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EXHIBIT 068 · INFRASTRUCTURE

Three Mile Island: the interface obscured the system

Equipment malfunction, design-related problems, and operator actions contributed to a partial reactor meltdown.

OrganizationMetropolitan Edison / TMI
Period1979
LocationUnited States
StatusInvestigated
ImpactCritical
EvidencePrimary documentation
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Illustrative draft · Source-backed synopsis · Museum analysis marked separately · Updated 5 October 2026

Three Mile Island Nuclear Generating Station in Pennsylvania, the site of the 1979 Unit 2 accident.
Three Mile Island Nuclear Generating Station in Pennsylvania, the site of the 1979 Unit 2 accident.United States Department of Energy / Wikimedia Commons. Resized. Photograph · Context photograph; not the incident itself. · Public domain · Resized for display.
01 / EXECUTIVE SUMMARY

The outcome is only the beginning.

Equipment malfunction, design-related problems, and operator actions contributed to a partial reactor meltdown. [1]

THE PRINCIPLE TO CARRY FORWARD

Show physical system state directly where possible and train teams on misleading indications and evolving failure scenarios.

02 / THE PROMISE

What the system was trying to do.

Generate electricity through a controlled nuclear process.

Museum interpretation

The assumption beneath the promise

Museum hypothesis to examine: People will infer the true physical state and automation mode from the information available under stress. This is an analytical proposition to test against the record, not an attributed statement by the organization.

Success should be assessed against the intended service and its safety, reliability, or integrity constraints. A headline outcome cannot tell us whether those constraints were visible, tested, or owned before the event.

03 / WHAT HAPPENED

A sequence, not a single moment.

The intended system

Generate electricity through a controlled nuclear process.

Source-backed synopsis

The event or review

Equipment malfunction, design-related problems, and operator actions contributed to a partial reactor meltdown. [1]

Source-backed synopsis

The documented aftermath

NRC changes addressed training, emergency planning, and control-room design. [1]

Source-backed synopsis
Timeline of documented milestones. Gaps are not evidence that nothing happened. Sources: [1]
04 / WARNING SIGNS

What could be seen at the time?

Documented in cited record

Operators had difficulty understanding the plant’s actual state from available indications. [1]

Who could see it?

See the cited investigation for named teams and the information they held. The synopsis does not infer awareness by every stakeholder.

Why was it not enough?

Signals need interpretation, authority, and a route to action. This is an analytical question, not proof that a warning was deliberately ignored.

05 / KEY DECISIONS

Choices made within constraints.

Museum analysis: Control-room design and training needed to support diagnosis of ambiguous failures.

Available alternatives

Pause, test, narrow the operating envelope, seek independent review, or build a recovery option. These are proposed analytical alternatives; feasibility at the time is not established.

Information available

Operators had difficulty understanding the plant’s actual state from available indications. [1]

Incentives & constraints

Delivery pressure, cost, authority, and incomplete knowledge may shape a decision. Their specific weight is not established by this synopsis.

Risk accepted

Ask whether the relevant risk was recognized, who had authority to accept it, and whether affected people understood its implications.

06 / SYSTEM MAP

How conditions connected.

Select a node to inspect its evidence. Links show a proposed analytical relationship, not a measured causal effect.

05 / External context04 / Warning signal03 / Decisions02 / Technical conditions01 / Trigger06 / Consequences
Triggering event

Equipment malfunction, design-related problems, and operator actions contributed to a partial reactor meltdown. [1]

Legend: numbered nodes = analytical categories; dashed arrows = proposed influence or propagation. Museum interpretation informed by the sources below. Feedback and omitted influences require further investigation.
07 / CONSEQUENCES

Beyond the immediate event.

The accident damaged the reactor and transformed public confidence and nuclear oversight. [1]

Technical impactOperational impactHuman impact

Categories identify documented or relevant consequences. Financial, human, and environmental totals are not estimated here when the source base does not support them.

08 / WHAT THE MODELS EXPLAIN

More than one lens.

Analytical lens

Swiss Cheese Model

Harm can pass through gaps in multiple defenses: organizational influences, supervision, preconditions, and active failures.

In this case, use the lens to examine human-system interaction. This application is museum interpretation, not a finding of the original investigation.

Limit: A useful lens, not proof of a universal linear cause. Barriers interact and change over time.

Analytical lens

FMEA

Identify failure modes, their effects, and controls before or during system development.

In this case, use the lens to examine human-system interaction. This application is museum interpretation, not a finding of the original investigation.

Limit: Lists can miss interactions and unanticipated operating conditions; scores are not exact probabilities.

Analytical lens

Systems thinking

Examine relationships, boundaries, feedback, and incentives across a whole system.

In this case, use the lens to examine human-system interaction. This application is museum interpretation, not a finding of the original investigation.

Limit: A broad lens needs explicit boundaries and evidence to avoid explaining everything after the fact.

09 / COUNTERFACTUALS

What could have changed the outcome?

Counterfactuals are hypotheses. They identify possible intervention points without claiming that a different choice would certainly have prevented the event.

INTERVENTION 2 / During early testing

Test the operating envelope

Exercise realistic boundary conditions and shared dependencies rather than validating components only in isolation.

Cost & feasibility

Requires time and independent review before commitment.

Likely effectiveness

May reduce exposure or consequences. Not quantified; feasibility and effect must be assessed against evidence available at the time.

10 / LESSONS

From hindsight to a usable practice.

FOR FOUNDERS

Show physical system state directly where possible and train teams on misleading indications and evolving failure scenarios.

Before accelerating hiring or spending, name the assumptions that remain untested and set evidence thresholds for the next commitment.

11 / AFTERWARD

Recovery is another investigation.

NRC changes addressed training, emergency planning, and control-room design. [1]

A corrective action is evidence of a response; it is not, by itself, evidence that the wider pattern has disappeared.

12 / SOURCES & EVIDENCE

Follow the record.

Documented claims are linked to sources. Analytical applications, lessons, and intervention proposals are museum interpretation. This draft does not establish motives or a single complete causal explanation.

  1. 1
    nrc.gov — Metropolitan Edison / TMI case record

    Primary documentation · Accessed 4 October 2026

Editorial history & limits

Version 1 · 4 October 2026 — source-backed illustrative synopsis created. Independent editorial review is pending. No claim of exhaustive investigation. New sources may alter the analysis.