ML20206K698

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Documents Facts Re Failed Fuel,Including Releases to Environ,Exposure of Site Personnel,Operational Limitations & Impact on Ie.Failed Assemblies Permit High Concentrations of Fission Products to Enter RCS & Cause Listed Problems
ML20206K698
Person / Time
Site: Pilgrim, 05000000
Issue date: 07/23/1975
From: Sternberg D
NRC
To: Brunner E
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20204E974 List:
References
FOIA-86-58 NUDOCS 8606300165
Download: ML20206K698 (5)
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E. J. Brunner, Chief, Reactor Operations Branch, IE:1 THRU: D. T.. Diphton, Section Chief , BL'R Proj ects , ROB, IE :I

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PIII;R1111 TUEL PROBwiS i,

f i Although the fact that Pilgrim l's fuel is a problem is uidely recognized, j the impact on plant operations and the IE inspection program may not be j so well known. This memo documents certain facts relating to the failed fuel situation nt pilgrim 1.

l Several diverse topics will be considered including: t elcases to the 1 environment; c> ronure to site personnel; operational J 1mitations; pJans for the future .nd the impact on IE:1.

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General i

Pilgrim l's fuel is basically the original old technology 7 x 7 except I for 20 8 x 8 bundles installed durint; its first outage. It is the same ,

[ type as the original Vermont Yankee fuel and suf fers f rom the GE produc-l tion and OC . problems then existing. The licensee indicates that the j fuel is experiencing both hydriding and pellet clad interaction failures in an estimated 120 assemblics. As a result of these failed assemblics I l relatively high concentrations of fission products enter the reactor l 1

coolant system producing the problems described below.

  • l j nelcases to the Environmeat 4

Due to the abundance of iodine in the coolant system and certain peculiar-l ities of the Pilpin ventilation system, releases of iodine to the atmos-l phere are now running betueen 0.5 and 1 curic per quarter despite the i installation of a functioning Myanced Off-Gas system. As a result of j this situation, the licensec is actively pursuing an Jodine abatement '

I program to reduce this release, including the use of'tuo consulting  !

! firms to locate the release paths and propose corrective measures. It I l should be pointed out that these releases are within the present Tech '

Spec limits which were changed in !!ay 1975 to reflect Appendix 1 con-i

! siderations. This change followed tuo instances of release rate limits  ! ,

j being exceeded and approached on several other occasions. If these l' changes reficcting Appendix I considerations ucre not made as expedi-i' tiously as they vero, continued operation of the facility would have

  • been doubtful. Indirect releases to the environment also occurs in that radioactive vaste, such as spent resin, filter material and con-j centrator bottoms loaded with fission products must be disposed _of.
}!ost of this type of material is shipped of fsite for disposal.

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E. J. Erunner ,

Increaned Snomire to #ite Personnel IMc tr> the Jarre activities in 1,ystcru such as raduaste and the cleanup areas, high doce rates exist in locat forts around the plant ubich requii e accecn Ier opeiat-ion and maint enance. lose rates la t he raduaste area run as high as .00 Ren/hr.

1 Lcvels up to 600 Rem /hr exist in the vicin- l ity of the NC 1ilters and exact detailed survey . in such areas are not taken cue to th: potential exposure of individual s involved in such surveys.

Airborne iodine (an vell as etler isotoies such as cesiun) while precently belov !!PC limit . result ia the enplaiment of respiratory protect ion in i certain areas tbroughout the plant ane.luding raduaste and the Hi'C 1 roen.

Although licensen managenent has a vigorous procran to control exposure it appears that the main obj ect ive of the control syst en la to preclede exceeding the 10 CFR 20 Imit of L Ren/ quarter. Despite this a/ sten, two individuals recently did exceed the 3 Ren limit. This has resulted in an inprou ncut of the accounting and dosinet.ry prencan but has done little to clininnte the cause.

Operational Ltd tations l

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l The plant is cur"catly limit.ing poner to maintain an air ej ector of f ,.. '

rate of about 4 0.1,000,u ci/ s ec . This results in a nax bun power levd o!

about 70% prescat] f uith the strong probability of subsec,uent reducti:

in pover. Subtler changes in plant operation exist; for example, rad-vaste processinn at the end of the second *:alendar quarter was abbre-vinted to r educe the risk of personnel overe::posures. Also certain nonessei.tial c.Matenance is delayed due to high doce rates in arean ubere the uork would be performed. Experiuents with ion exchange resins have also been tried to increase the iodine removal ef ficiency of the cleanup cysten. 11inor stean leaks (uith radioactive f odine) have also required shutdouns for repairs because of the airbcrne  ;

iodine problen eithin the plant and portabic air cican ap syst c:nc are being tried to reduce the concentrations.

