A bit of digression. Many ideas for product or safety improvement may not reach the decision-makers. Suggestions being made here, and many others, may have been thought of and proposed, but died on the way to the decision makers.

I was thinking about the structure of the average corporation.
There often is a disjunct between the objectives at the decision levels in the hierarchy. From the top:

CEO and Board
These men usually habe proven ability to maximize shareholder shareholder profit and expansion. They may have little detailed knowledge of the company's products, whether widgets or resources.

Heads of Operations
These men may have risen from the technical ladder, but most often are from the business management divisions- marketing, finance.
Their decisions are based on the upper level's need (shareholder profit and expansion) although they depend on the chiefs of the divisions producing the product or resource.

Divisional Operations
These groups have the technical manpower with the expertise to develop and improve the product, or to find and exploit the resource.
Although they are the basis of the company, they are not concerned with the marketing, presentation, politics of the product or resource. Usually there is a group that considers the safety of product and employees and makes recommendations for improvement.

A division at the base may have a good idea, which they present to their management heads. It may be accepted and presented to the next level, or it may be shelved- budget, set-up expense, price, outside the scope of a directive from on high, etc.

Heads of operations organize and present the product, resource development or safety provisions to the Board and CEO, whose decisions are based on marketability, economy of operation, fit to shareholders needs, politics, etc.

The technical employees at the bottom thus often see an idea, product or safety recommendation die or be shelved, never reaching the top of the hierarchy.

Some companies try to establish good communications among the levels but some are rigid and comunication is discouraged or punished. TEPCO may have been a member of the latter group.