U.S. NUCLEAR REGULATORY COMMISSION

Region III Office of Public Affairs

801 Warrenville Road, Lisle IL 60532-4351

NEWS ANNOUNCEMENT: RIII-96-36 July 3, 1996

CONTACT: Jan Strasma 708/829-9663

Angela Dauginas 708/829-9662

E-mail: opa3@nrc.gov

NRC ISSUES AUGMENTED INSPECTION TEAM REPORT

ON HYDROGEN GAS BURN IN SPENT FUEL CASK AT POINT BEACH PLANT

The Nuclear Regulatory Commission Augmented Inspection Team

has issued its report on the hydrogen gas burn which occurred May

28 in a spent fuel storage cask at the Point Beach Nuclear Power

Station.

An exit meeting with the utility, open to the public, was

held June 7 at the Two Creeks Town Hall to present the

preliminary findings of the team. The report's conclusions are

consistent with those presented at the June 7 meeting.

Among the principal findings of the team's report are:

-- There was no evidence of damage to the spent fuel as a

result of the gas burn and no measurable releases of

radioactivity as a result of the gas burn.

-- The source of the hydrogen was a chemical reaction between a

zinc-based coating and the borated water from the spent fuel

storage pool.

-- Opportunities were missed to identify the potential

generation of hydrogen during the initial design, design

review, and design specifications for the spent fuel cask.

-- The utility had several opportunities to identify the

production of hydrogen during previous cask loading

activities when abnormalities were noted. These

abnormalities were not documented and were not thoroughly

evaluated.

The Augmented Inspection Team's function was to gather

information rather than determine compliance with NRC

requirements. The team's findings will be reviewed during

subsequent NRC inspections to assess the utility's regulatory

compliance.

The executive summary of the AIT report is attached. Copies

for the 29-page report are available from the Region III Office
of Public Affairs upon request.

#####

NRC AUGMENTED INSPECTION TEAM REPORT - EXECUTIVE SUMMARY

On May 28, 1996, after loading a VSC-24 ventilated storage cask

with spent fuel, an unanticipated hydrogen gas ignition occurred

inside the cask during welding of the shield lid. The gas

ignition, which was heard by plant technicians, displaced the

shield lid in the upward direction approximately 3 inches, and

cocked it at a slight angle. The shield lid is approximately 9

inches thick, 5 feet in diameter, and weighs slightly less then

6,400 pounds.

There was no evidence of damage to the spent fuel in the cask as

a result of the gaseous ignition. The Augmented Inspection Team

(AIT) concluded that there were no offsite radiological

consequences as a result of this event. During this event, all

possible station release pathways to the public were monitored

with no indication of abnormal releases. The AIT further

concluded that there were no measurable releases of radioactivity

from the cask and no unanticipated radiation exposures to the

staff. There were no personnel injuries.

The licensee's actions during and following the event including

management oversight were good. However, the inspectors

identified several weaknesses in unloading procedures, safety

evaluations, corrective actions and rigging practices.

The licensee has concluded and the AIT agrees, that the source of

the hydrogen was an electrochemical reaction of zinc in the Carbo

Zinc 11 coating when in contact with the borated water in the

spent fuel pool (SFP). The coating is used to prevent corrosion

of the multi-assembly sealed basket (MSB). At the conclusion of

the AIT inspection the licensee had not fully completed their

root cause investigation. However, the licensee believes that

opportunities were missed to identify that the electrochemical

reaction of the coating with borated water would result in the

generation of hydrogen. Those opportunities occurred during the

initial design, design review and design specification for the

VSC-24 cask.

In addition, the AIT concluded that the licensee had several

opportunities to identify the generation of gas inside of the MSB

during previous cask loading operations due to several noted

abnormalities. However, the abnormalities were not documented,

were not thoroughly evaluated, and were not viewed collectively.

This is of particular concern because the licensee had direct

indications that combustible gas was being produced.

The AIT determined that the potential generic implications of the

event extend beyond the use of the VSC-24 system. Consideration
should be given to reviewing the adequacy of the chemical

compatibility evaluations conducted during design reviews for all

dry cask storage designs. Consideration should also be given to

determining the suitability of Carbo Zinc 11 and other similar

coatings used in nuclear applications, where there is the

potential to expose them to boric acid.

####