ML20210L049

Partially Deleted Request for FOIA Documents Re Source of High Alarms Generated by Radiation Effluent Detector or Detectors in Discharge Canal at Big Rock Point on 980314,15 & 25.Partially Deleted Info Encl

ML20210L049
Person / Time
Site:	Big Rock Point File:Consumers Energy icon.png
Issue date:	06/30/1999
From:	Drey K AFFILIATION NOT ASSIGNED
To:	NRC OFFICE OF ADMINISTRATION (ADM)
Shared Package
ML20210L038	List: ML20210L032 ML20210L049
References
FOIA-99-282 NUDOCS 9908090026
Download: ML20210L049 (8)

Text

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WW Mrs. Leo Drey gg 4

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g et June 30, 1999 FOIA/ Privacy Act Officer F0IA/LPOR Branch U.S. Nuclear Regulatory Commission Mail Stop T-6 D8 Washington, DC 20555-0001

-- a Freedom of Information Act request --

Dear Sir or Madam:

This letter is a request for information under the Freedom of Information Act, as amended.

I have been trying, through phone calls to the NRC starting in May 1998 and letters starting in October 1998, to obtain specific information on the source of the high alarms generated by a radiation effluent detector or detectors in the Discharge Canal at the Big Rock Point nuclear power plant at Charlevoix, Michigan, on Lake Michigan (Docket No. 50-155).

The incidents occurred on March 14, 15, and 25, 1998, and perhaps at other times. Although I have received responses from the NRC, I still do not know the concentration levels or isotopic contents of the contaminants.

(As you know, this small [69 or 72-MWe] boiling water reactor operated from November 1965 until August 1997.)

I am interested in learning the isotonic content and contamination levels and the estimated volume of the gray-brown algae that allegedly caused the alarms.

A chronological accounting follows of the information I have received:

1. According to the NRC Operations Center's " Daily Events Report" for Event Notification 33901 of March 15, 1998:

The licensee completed sampling and analysis of the service water inlet and concluded that the source of the activity was from sediments in Lake Michigan containing radioactive material from previous discharges.

I

[ emphasis added]

2. According to NRC Inspection Report #98-02, dated February 3 - April 6, 1998, at page 21:

Preliminary results of the investigation indicated that the elevated discharge canal monitor readings were not the results of radioactivity in discharges from the plant but were either contaminated algae or sediment that had been concentrated in the canal by high winds.

(identified as followup Item 50-155/98002-04(DNMS).

[ emphasis added]

3. According to NRC Inspection Report #98-03, dated April 7 - May 27,1998, at page 9:

9908090026 990803 PDR FOIA DREY99-282 PDR

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With the plant in decommissioning status, the canal discharge liquid effluent radiation monitor alarmed.

The alarm was confirmed to be accurate by taki.ng samples which indicated that for a liquid release the canal effluent was at the maximum oermissible Co-60 Icobalt-6M i

concentration.

The radioactivity in the discharge canal was found to be borne by oerichyton faray-brown alaae) which had concentrated at the screenhouse due to prevailing weather conditions. During the 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> prior to the alarm, winds were directly from the north at an average speed of 25 miles per hour. Waves in excess of five feet scoured accumulated l

periphyton from the rocks and suspended the organisms in the water. The

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weather conditions, combined with no circulating water flow to take the canal discharge to the lake as the circulating water pumps were off, allowed for the accumulation of the periphyton. Subsequently, the periphyton became dislodged and was brought into the plant water intake through the discharge weir and the recirculation warming line.

This recycled the periphyton between the plant water intake and the j

discharge, resulting in elevated levels of radioactivity being indicated j

in the plant discharge canal. After the wind shifted direction and the licensee started a circulating water pump for dilution the condition cleared.

)

Sediment samples collected in the discharge, along with sample.s collected by divers between the screenhouse and intake structure indicated normal activity levels consistent with past environmental data. This indicated that the algae was the carrier of the radioac-tivity and that it was introduced into the intake through the warming line causing the canal radiation monitor to alarm. Corrective actions were to ensure that circulating water pumps are on for all liquid batch releases and to revise Emergency Procedure EPIP-1 to remove the i

J requirement for the declaration of an unusual event at twice maximum oermissible concentration. which is below the reoortina limits. This inspection followup item is closed.

