SNRC-2188, Responds to NRC Request for Addl Info Re Certain Elevated Levels Found During Phase 4 Confirmatory Survey

Responds to NRC Request for Addl Info Re Certain Elevated Levels Found During Phase 4 Confirmatory Survey

ML20078A109
Person / Time
Site:	Shoreham File:Long Island Lighting Company icon.png
Issue date:	01/20/1995
From:	Petschauer F LONG ISLAND POWER AUTHORITY
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LSNRC-2188, NUDOCS 9501240284
Download: ML20078A109 (7)

Text

w c-Long Shorshim Nucitar Power Station Island P.O. Box 628 Power North Country Road Authority Wading River, N.Y.11792 ,

l JAN2 01995 LSNRC 2188 U.S. Nuclear Regulatory Commission Document Control Desk Washington, D.C. 20555 t

Shoreham Decommissioning Project LIPA Response to NRC Request for AdditionalInformation Related to Elevated Levels Found During Phase 4 Confirmatory Survey ,

Shoreham Nuclear Power Station - Unit 1 l Docket No. 50-322  !

i Ref: (1) Telephone Conversation between S. Baggett, D. Fauver, R. Nimitz and L. Pittiglio of NRC, and F. Petschauer, C. Newson and S. Kumar of LIPA on January 9,1995.  ;

i Ladies and Gentlemen:  :

This letter presents the response of the Long Island Power Authority (LIPA) to the request for additionalinformation made by the NRC concerning certain elevated levels found during the Phase 4 Confirmatory Survey. LIPA agreed to provide a formal response and discussion during the telephone cc nversation referenced above.

During the confirmatory surveys performed by the Oak Ridge institute for Science and Education (ORISE) Team for the NRC during the week of October 31,1994, nine '

elevated fixed point beta-gam.ma measurements were noted by the ORISE team in the Dryer / Separator Storage Pool, Survey Unit RB072, and the Spent Fuel Storage Pool, Survey Unit RB068. The elevated fixed point measurements identified by the ORISE '

team in the Dryer / Separator Storage Pool were within the guideline values of Regulatory Guide 1.86. Based on subsequent LIPA surveys, two'of the elevated measurement locations identified by the ORISE team in the Spent Fuel Storage Pool were found to be slightly above the guideline values of Regulatory Guide 1.86. In 210024 j 9501240284 9D0120 PDR ADOCK 05000322 00k g

P PDR 1 j

LSNRC-2188 Page 2 of 3 keeping with the principle of ALARA, all locations identified by the ORISE team were remediated by LIPA although only two locations in the Spent Fuel Storage Pool exceeded the Regulatory Guide 1.86 guidelines. An "as left" survey was performed by the ORISE team to insure that the levels were well below established guideline values. At the exit meeting on November 4,1994, the ORISE team leader stated that the final survey of the remediated locations were acceptable and below the established guideline values.

In an effort to examine why the ORISE team was able to find the highly localized elevated readings in the Spent Fuel Storage Pool during the confirmatory survey (and LIPA was not), the numerous support and termination survey activities of these and similar survey units were reviewed by LIPA. LIPA was unable to establish the cause with any degree of certainty. LIPA concluded that it would be highly speculative to pinpoint any one activity, survey instrument, or a particular individual for the missed measurement.

The area surveyed in the Dryer / Separator Storage Pool and the Spent Fuel Storage Pool were estimated to be about 3,720,000 cm2 and 6,020,000 cm2 respectively.

Moreover, taking into account only the affected areas of the Shoreham facility, the total area surveyed was about 320,000,000 cm 2. Of this the areas of elevated levels exceeding the guideline values of Regulatory Guide 1.86 were confined to about 25 cm 2, a very small fraction (0.0000001) of the total area surveyed.

Subsequent to the NRC/ORISE exit meeting on Friday, November 4,1994, the NRC Project Inspector requested the plant staff to perform a follow-up survey of the remediated locations in the Dryer / Separator Storage Pool and the Spent Fuel Storage Pool to confirm that the elevated levels were not caused by any type of " weeping".

