* Companies say closed-loop cooling, new reactor could cut

water use to near zero

* Valar demonstrates its microreactor powering Nvidia's ( NVDA )

Blackwell chip architecture in Utah

* Poll shows voters are concerned about water, power demands

of data centers

By Valerie Volcovici and Timothy Gardner

July 1 (Reuters) - Valar Atomics, a nuclear power startup,

said on Wednesday it is partnering with Nvidia ( NVDA ) to

develop a small data center in Utah that the companies claim

will show how computing facilities needed for AI can conserve

water.

California-based Valar announced the partnership in Utah at

the site of its small nuclear plant called a microreactor. It

also ran a demonstration powering Nvidia's ( NVDA ) Blackwell, its latest

AI chip architecture for data centers. It was the first time a

small reactor powered a data center, the companies said.

Valar is one of about 10 nuclear energy startups in a

Department of Energy reactor pilot program that set a goal to

demonstrate three small reactors reaching criticality - when a

nuclear reaction can sustain itself - by July 4.

Nvidia ( NVDA ) announced last week that it would use closed-loop

liquid cooling for DSX, its latest data center design, a method

it says can reduce facility-cooling water consumption from

roughly 2.6 million gallons per megawatt per year to near zero.

DATA CENTER OPPOSITION GROWS

Concerns over U.S. data centers' demand for power and water have

led to a backlash.

A Reuters/Ipsos poll last month showed that only one in

three Americans approve of the fast ​pace of data center

construction, an issue on the minds of ​voters ahead of the

November 3 midterm elections.

The industry's power need has led companies to seek to

source their own power with private or "behind-the-meter" plants

to enable them to bypass permitting, public stakeholder

engagement and grid interconnection.

These projects have primarily been natural gas, but some

companies are eying nascent small nuclear reactors to power AI

infrastructure.

WHITE HOUSE PUSHES REACTORS

President Donald Trump's administration sees small nuclear

reactors as one of several ways to expand power generation.

Trump last May issued executive orders aimed at quadrupling

nuclear deployment.

"Through this work with Valar Atomics, Nvidia ( NVDA ) is exploring

how behind-the-meter, waterless advanced nuclear systems could

support future AI factories built for the scale and reliability

accelerated computing requires," said John Josephakis, an Nvidia ( NVDA )

global vice president.

Valar founder Isaiah Taylor said the startup is attempting

to demonstrate that nuclear projects, which often face long

regulatory hurdles, can be done quickly. Valar says its

high-temperature reactor is cooled with helium instead of

water.

Valar joined litigation against the Nuclear Regulatory

Commission last year by the states of Texas and Utah arguing

that it does not have licensing authority over some nuclear

microreactors and small modular reactors, seeking to give that

oversight to individual states.