[ emphases added]

4. According to a November 4, 1998, letter I received from Jan Strasma, Senior Public Affairs Officer, NRC Region III:

Upon investigation, the elevated measurements were attributed to gray-brown algae which had accumulated low levels of radioactivity, principally cobalt-60. High winds and waves scoured the algae from the rocks and drove them into the intake and discharge canals, which are interconnected. The algae apparently accumulated on a screen surrounding the radiation monitor in sufficient concentration to trigger the monitor. Since the plant is no longer operating, there was no circulating water flow into the lake to move the algae away from the canals and dilute their effect.

Analysis of lake water and lake sediment at that time does not show any detectable radioactivity associated with the Big Rock Point plant. Ihg cobalt-60 aooarently was concentrated in the alaae. The radiation monitor alarm resulted from the lake conditions at that time combined

/

.3 with the shutdown status of the plant which led to the accumulation of the algae.

[emphasesadded)

5. And finally, according to a May 10, 1999, letter from Mr. Strasma:

We have no further data or documents on the issue beyond what I sent you previously -- i.e., the sections from the two inspection reports, 98-02 and 98-03. The INRCl insoector reviewed Consumers Enerav Company data durina the course of the inspection. but we do not have a coov of that dalA.

In your followup letters, you had requested the isotopic content and estimated volume of the contaminated gray-brown algae that were associated with the elevated measurements. We do not have that data.

There was no release of radioactivity from the plant associated with the elevated measurements. Rather, the elevated measurements were caused by an accumulation of algae, containing low levels of radioactivity, that had been dislodged by heavy weather conditions combined with the lack of circulating water flow to take the canal discharge to the lake since the plant is shut down. As part of its investigation of the situation, the utility collected sediment samples which showed normal levels which were I

consistent with that observed in previous environmental monitoring.

[ emphases added]

Apparently the NRC inspector had reviewed the licensee's data about the concentration of cobalt-60 in the algae, but failed to keep those data.

I would like to know what the levels of Co-60 were that the inspector apparently concurred were " low."

I would also be interested in learning what radioiso-topes other than Co-60 were also analyzed in the algae and sediment samples, and with what results.

Perhaps the radiochemical analyses of the algae would be considered propri-etary knowledge, but if not, I would appreciate a copy of the licensee's data.

And if the sediment data are also not proprietary, I would appreciate that information, as well.

Security number is 6 I was born in 6 0n 3 1 will be happy to pay for photocopying and postage.

Your response will be greatly appreciated.

Sincerely,

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Jul-22-99 12:47P US. Nuclear Reg. Comm. BRP 616 Ei47 - 4 086 P.02

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Conenmers Energy Memorandum To:

Operations Department Personnel -

From:

TAGoble

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Date!

9 September 1998

Subject:

Canal Liquid Process Monitor Alarms cc:

KPPowers KEPallagi TAG 98-03 RAEnglish TDPetroskey CNBarsy

. This memo is written to address the cause of the recent Discharge Canal Liquid Prc alarms. Three occurrences of the Canal LPM alarm during rain storms were logged on 23 and September 1,1998. Isotopic analysis of canal dip samples from each of these any radioactivity of plant origin. Several isotopic analyses ofsamples taken during the most r event showed that the activity is naturally occurring Pb-214 and Bi-214 which are decay products Radon-222. %e most plausible explanation for this activity is atmospheric deposition of airborne particles that are washed into the storm drain system and then to the canal, Additional contribu these alarms are (1) the previous alarm set point of 190 cpm above background which is only Technical Specification limit, and (2) loss of the motive force from the circulating water pump had kept fresh intake water moving out the discharge.

In response to these events the Canal Liquid Process Monitor alarm set point has been raised f cpm to 1150 cpm above background. He Technical Specification limit is 1500-1900 cpm above backgroun depeuding on the release scenario. The new alarm set point should climinate nuis resulting fmn naturally occurring isotopes while still being sufficiently below the TS limit to allow alarm drift (* 30%) and also for appropriate response time if the alarm is received.

In March of this year, we had two other Canal LPM alarm episodes, one of which also caused th Water monitor alarm. The cause for these events was not the same as those of the past mont March alarms the cause was increased activity detected in algae due to recent high act cross flow through the partially open warming line and lack ofcirculating water flow. This root ca was substantiated through isotopic analysis showing radioactivity of plant origin (Co-60, Mn.5 Cs-137). During investigation of these earlier events, radioactivity of plant origin was also dete sediment from the east-side storm drain system caused by algae contamination of service water discharged to the drain via seal water from the water box vacuum pumps. Rose storm drains w cleaned out the week of September 14 as a final corrective action to the March events.

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