Pursuant to this request, a follow-up survey of the Dryer / Separator Storage Pool and the Spent Fuel Storage Pool was conducted on Wednesday, November 9,1994, one week following the remediation. The survey included the nine remediated locations and an additional five random measurement locations in each survey unit.

The results of the follow-up survey in the Dryer / Separator Storage Pool indicated a mean value of 140 DPM/100 cm2 based on 316 measurements. This was slightly lower than the mean value of 144 DPM/100 cm2found after remediation based on the same number of measurements. The additional five random measurements taken during the follow-up survey were found to'be consistent with the original data collected.

LSNRC-2188 Page 3 of 3 The results of the follow-up survey in the Spent Fuel Storage Poolindicated a mean i value of 302 DPM/100 cm2 based on 430 measurements. This was equal to the mean value after remediation based on the same number of measurements. The additional five random measurements taken during the follow-up survey were also found to be consistent with the original data collected.

The above results lead to the conclusion that there is no indication of weeping in the Shoreham Dryer / Separator Storage Pool and the Spent Fuel Storage Pool.

Furthermore, the elevated levels noted by the ORISE team were extremely localized. ,

When weeping was identified by other licensees in the past, it was typically much more widespread and uniform, and resulted in smearable contamination over large areas exposed to the same usage. The highly localized nature of the few elevated levels observed at Shoreham and the lack of any smearable contamination also tend to eliminate weeping as a possible explanation.

Enclosures 1 and 2 provide summaries of the surveys performed. These were '

previously transmitted to the NRC Project inspector on November 15,1994.

If you have any questions or need further information, please do not hesitate to contact me.

Very truly yours, Jc HE Frederick Petschauer Resident Manager

Enclosures:

(1) Diyer/ Separator Storage Pool, Survey Unit RB072 (2) Spent Fuel Storage Pool, Survey Unit RB068 cc: R. Bernero, Director '

Office of Nuclear Materials Safety and Safeguards L. Bell C. L. Pittiglio T. T. Martin R. Nimitz ,

D. Fauver

~

ENCLOSURE 1 DRYER / SEPARATOR STORAGE POOL, SURVEY UNIT RB072 The final termination survey was completed on this survey unit in mid September 1994. Based on the usage history of this survey unit it was classified as an AFFECTED survey unit. The survey design required 100% gridding, a complete scan of the structure with fixed point and smears taken in every other grid block with corresponding exposure rate measurements where accessible. The results of the 314 fixed point and smear measurements and the 294 exposure rate measurements taken, as reported in the final report, were below the guideline values established for this survey unit and are consistent with similar surveys.

During the ORISE confirmatory survey of this survey unit on November 1,1994 four locations were found to be elevated, but below the established guideline values for fixed point measurements. Termination Survey personnel performed a before and after remediation survey of each location.

On November 2,1994 the ORISE team resurveyed the remediated locations with acceptable results.

On November 9,1994, as requested, Termination Survey personnel surveyed the four locations and an additional five locations within the survey unit. The results are consistent with the after remediation survey performed on November 1,1994. The measurements from the additional five locations surveyed are also consistent with previous measurements of the area and there is no evidence of " weeping" taking place in this survey unit.

The attached data sheet documents the final survey results.

4 RB072 - DRYERISEPARATOR STORAGE POOL AFTER REMEDIATION AND RESURVEY AND + 1 V1EEK MEASUREMENTS BEFORE AFTER +1 WEEK AREA GCPM DPMI >Lc GCPM DPMI >Lc GCPM DPMI >Lc 100CM2 +HTDN 100CM2 +HTDN 100CM2 +HTDN F12

• 181 531 174 388 185 612 F33 358 4143 10772 181 531 152 -81 F43 178 469 179 490 183 571 WO9

• 669 10490 27274 244 1816 4722 228 1490 3874 F18

• 122 -873 F32* 162 143 l F37 130 -510 W10 139 592 W164 119 184

-INCLUDED IN ORIGINAL DATA ORIGINAL DATA REPORT - MEAN OF 135 DPMI100CM2 FOR 314 MEAS.

