10/3/2013

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Require Thinning Spent Fuel Pool

and

Safer Dry Cask Storage

Presentation by Mary Lampert

Pilgrim Watch

A Wake-Up Call: Fukushima, Unit 4

Pilgrim &Fukushima- Same Design

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What is Spent Nuclear Fuel?

• Pilgrim generates electricity with 580 nuclear fuel

assemblies in the reactor’s core

• Assemblies = bundles of fuel rods & each rod

contains many Uranium 235 fuel pellets

• Spent (or used) nuclear fuel is no longer efficient for

making electricity- its fission process slowed down

• Spent fuel is moved from the reactor core to the

spent fuel pool

• It is highly radioactive & thermally very hot

Pilgrim’s Spent Fuel Pool

What’s The Problem?

• Location: Upper floor of reactor, outside primary

containment, thin vulnerable roof overhead

• Crowded: Designed to temporarily store 880 spent

fuel assemblies. Now contains 3,279; allowed to

hold 3,880

• Fire: If water lost (just to height of assemblies) →

fire → radia,on releases

• Consequences: Up to $488 billion in damages,

24,000 latent cancers, contaminate > 100 miles

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Location Pilgrim’s Spent Fuel PoolThin Roof Overhead - Outside Primary Containment

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What Could Cause a Pool Fire?

1. Security

• Attackers: means, motive and opportunity.

• Shoulder-mounted assault weapon (the modern Bazooka) launched off-site.

• Explosive laden small aircraft

• Defenses: no defense to those threats - defenses limited

2. Electric Power

• Safety systems are dependent on electricity to cool, maintain and makeup water in spent fuel pool

• Electric power is not assured, and there is insufficient back-up

• (2) diesel generators + (1) backup generator, oil for 7 days

• Battery backups able provide power for additional 8 hrs

3. Instrumentation

• Now, no pool instrumentation to measure water level & temp

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Pool Fire Threat (continued)

4. Crowded Pool: The pool often contains short-cooled fuel, which increases the fire hazard.

fuel exposed 100 days after discharge from the reactor could heat to the point of self-ignition in about 4 hours. Fire then would spread to older fuel

5. Reactor Accident →Pool Fire: Following a reactor core melt, radiation fields etc. could preclude personnel from the access needed to prevent a pool fire

6. Pool Fire →Reactor Accident: Reactor safety systems are threatened by (1) water from pool leakage, and (2) from water sprayed into the pool to put out fire that then overflows on to reactor safety systems

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How to Reduce Risk?

Dry Cask Storage

• Reduce risk by re-equipping pools with low-density, open-frame racks

• Fuel cooled > 5 years out of reactor can and should be moved into dry casks

• Casks are passive - no mechanical functions or human intervention needed

• Casks cost about $1.5 million each

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Dry Casks

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Pilgrim’s Dry Casks: Holtec Hi-Storm 100

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Spent Fuel Storage

Entergy’s Plan vs. Safer Plan

Entergy’s Pool – Keep the pool densely packed

• Remove only enough assemblies from the pool to dry casks to make room in the pool for those removed from the core every two years (3-4 casks)

• Leave a dangerous high-density/ closed frame pool

Safer Plan- Thin-out The Pool

• Place all assemblies in the pool > 5 years out of reactor in dry casks

• Leave a safer, open frame, low density pool

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Security: Pilgrim’s Plan

“Candlepin Bowling for Terrorists”

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Dry Cask Storage - SecuritySafer Plan vs. Entergy’s Plan

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Safer Plan: Disperse Casks – Mound Earth Berms

To Protect Against line-of-sight Attack

Security: Fallback Safer Solution

Blast Shields

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Dry Cask Storage – MonitoringEntergy’s Plan vs. Safer Plan

Problem: Dry casks prematurely degrading from moisture, especially in marine environments→ need for enhanced monitoring and adequate drainage

Entergy’s Plan

– Monitors not required by NRC- no plan install them

Safer Plan:

– Install monitors to measure temperature and radiation releases

– Establish protocol for notifying State and local communities

– Require Entergy to provide funding to State and local community for oversight required

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Dry Cask Storage – Air VentilationEntergy’s Plan vs. Safer Plan

Entergy’s Plan

– Mitigation is necessary to prevent blockage (such as an overhead roof), but nothing is required. Entergy no plan for roof over casks

Safer Plan

– Casks have air holes at bottom and top of casks

– If the holes are blocked by ice, debris, or bird nests cooling will not occur

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What if Casks degrade or need

replacement?

Entergy’s Plan

None announced

Safer Plan

–Keep its spent fuel pool

–Have spare over-packs on site, or at a

regional site so the spare over-pack

can be delivered within 5-6 hours

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Flooding

Entergy’s Plan vs. Safer Plan

Problem

• NRC says fuel casks may stay onsite up to 300 years

• Storage pad close to shore

• Climate change ↑ flooding risk- storm surge, high waves on top surge – worst case scenario, happening at high tide. Sea level rise exacerbates problem.

Entergy’s Plan

• Locate pad 100 yards from Cape Cod Bay, at an elevation of 25’ above sea level.

Safer Plan

• Locate dry casks farther away from Cape Cod Bay and at a higher elevation to avoid flooding

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Emergency PlanningAfter Electric Generation Ends

Problem• Technically, the NRC is supposed keep emergency

planning until spent fuel pool is gone

• But, NRC grants exemptions - Kewaunee NPS allowed stop offsite planning (1 and ½ years) after closure

• Risk: One typical cask would contain about 1/2 the total amount of cesium-137 released during the Chernobyl reactor accident of 1986

Entergy’s Plan: not announced

Safer Plan: Keep Emergency Planning so long as spent fuel is stored onsite.

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Dry Cask Storage RecapSafer Way

• Low-Density/Open-Frame: Remove all assemblies in the pool > 5 years out of reactor to dry casks

• Security: disperse the casks and place berms around them – as a fallback install blast shields

• Mitigation: prevent blockage of air ventilation

• Monitoring: install monitors to measure heat and radiation

• Spare over-packs: stored onsite or close-by

• Flooding: locate casks to avoid flooding

• Emergency Planning, offsite: Until fuel is moved offsite

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How long will America’s Hometown

be a Nuclear Waste “Dump?”

• The highly toxic, long-lived spent fuel will be here until there is a national off-site repository & Pilgrim gets its turn on the shipping schedule

• NRC says it could be a long time

• NRC ‘s new draft waste policy allows– 60 years in the spent fuel pool

– 100 years in dry casks

– Every 100 years - new casks and storage pad

Will Entergy be around to be responsible and to pay the bills?

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