Thursday, November 12, 2015

A Reasonable Look at Emergency Planning for Vermont Yankee: Guest post by Howard Shaffer

A Draft Plan

Shaffer speaking in favor of VY
PSB hearing, November 2012
Vermont's Nuclear Decommissioning Citizen's Advisory Panel (NDCAP) has written a draft plant for future emergency planning in the area around Vermont Yankee.  You can read the plan here, or I can summarize it. (This summary is simply my opinion.)

The mountains may crumble, Gibraltar may tumble, but Entergy providing money for emergency planning for the towns around Vermont Yankee---that money must be here to stay.

Howard Shaffer wrote a very reasonable comment on the plan, which I am happy to post as a guest post.  You can read more about NDCAP in the notes at the bottom of this post.

Shaffer Comments on the Draft Plan

Comments on the
Draft Advisory Opinion on
Continued Funding for the Radiological Response Plan
by the 
Vermont Nuclear Decommissioning Citizens Advisory Panel


The Emergency plan’s purpose is to provide for public safety during the decommissioning period.  This draft of a discussion to justify continued funding of a plan outside the plant fence appears to have been influenced by emotional concerns about the Emergency Plan used during the now completed operational period.  This draft has not sufficiently focused on the radical difference in the potential hazard that occurs after the energy releasing chain reaction in the fuel ceases.

While the plant is in operation and fission is on-going, fission products are continually produced.  After the plant is no longer operating, fission products are no longer produced, and the existing fission products decay.  The nature of any radioactive decay is that it continually decreases with time. The change from operating to not-operating is not reflected well in this draft plan.

The draft should take into account the continual decrease in the potential hazard, and the implications of the continual decrease of energy release.  The slowing of the energy release means that the any hazard from a  release of radioactive material from any damaged fuel pellets would take longer and longer to develop as time goes by, after the plant has ceased operation. The time also allows for intervening action by responders to interrupt and contain the release.

The draft seems to focus only on protective action outside the plant boundary, and forgets that inside the boundary there will always be a plan, and there would be protective and intervening action inside the boundary.

The Nuclear Regulatory Commission’s approach takes into account both the continually decreasing potential hazard and the continually increasing length of time available for intervening action by responders.  The Commission’s approach recognizes that an Emergency Response Plan will always be needed, but for a smaller and smaller area.   The area of concern that might be affected by any release shrinks with time until it is all inside the plant boundary.

The draft does not seem to recognize the shrinkage when it contemplates a plan outside the boundary until there is no radioactive material on site.  The draft uses a potential public exposure limit that is so low that it unrealistic.  No number for the avoided exposure is given.

Problems in the Draft

The draft states that “Nevertheless, all drained structures, systems and components across the entire site are contaminated with layers of solid radioactive material …”  All?  That will be news to the employees who worked in the offices, warehouses, and operated and maintained the many secondary plant systems and equipment. Many systems and parts of the plant are not contaminated.  For example the systems handling river water, electric power, and diesels etc.  Understanding which things are contaminated and which are not is fundamental to a safe and economical decommissioning.

The draft is concerned with “radiation exposure” to the public as it should be, but does not seem clear on the fact that what this means is “excess radiation exposure.”  That is, exposure that can be controlled or avoided in excess of the natural amount of exposure everyone gets.  The draft refers to the State of Vermont’s limit of 25 mrem per year. This limit is exceeded in the State House, in the corners, by the radiation coming from the granite blocks.  Locally we all get 28 mrem per year at 0-1000 feet above sea level from cosmic radiation (Denver = 52 mrem per year).  We all get on average another 200 mrem per year from Radon gas in the air. Medical diagnostic procedures account for some exposure (CT Abdominal scan 800 mrem; I had two in 90 days).  The draft should be clear on what exposures might be if there is an accident releasing radioactive material any time during decommissioning.

The draft should have considered the physical sources of the potential radioactive material.  The main source is the used fuel pellets.  These pencil eraser sized ceramic pellets are in sealed metal tubes.  The tubes make up fuel bundles and the bundles will eventually all be in the sealed metal cans, inside the concrete shield chimneys, which are the outer layer of the Dry Cask assemblies. If an accident occurred that resulted in some fuel pellets being scattered on the ground, they would continue to be air cooled, and remain solid. Unlike, say, coal ash, these pellets are highly sintered ceramic. They would probably break into shards, not dissolve into dust.  All the structure of the plant and its equipment are a much smaller source of hazard.

While used fuel remains in the Fuel Pool in the reactor building there is some slight risk that loss of pool water could eventually lead to a release, due to used fuel damage from overheating and possible fire.  Water loss is not likely. The Fuel Pool has a heavy stainless steel liner designed and tested for zero leakage.  It is set in the middle of the Reactor Building, surrounded on the sides and bottom by thick reinforced concrete walls and floors. The top of the pool is open to the Refueling Floor, but there are many feet of water above the used fuel.  The refueling floor is surrounded by the heavy steel beams that support the overhead crane and roof.  This structure and the crane would break an aircraft impacting the building.  The pool has no drain line, and attached lines have siphon breakers.  There are several sources of water for normal and emergency filling.

Opponents of the plant cite it as being a GE Mark I style, as are the plants at the Fukushima- Daiichi site. Those pools survived the earthquake of 2011.  The unit 4 building had no fuel in the reactor, and much fuel in the fuel pool.   After being hit by the tsunami, the Unit 4 building settled several inches and tilted a little. The used and new fuel in that pool stayed in the pool, was never uncovered, and has now all been safely removed.  This demonstrates the robustness of the pool and building.


This draft  has two serious problems: lack of numerical values for expected off-site emissions, which could be compared to regulatory limits, and lack of understanding of the process of radioactive decay: radioactive materials get less radioactive as time goes by.  However, it is a start on a document that could be used in the decision making process.

Howard Shaffer  PE (nuclear) VT, NH, MA, IL
November 11, 2015


The Citizen's Advisory Panel and the Draft Emergency Plan

When Vermont Yankee closed down, Vermont dissolved its Vermont State Nuclear Advisory Board VSNAP.  This panel's meetings (IMHO) had become room rentals for people to get together and bash Vermont Yankee.

When the plant announced it would close, Vermont started convened a new panel, the Nuclear Decommissioning Citizen's Advisory Panel, NDCAP.  The new panel includes members from New Hampshire and Massachusetts, and members from Vermont Yankee and the IBEW.  In terms of membership, NDCAP is clearly a more representative group than the old VSNAP. You can read its membership list here.

Howard Shaffer

Howard Shaffer has attended almost every meeting of this panel.  He acknowledges that he was late in submitting his comment on the draft plan: he missed a deadline for commenting.  That means his comments may not get into the Department of Public Service public record.

His comments are now in the public record, right here at this blog.

Shaffer has contributed many guest posts to this blog. One of my favorite posts is Where's the Magic Switch, about power and pricing on the grid. Howard Shaffer and I both received Presidential Citations from the American Nuclear Society in 2012. Photo below courtesy of American Nuclear Society.

Howard Shaffer, Meredith Angwin,
ANS president Eric Loewen

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