WITH NEW DATA - MEAN OF 144 DPMI100CM2 FOR 316 MEAS.

+1 WEEK DATA - MEAN OF 140 DPMI100CM2 FOR 316 MEAS.

+1 WEEK DATA - MEAN OF 133 DPMI100CM2 FOR 319 MEAS. (ADDT'L MEASUREMENTS)

(BEFORE REMEDIATION - MEAN OF 258 DPMI100CM2 FOR 316 MEAS.)

NOTE - FOR THIS UNIT TO INCLUDE THE HTDN'S:

THE AVERAGE GUIDELINE VALUE IS 11100 DPMI100CM2 THE MAXIMUM INDIVIDUAL MEAS. GUIDELINE IS 33300 DPMI100CM2 P. .CASSIDY 11111/94

ENCLOSURE 2 SPENT FUEL STORAGE POOL, SURVEY UNIT RB068 The final termination survey was completed on this survey unit in the first week of September 1994. Based on the usage history of this survey unit it was classified as an AFFECTED survey unit. The survey design required 100% gridding, a complete scan of the structure with fixed point and smears taken in every other grid block with exposure rate measurements. The results of the 428 fixed point, smear measurements and exposure rate measurements taken, as reported in the final report, were below the guideline values established for this survey unit and are consistent with similar surveys.

l

During the ORISE confirmatory survey of this survey unit on November 2,1994 five locations were found to have elevated fixed point measurements. Three of these measurements were below the established guideline values. Termination Survey personnel performed a before and after remediation survey of each location.

On November 3,1994 the ORISE team resurveyed the remediated locations with l I

acceptable results.

On November 9,1994, as requested, Termination Survey personnel surveyed the five locations and an additional five locations within the survey unit. The results are consistent with the after remediation survey performed on November 2,1994. The measurements from the additional five locations surveyed are also consistent with previous measurements of the area and there is no evidence of " weeping" taking place in this survey unit.

l The attached data sheet documents the final survey results.

l I

1 l

e l

_- - _ _ _ - _ ____-_________a

3 RB068 - SPENT FUEL STORAGE POOL AFTER REMEDIATION AND RESURVEY AND + 1 WEEK MEASUREMENTS BEFORE AFTER + 1 week AREA GCPM DPM/ >Lc GCPM DPM/ >Lc GCPM DPM/ >Lc 100CM2 +HTDN 100CM2 +HTDN 100CM2 +HTDN F12

• 961 16980 39054 138 184 143 286 F60

• 449 6531 15021 155 531 1221 173 898 2065 W429

• 305 3980 9154 117 143 133 469 W430 1030 18778 43185 205 1939 4460 172 1265 2910 W432 247 2796 6431 104 -122 120 204 F84 163 694 1596 F54 116 -265 F24

• 123 -122 W16 98 -245 W242 110 0

-INCLUDED IN ORIGINAL SURVEY ORIGINAL DATA REPORT - MEAN OF 289 DPM/100CM2 FOR 428 MEAS.

WITH NEW DATA - MEAN OF 302 DPM/100CM2 FOR 430 MEAS.

• 1 WEEK DATA - MEAN OF 302 DPM/100CM2 FOR 430 MEAS.

+ 1 WEEK DATA - MEAN OF 301 DPM/100CM2 FOR 434 MEAS. (ADDT*L MEASUREMENTS)

(BEFORE REMEDIATION - MEAN OF 561 DPM/100CM2 FOR 430 MEAS.)

NOTE - FOR THIS UNIT TO INCLUDE THE HTON'S:

THE AVERAGE GUIDELINE VALUE IS 9400 DPM/100CM2 THE MAqMUM INDMDUAL MEAS. GUIDELINE IS 28200 DPM/100CM2 GM.CASSIDY P. R 11/11/94

- _ _ _ _ - . - _ _ - _