Watts Bar – Making History In Yet Another Century

Jeanne Dion
Project Manager
Watts Bar Special Projects Branch
 

Unit 1 at the Watts Bar Nuclear Plant in Spring City, Tenn., has a claim to fame as the last U.S. commercial nuclear reactor to come online in the 20th century. Now, the Tennessee Valley Authority aspires to have its sister reactor (Watts Bar Unit 2) make its own historic claim.

Numerous cranes helped complete construction of the Watts Bar Nuclear Plant Unit 1 containment building in front of the plant’s cooling towers in 1977.
Numerous cranes helped complete construction of the Watts Bar Nuclear Plant Unit 1 containment building in front of the plant’s cooling towers in 1977.

If the NRC concludes that the reactor is safe to operate and approves its operating license next year, Watts Bar Unit 2 could become the first new commercial nuclear reactor to come online in the U.S. in the 21st century.

To understand a little of the history of Watts Bar Nuclear Plant, let’s rewind to a time when Schoolhouse Rock premiered and the first mobile phone call was made in New York City — a time predating the NRC. In 1973, the Atomic Energy Commission greenlighted construction of Watts Bar Units 1 and 2 under the “two-step licensing process,” where construction permits and operating licenses were issued separately.

In 1985, construction quality issues at its plants caused TVA to stop work at both Watts Bar Units. Eventually, TVA resolved the issues and completed construction of Unit 1, and the NRC issued its operating license in 1996.

Fast-forward to more recent activities. TVA decided in 2007 to reboot the Watts Bar Unit 2 construction and licensing process. They submitted an update to their original license application to the NRC in 2009.

Other recent applicants have elected to use the combined license application process, where we issue a single license to both construct and operate a nuclear power plant at a specific site. However, because of the unique history of Watts Bar Unit 2, TVA chose to continue under the two-step licensing process. So, NRC staff developed a regulatory framework and established a licensing approach tailored specifically to the project.

We updated our construction inspection program associated with the two-step licensing process to provide guidance that reflects current NRC practices. For example, the NRC staff identified areas for further inspection at Unit 2 by screening applicable communications, allegations and other open items in the review.

The NRC staff also developed inspection guidance specific to TVA’s refurbishment program, which replaces or refurbishes systems and components at Watts Bar Unit 2. TVA’s resolution of key safety issues and the continued progress of construction inspection activities drive our review schedule.

If the operating license is issued next year, the NRC’s job doesn’t just end. We’d continue to inspect start-up testing required for power ascension and to oversee that Unit 2 transitions into the NRC’s Reactor Oversight Process before it can begin producing commercial power.

And, of course, the Resident Inspectors, the agency’s eyes and ears at the plant, would continue to carry out day-to-day inspection work to ensure safety and security is monitored and inspected during licensing and throughout the transition to commercial operation.

For more information about the Watts Bar Unit 2 project, visit the NRC’s website. There will be a Commission briefing Oct. 30 at 9 a.m. on the license application review. You get details about the briefing from the meeting notice. We’ll also do a live webcast.

Part II: Ensuring Safety in the First Temple of the Atom

Thomas Wellock
NRC Historian
 

https://www.lib.ncsu.edu/specialcollections/digital/text/engineAs noted in Part I of this story on the NC State research reactor, the Atomic Energy Commission (AEC) was very anxious to promote the world’s first civilian reactor. But its enthusiasm was tempered by the challenge of placing a reactor safely on a busy college campus and developing an approval process for non-AEC reactors.

The AEC turned to its Reactor Safeguard Committee, the forerunner of today’s Advisory Committee on Reactor Safeguards. The Committee was formed in 1947 to evaluate the safety of new reactors proposed by AEC laboratories and contractors.  “The committee was about as popular—and also necessary—as a traffic cop,” recalled Safeguard Committee Chairman Edward Teller.

The Committee’s most significant contribution was establishing a conservative approach to safety given the engineering uncertainty of that era. “We could not follow the usual method of trial and error,” Teller said. “The trials had to be on paper because the actual errors could be catastrophic.” The Committee developed a “simple procedure” of challenging a reactor designer to write a “hazard summary report” that imagined the worst “plausible mishap”—soon known as a “maximum credible accident”—and demonstrate the reactor design could prevent or mitigate it.

Five NC Stte physics professors designed the reactor. Here, in the reactor control room (left to right front row) are Clifford K. Beck and Arthur C. Menius, Jr. Standing is Newton Underwood, three unidentified students, Arthur Waltner and Raymond L. Murray.
Five NC State physics professors designed the reactor. Here, in the reactor control room, (left to right front row) are Clifford K. Beck and Arthur C. Menius, Jr. Standing is Newton Underwood, three unidentified students, Arthur Waltner and Raymond L. Murray.

The Committee focused on several hazards, including a surge in the chain reaction called a reactor “runaway,” a catastrophic release of radioactive material from fire, sabotage, or an earthquake, and hazards from routine operation that might result from leaks or inadvertent exposures. The Committee asked NC State to address these concerns in a “hazards summary report.”

To meet the Committee’s desire for inherent safety, NC State proposed a “water boiler” reactor, which was believed to have “student-proof” safety margin given its strongly “negative coefficient” of reactivity that limited greatly the possibility of a runaway. NC State also developed interlocks and an extremely dense concrete shielding to discouraged sabotage.

In order for NC State to commit the funds to such a long-term project, it needed an early approval. This created a dilemma since the college did not yet have a detailed, complete design.  The AEC used a two-step conditional approval that was similar to its later construction permit/operating license process. In step one, construction did not begin until NC State addressed the most important design safety issues. When it did, the AEC agreed by contract to supply enriched fuel. The fuel was not delivered, however, until NC State resolved all outstanding safety questions and a final inspection took place. With that, the first civilian reactor in history went critical in September 1953.

The AEC approach to safety at NC State foreshadowed many later regulatory practices. As important as the 1954 Atomic Energy Act is to current regulatory practice, it is interesting to see that many of the critical elements have even deeper roots back toward the beginning of the atomic era.

 

Throwback Thursday — Atoms for Peace

hpAtoms for Peace BusWhich U.S. president launched this program – Atoms for Peace? The program’s intent was to share nuclear technology and isotopes with American allies while maintaining control of weapons-grade material. It also supplied equipment and information to schools, hospitals and research institutions within the U.S. (Photo by Ed Westcott/DOE)

 

Throwback Thursday — Kennedy’s Nuclear Visit

hpDr_Alvin_Sen_KennedyBefore John F. Kennedy became president, he was elected to the U.S. House of Representatives and the U.S. Senate. During his time on Capitol Hill, he visited the Oak Ridge National Laboratory in Tennessee. Here, he’s photographed with ORNL Director Alvin Weinberg. Can you guess the year this photo was taken and who accompanied the then-Senator Kennedy? Extra points if you know what nuclear technology Weinberg is credited with spearheading. (Photo taken by Ed Westcott/DOE)

 

Throw Back Thursday – The Cyclotron

HP60-Inch%20CyclotronThe 60-inch cyclotron (circa August 1938) was an enormous machine for its day. It used a magnet weighing 220 tons (shown here). Dr. Ernest Lawrence would later build a 184-inch cyclotron and go on to win the Nobel Prize in what year? Extra points if you can name the man at the top with a pipe in his mouth.