Plans f or the Future This section deals prinarily with the refueling plens. Thora are prev i

Of the ently 530 fuel assemblies in the core, 20 of which .are 8 x 8. l remaining 560 assenblics the licensee plans to replace 132 more during I the refueling outage in October 1975. This vill result in a core of 152 out of 580 (26*:) 8 x 8 assemblics. The 132 assemblies which vili be replaced will be selected by a 100% out of core sipping progran which will folleu a high power run to provide inproved sensitivity. I As stated previously, the best estimate to date based on paraneters I r

I E. J. Erunner such as off-gas rate, Vermont Yankee and l'onticello fuel experience, and Gr inferration is that there are 120 or less assemblies presently leak-fog. Used on this, the i: ediat e problen of fuel leakage vill be cor-retted. Houever, .inec 3 /4 o f the co re i n s t 111 7 x 7 type , it is rear,oinb l e to as<at,e that Jeakerc vill develop follouinc. the return to power. As a result. of t!.i.s concern, the licensee indicates that at the next subsequeat refueling another 340-350 assenblies vill be repineel, before the fi, e l depJetion vould othereise require i t , with  ;

8 x 8 fuel. The z erainiaq ')O 7 >. 7 ascenblies vill be placed in lov f]ux, peripheral lecationn. The licer ,ca feels thin vill result in the end of the ft:0 ler. hare prob]w at rijgrim.

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Jha,cj en In:I Die to probleen uith t he fuel, IE:I han spent increased inspection nnd  !

unaage.c.ent e f for t to ensur e operation of the facility within regulatory linits. Thi:. included a great deal of effort relating to the iodine relei:se iscuc and associated Tech Spcc changen as ucl1 as special ALAP rev1ws, and insr.cetions of the iodine abatement program.

In se~ nary, operat ion vit h Jeaky f uel involves considerations reuoved from the fuel itaelf. Such areas discusred above include higher than possible of fsite releases, higher than possible onsite exposure.3, curhi -

soae r Untenance activities, special abatencnt and dositetry prograno, and increased incpection effort to ensure continued compliance with 4.11 regulatory requirenents.

3,m b h D. M. St ernbei'[, '

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Reactor luspector i

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r 7-Sent FacsimilQ to S. Bryan /McKee 8/15/79 h'/

AUG 15 ISIS PROPOSED LETTER (AITS H07001953)

Docket No. 50-293 Sumit University ATTN: Mr. L. Steinman Chaiman, Department of Government Box A Malibu, California 90266 Gentlemen:

This refers to your letter dated July 23, 1979 requesting information relating to the lfal< age d radioactive water at Pilgrim Station, Unit 1, on July 11, 1979.

The licensee's report (LER No.79-027) concerning this leakage is forwarded as an enclosure to this letter. An NRC inspector was dispatched to the facility to observe a portion of the repair work associated with the event. The findings of this inspection will be detailed in the inspection report (50-293/79-13) which will receive public dissemination, Your specific questions and our responses follow.

1) Determine the danger to human life and the environment, from this accident.

There was no measurable danger to human life or the environment from this accident. The source of leaking water was the condensate storage tank.

This tank contains water of low level contamination (approximately 7 x 10-5 microcuries per milliliter). The leakage was collected in the Reactor Building Floor Drain system. That water received processing (ion exchange and filtration) and was returned to the reactor system as makeup water. No measurable release to the environment was involved.

2) Insure that the leak was not in existence longer than 'several' days prior to its discovery.

The magnitude of the leakage was approximately four to five cups of water per hour. Inspection of the steam tunnel area is performed during licensee tours conducted on a daily basis. Because of the small magnitude and low level of contamination of the leak, a definitive detemination cannot be made concerning how long it existed prior to discovery. A higher radioac-tivity level leak or a large volume leak would have been detected by installed instrumentation which provides a warning of such potential hazards.

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3) Determine the original cause of the problem.

The leak was found to be the result of a crack in the heat affected zone of a carbon steel pipe to stainless steel valve weld. The valve was replaced with a straight run of carbon steel pipe, eliminating the bi-metallic junction. The valve purpose is to allow local leak rate testing, and a carbon steel replacement valve will be installed during the 1980 refueling

" outage.

Should you have any further questions concerning this matter, we will be pleased-to discuss them with you.

Enclosure:

Licensee Event Report PPSI-79-021-0!T l

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