ML20049J405

Technical Evaluation of Response to Attachment 2 of Item II.F.1 of NUREG-0737,Addl Accident Monitoring Instrumentation.

ML20049J405
Person / Time
Site:	Pilgrim
Issue date:	03/01/1982
From:	Huchton R SIEMENS POWER CORP. (FORMERLY SIEMENS NUCLEAR POWER
To:	NRC
Shared Package
ML20049J403	List: ML20049J405
References
RTR-NUREG-0737, RTR-NUREG-737, TASK-2.F.1, TASK-TM NUDOCS 8203180115
Download: ML20049J405 (4)

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TECHfilCAL EVALUATION OF THE RESPONSE TO ATTACHMEf4T 2 0F ITEM II.F.1 0F NUREG-0737

" ADDITIONAL ACCIDENT-MONITORIfiG IftSTRUMENTATION" FOR THE PILGRIM NUCLEAR P0'AER STATION UNIT 1 (Docket No. 50-293)'

BY R. L. HUCHTON EXXON Nuclear Idaho Company, Inc.

P. O. Ecx 2800 Idaho Falls. Idaho 83401 8203180115 820301

• DRADOCKOS000g Q

REFERENCES

, -l II.F.1-2 Sampling and Analysis of Plant Effluents 1

a) BECo Submittal, A. V. Morisi to D. G. Eisenhut, December 15, 1980 ,

b) BECo Submittal, W. J. Merritt to D. G. Eisenhut, February 27, 1981 c) BECo Submittal, A. V. Morisi to T. A. Ippolito, October 16,'1981  !

. i INTRODUCTION _AND BACKGROUND  ;

7 Pilgrim 1 proposes to utilize their present iodine sampling system 'for both routine and accident monitoring of halogen releases. No modifications to the  ;

present system are proposed which would make the system more amenable to sample changeout, transport, and analysis using remote handling techniques to reduce personnel exposures to GDC 19 limits. In the event radiation levels around the sampling system and/or from the sample cartridge itself prevent normal' handling and analysis, Pilgrim 1 proposes to estimate the halogen release rates using the gross gamma response of the High Range Noble Gas Monitor. The use of such estimation techniques, which may grossly over- .

i estimate actual iodine release concentrations, could culminate in unnecessary emergency response actions. ,  ;

LICENSEE'S POSITION Boston Edison Company (BECo), in their letters dated 15 Dccember 1980,  !

27 February 1981, and 16 October 1981 proposes the continued use of their  ;

. present iodine sampling system for both routine and accident monitoring of I I

radioiooine releases from the Unit 1 Pilgrim Nucicar Power Station. BECo states

. . . the normal iodine collection devices would be retrieved and analyzed provided access to the sampling location is available and the

sampling device itself does not result in a dose rate to the operator which i is prohibitive." In the event such accident conditions do occur Pilgrim 1 ,

proposes to estimate halogen release rates from the noble gas gross activity  ;

monitors. Using 'a derived relationship between detector response and noble  ;

gas and halogen release rates, the licensee states it is possible to estimate

, conservative halogen release rates of between 104 and 109 pCi/sec. BECo con-I tenris the estimation technique would certainly result in a higher estimate l of halogen release rates than are actually occurring.

DESIGN BASIS OR REVIEW CRITERIA The design basis and' review criteria for this item are contained in II.F.1 Attachment 2 of NUREG 0737, pages 3-100 through 3-104.

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-c TECHNICAL EVALUATION I i

NUREG-0737,Section II.F.1-2, requires. a licensee to provide the capability  ;

to 1) continuously collect a thirty minute iodine / particulate sample of gaseous effluents containing up to and including 102p Ci/cc, 2) remove the sample from the collecting mechanism, 3) transfer the sample .to an analytical r facility, 4) measure or analyze the accumulated iodine / particulate, and 5)  !

perform all the above without exposing any individual to a radiation dose in  !

excess of 5 rem to the whole body or 75 rem to the extremities. To aid in the development of the licensee's ability to meet the requirements for accident I monitoring, a design basis shielding envelope was recommended by the NRC for i use,as a guidelinein determining the system design criteri.a for sample col-lection, retrieval, transfer, and analysis under accident conditions.

Boston Edison Company (BECo) pr,oposed in their submittal dated 15 December 1980 to utilize their present iodine / particulate collection system to meet [

NUREG-0737,Section II.F.1-2 requirements. BECo noted its intent to review f the current system design and operating procedures and to make any modifications t deemed necessary to fulfill this requirement. BECo also noted the installed noble gas monitor could be used to estimate iodine releases should an accident >

occur at Pilgrim 1 that made the sampling location inaccessible.

In the 27 February 1981. correspondence BECo stated the Pilgrim 1 in. tent to i cstimate radiciodine releases using existing noble gas gross activity monitor in the event an accident occurs which makes the sampling location or sampling device itself inaccessible due to prohibitively high personnel dose rates. The ,

proposed method uses a calculated relationship between noble gas detector re- t i -

sponse and noble gas and halogen release rates. With the method BECo indicated it is possible to conservatively estimate halogen re. lease rates between 10' and 10%Ci/sec or 360 to 36,000,000 Ci/hr. BECo contends this method of est- t imating the halogen release rates will result in conservative estimates of l halogen releases, ie, higher than actual halogen releases, as it assumed in calculating the estimated releases that the ratio of noble gases to halogens ,

in the core and the airborne effluent pathways are the same. The nomograms to be used at Pilgrim 1 for estimating the radiciodine release rates and re-sulting offsite dose rates in relation to the noble gas monitor readings were submitted in the 16 October 1981 letter. .

From the content of the BECo submit,tals and their position taken to estimate halogen releases in the event of an accident prohibiting sample retrieval and analys,is, no modifications have been made which will bring Pilgrim's ex-isting radioiodine/ particulate sampling system into compliance with the re- l quirements of Section II.F.1-2.

ENICO agrees the method of estimating halogen releases using nomograms to  !

relate noble. gas monitor responses with halogen releases can provide a rapid and conservative estimate of the radiciodines being released. However, ENICO t m

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does not believe the proposed method of estimating the halogen releases '

meets the intent of NUREG-0737,Section II.F.1-2. The proposed method can lead to calculated release rates that grossly overestimate the radio-iodine and particulate releases that are actually occurring due, potentially, to very low and/or unknown ratio of halogens to noble gases in the gaseous effluents. The consequences of grossly overestimating radiciodine releases are highly undesirable in the wake of the TMI-2 accident. The advantage actual measurements of haloge'n/ particulate releases provide is the pre-vention of unnecessary public concern and/or emergency response actions, such as evacuation of the surrounding populace. l CONCLUSIONS.

It is the conclusion of this Technical Evaluation Report that the Boston Edison Company's (BECo) Unit 1 Pilgrim Nuclear Power Station has not provided the eonipment and procedures necessary to comply with the require-ments of NUREG-0737,Section II.F.1-2. Instead, the licensee has proposed a technique of estimating radiciodine/ particulate release rate's whic'h could grossly overestimate the actual radioiodine release and could result in the needless activation of emergency evacuation plans. In order to comply with the requirements of Section II.F.1-2, the licensee should provide a system ~

for the sampling, sample retrieval, handling, transport, and analysis of particulate and radiciodine samples of plant gaseous effluents under accident ,

, conditions. Such a system should be designed so that a 30 minute duration

, sample of gaseous effluents with particulate and iodin'e radioactivity con-centrations of 102pCi/cc can be collected, retrieved, handled, transported, and analyzed without exposing any individual to a radiation dose in excess of 5 rem to the whole body or 75 rem to any extremity.

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