealed-source programs with radioactive material license support, SS&D and inventory review, leak-test and counting-efficiency program setup, and radiation safety officer support aligned with NRC and Agreement State requirements.

DRPS serves facilities across Florida, Maryland, Virginia, Washington DC, California, Nevada, Pennsylvania, New York, New Jersey, and Delaware.

Related Resources

References

U.S. Nuclear Regulatory Commission. 10 CFR 32.210: Registration of product information. nrc.gov
U.S. Nuclear Regulatory Commission. Consolidated Guidance About Materials Licenses: Applications for Sealed Source and Device Evaluation and Registration. NUREG-1556, Volume 3, Revision 2. September 2015. nrc.gov
U.S. Nuclear Regulatory Commission. 10 CFR 30.32: Application for specific licenses. nrc.gov
U.S. Nuclear Regulatory Commission. 10 CFR Part 31: General Domestic Licenses for Byproduct Material. nrc.gov
U.S. Nuclear Regulatory Commission. 10 CFR 35.67: Requirements for possession of sealed sources and brachytherapy sources (leak testing). nrc.gov
International Organization for Standardization. ISO 2919: Radiological protection — Sealed radioactive sources — General requirements and classification. iso.org
U.S. Nuclear Regulatory Commission. 10 CFR Part 20: Standards for Protection Against Radiation. nrc.gov
U.S. Nuclear Regulatory Commission. Sealed Sources and Devices Toolkit. nrc.gov