physics

HDPE piping in nuclear power plant systems

HDPE piping in nuclear power plant systems is a physics topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand HDPE piping in nuclear power plant systems rather than just read about it. In short: Piping systems in U.S. nuclear power plants that are relied on for the safe shutdown of the plant (i.e. “safety-related”) are typically constructed to Section III of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (B&PV) Code. The materials allowed by the ASME B&PV Code have been historically limited to metallic materials only.

Key takeaways

HDPE piping in nuclear power plant systems belongs to physics; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect HDPE piping in nuclear power plant systems to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of HDPE piping in nuclear power plant systems from memory before moving on to harder problems.

Reference excerpt

Piping systems in U.S. nuclear power plants that are relied on for the safe shutdown of the plant (i.e. “safety-related”) are typically constructed to Section III of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (B&PV) Code. The materials allowed by the ASME B&PV Code have been historically limited to metallic materials only. Due to the success of high density polyethylene (HDPE) in other industries, nuclear power plants in the U.S. have expressed interest in using HDPE piping in ASME B&PV Code applications. In 2008, the first U.S. nuclear power plant was approved by the United States Nuclear Regulatory Commission (U.S. NRC) to install HDPE in an ASME B&PV Code safety-related system. Since then, the rules for using HDPE have been integrated into the 2015 Edition and 2017 Edition of the ASME B&PV Code. The NRC approved of the 2015 and 2017 Editions in 2020.

History 1963 – Section III of the ASME B&PV Code created and only allows metallic materials. 2007 – Code Case N-755 issued on behalf of Duke Energy for the use of Polyethylene Plastic Pipe for Class 3 piping applications. Code Case N-755 limits HDPE fusing to butt fusion. 2008 – U.S. NRC grants Callaway Plant, Unit 1, permission to use HDPE in the Essential Service Water System based on Code Case N-755 and additional plant specific information. 2009 – U.S. NRC grants Catawba Nuclear Station, Units 1 and 2, permission to use HDPE in the Nuclear Service Water System based on Code Case N-755 and additional plant specific information. 2010 – First Revision to Code Case N-755 issued. 2013 – Second Revision to Code Case N-755 issued. 2014 – U.S. NRC rejects Code Case N-755-0 (Revision 0) for generic use due to unresolved issues concerning the joining procedure, degradation processes, and examination of joints. 2015 – U.S. NRC grants Edwin I. Hatch Nuclear Plant, Unit 2, permission to use HDPE in the Plant Service Water System. 2015 –The use of Polyethylene Plastic Pipe for Class 3 applications is incorporated into Mandatory Appendix XXVI of ASME Section III. 2017 – U.S. NRC rejects Code Case N-755-1 for generic use due to ongoing unresolved issues. 2020 - U.S. NRC approves 2015 Edition of ASME B&PV Code which includes the use of HDPE piping for Class 3 applications.

ASME boiler & pressure vessel code sections for HDPE ASME B&PV Code Section III – Rules for Construction of Nuclear Facility Components

Appendix XXVI – Rules for Construction of Class 3 Buried Polyethylene Pressure Piping Article XXVI-1000: General Requirements Article XXVI-2000: Materials Article XXVI-3000: Design Article XXVI-4000: Fabrication and Installation Article XXVI-5000: Examination Article XXVI-6000: Testing Article XXVI-7000: Overpressure Protection Article XXVI-8000: Nameplates, Stamping, and Reports Article XXVI-9000: Glossary Mandatory Supplements I – III Non-mandatory Supplements A - D ASME B&PV Code Section IX – Welding, Brazing, and Fusing Qualifications

Part QF – Plastic Fusing Article XXI – Plastic Fusing General Requirements Article XXII – Fusing Procedure Qualifications

Application The use of HDPE in U.S. nuclear power plants is currently limited to PE4710 material since this was the material first identified in Code Case N-755 and approved by the U.S. NRC. Code Case N-755 and the 2015 Edition of ASME B&PV Code, Section III, Appendix XXVI are limited to butt fusion (i.e. hot plate welding) only. Electrofusion is included in the 2017 Edition of the ASME B&PV Code, Section III, Appendix XXVI. Both N-755 and Appendix XXVI limit the use of HDPE to Class 3 piping systems.

Required examination and testing All welds made with either hot plate welding or electrofusion welding are required to be visually inspected and have a hydrostatic pressure test. All joints in pipe 4 inches and large must have 100% volumetric non-destructive examination (NDE) performed. The volumetric NDE may be either ultrasonic examination or microwave examination.

Benefits The steel piping used in service water systems at nuclear power plants are often subjected to various forms of degradation including general corrosion, microbiological induced corrosion, tuberculation, and galvanic corrosion. HDPE is typically impervious to these forms of degradation. Additionally, nuclear power plants typically have robust seismic requirements and HDPE is very flexible which increases its ability to survive an earthquake.

Challenges The use of HDPE in nuclear power plants requires extensive qualification and testing efforts to demonstrate that the material is safe under all design basis conditions. The U.S. NRC has raised concerns in the past with the use of HDPE related to butt fusion joint integrity, the ability to detect flaws in joints, and the potential for slow crack growth. This has prevented the NRC from generically approving the use of HDPE. Nuclear Power plants can still request approval from the U.S. NRC on a case-by-case basis (i.e., relief request).

Current status of U.S. NRC approval The NRC has reviewed the 2015 and 2017 Editions of the ASME B&PV Code which have been accepted and incorporation into 10CFR50.55a with the following conditions related to the use of HDPE:

References

Illustrations

Worked examples

Example 1 — a first encounter with HDPE piping in nuclear power plant systems

Start with the simplest possible case. Write down what HDPE piping in nuclear power plant systems claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In physics, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to HDPE piping in nuclear power plant systems before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about HDPE piping in nuclear power plant systems ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of HDPE piping in nuclear power plant systems

In research: HDPE piping in nuclear power plant systems appears in physics research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses HDPE piping in nuclear power plant systems in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: HDPE piping in nuclear power plant systems is common in secondary-school and first-year university syllabi. It links to neighbouring topics Nuclear power stations, Plastics applications, so understanding it makes those chapters shorter.
In everyday life: Look for HDPE piping in nuclear power plant systems outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study HDPE piping in nuclear power plant systems in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what HDPE piping in nuclear power plant systems means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain HDPE piping in nuclear power plant systems out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is HDPE piping in nuclear power plant systems in simple terms?

Why does HDPE piping in nuclear power plant systems matter?

Because it connects several physics ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study HDPE piping in nuclear power plant systems?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on HDPE piping in nuclear power plant systems.