ML20149M127

Submits Article from Energy Daily Re Concerns Over Activities at Maine Yankee

ML20149M127
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Site:	Maine Yankee
Issue date:	11/21/1996
From:	Blanch P AFFILIATION NOT ASSIGNED
To:	NRC
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NUDOCS 9612120306
Download: ML20149M127 (3)

Text

-

From:

PAUL M. 8LANCH <PMBLANCH91x.netcom.com>

To:

WND2.WNP3(jaz,awd),WNDl.WNP2(hjm),TWDI.TWP4(gam,wj...

l Date:

11/21/96 8:02am l

Subject:

MAINE UCS

-A0 UCS, NRC At Odds Over Maine Yankee, Again Source: THE ENERGY DAILY i

THE ENERGY DAILY via Individual Inc. : The Union of Concerned -

Scientists is urging the Nuclear Regulatory Commission to shut down the troubled Maine =

l Yankee nuclear plant immediately, and not allow the reactor to resume operation until a - number of critical scfety problems are resolved at the Bath, Maine, reactor.

UCS' drive to shut down the plant is being spearheaded by the - group's new nuclear expert, David Lochbaum, who released an assessment Tuesday of a recent - major NRC investigation at Maine Yankee. And while Lochbaum and NRC largely agree on what = the reactor's technical problems are, they clearly differ on the safety - implications of those problems.

In its inspection report, which was released last month, the NRC - team concluded that while the reactor cannot be safely operated at full power, 910 megawatts, -

adequate safety margins l

exist to operate the plar.t at the current level of 825 MW. Maine -

Yankee had been operating at 910 MW for nearly 18 years; however, commission staff in January =

ordered Maine Yankee

[

to reduce its output to 825 MW after allegations of degraded safety - at the reactor first l

i surfaced.

Lochbaum disagrees with NRC's conclusions. He maintains that the - reactor is unsafe to operate--at either power level--and is an accident waiting to = happen.

I

NRC must take immediate action to correct these problems if the = people in Maine are to be protected from safety risks,' Lochbaun, a veteran nuclear - engineer, said in releasing his i

findings.

Lochbau.n's concerns center around the ability of certain emergency - safety systems--including the reactor's emergency diesel generator and - component cooling water i

systems--to respond as they are designed to at current opsrating - levels.

i Lochbaum maintains 9612120306 961210 PDR ORG NRRA PDR l

l l

that-these systems each challenge safe operation of Maine Yankee, = even at its presently authorized power level.'

i He points out that the NRC team identified several weaknesses and = non-l conservative judgments in Maine Yankee's calculation for emergency diesel = generator

• loading. ' A loading calculation confirms that the generating capacity of the = emergency generator exceeds the total power eequirements of the electrical equipment it =

supplies. In Maine Yankee's case, NRC found that there is a relatively small margin--a =

difference of just.28 i

percent-- between these two figures.

1 In addition, the team noted that Maine Yankee's loading calculation = does not take into account ambient air temperatures above 90 degrees Fahrenheit = following a l

design basis l

accident. According to Lochbaum, when that temperature is exceeded, =

cooling limitations are placed on the emergency generator, which in turn would require a - derating in its electric output.

And, he continued, [s]ince the... loading calculation provides = merely.28 percent margin for

)

l derating the [ generator's] electrical output, it is not apparent = that the l

[ generator] can supply l

all the required loads under design bases conditions even at the = present authorized power l

l evel. "

A similar problem exists for the plant's component cooling water = systems, he said. These systems remove decay heat and heat generated by emergency equipment =

following a reactor accident. According to Lochbaum, NRC's calculations for these = systems showed essentially no margin at the prasently authorized power level." The NRC team - also emphas~ized that the system could not be relied on to operate at full power.

Finally, Lochbaum said, regardless of whether the plant can be = safely operated at 825 MW, NRC should fine Maine Yankee significantly for operating the plant - for i

nearly 18 years at power levels it was not equipped to handle in accident conditions.

I uTHE ENERGY DAILY -- 11-21-96>>

[11-20-96 at 18:01 EST, Copyright 1996, King Publishing Group]

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l Paul M. Blanch Energy Consultant 135 Hyde Rd.

West Hartford CT 06117 l

. Voice 860-236-0326 Fax 860-232-9350 t

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