ML070440477

1996 Water Sample from Torus Room Floor - Pilgrim

ML070440477
Person / Time
Site:	Pilgrim
Issue date:	03/20/1996
From:	- No Known Affiliation
To:	Office of Nuclear Reactor Regulation, NRC/OGC, NRC Region 1
References
96.0096.01
Download: ML070440477 (6)

Text

Extendon: 0 EWAl I I A T l n N Responsibla Manager:

,. d. b Y ~ w &

Status: Operbf.co.+~

Division:

PLANT Significance: 2 Depamnent:

OPS Priority: A Sub Division:

Doc TypeINum bec RPR Titie WATER SAMPLE FROM TORUS ROOM FLOOR SHOWS HIGH TRiTlUM LEVELS INDICATIVE OF PROCESS SYSTEM LEAKAGE Rec'd Date:

I I Due Date: 04/27/96 Assign Date:

03i20196 Dead Date: 05/27/96 Start Date:

03/27/98 Completion Date:

I I 1

Action

-3 CONDUCT AN EVALUATION TO DETERMINE THE CAUSE OF THE WATER FOUND ON THE TORUS ROOM FLOOR DETERMINE CORRECTIVE ACTIONS AND ACTIONS TO PRECLUDE RECURRENCE.

'.? Closure Requirements

- COMPLETE EVALUATION PER NOPQ341, SECTION 6 4 Notes Change@) Approved By:

Date:

I I Change@) Accepted By:

Date: &

1.

Problem

Description:

Water sample h m torus room floor shows high lrilum levels indlcafive of process system leakage Direct Cause: 7he direct cause of the observed water is indel8nTIhal8 without fffrtherinwestig8tions involving physical work and dose. The attached action plan has been developed by NESG and Chemislry to obtain sarnpres of water in a controlled manner lo pennit an evaluafion for cause.

Propased actioii items have bear fewiewed with owners.

2.

3.

Corrective Actiorrs

a.

Taken: None at this firm

b.

Repeat occurrence: Yes

c.

d.

Necessary to precfude recurrence: None at this time Responsible discipline and pemn for implementation: See Action Plan

4.

The significance should: Remain the same Completed by:

Date:

Evaluator Exhibit 4 NOP92A1 Rev.4

Actioii I'lm to Determine Cwsr of Water on the Torus Room Floor Problcni Report Acticia Item PR 96.0096 was when oil March 19, 1990. aftcr pondcd watar on the torus rooni floor was sampled in Bay #6 and found 111 contain tritium. indicative of process water. The tritium concentration was

1. IOE-4 micro Ci/ml (i 49E-7). An action item wits assigned as follows: "Conduct an evaluation to determine the cause of the water found on the torus room floor. Determine corrective actions and actions to preclude recurrence."

3ackground Water on the torus room floor has been a chronic condition over the years and subject to numerous evaluations (Attachment A). The most probable cause is believed to be groundwater intrusion which has by-passed the waterproof membrane encapsulatiq the substructure of rhe Reactor Building and adjacent building. This is based on the following facts:

The groundwater table is estimated to be at EL + I tt. or hiyher around the Reactor Building (Ref

1. I).

We tisve esperienced similar groundwater intrusion in the Radwaste Buildins control room and corridor at EL - 1 ft. at the expansion joint in the abutting floor slabs of thu RadwastdRcactor Building, and the Radwastenurbine Buildings respectively. This was correcled by a modification (Ref #a).

Wc have espedenced known process water leaks (e.g torus trough overflow, torus bottom drains lci~lrage. etc.) in past years which have been corrected and are believed not to be recurring. A wlkdown performed by Operations on 3/27/96 found no evidence of process water leaks onto the tlnor (ReE3).

We have investisated the drywell air yap drains which discharge onro the toms room floor between Bays #6&7, and 14&15. in response to NRC Generic Letter 87-05 and past inspections durins RFO's concluded that these are dry (Ref. 4) Inspections for such leakage during RFO's is an NRC commitment contained in our GL 87-05 response letter.

Wallidowns performed on i O/? 1/96 after a weekend of intense rainfall (4 to 6 inches) and agin on IW18 96 found no differences in the observations made 10/28/96 (Ref 3). Bays #5,6.10 and 1 I Itad pond4 water at tlie low point of the floor under the torus invert. and Bay I5 appeared to bu damp, In soiiie cases the ponded warer seems to have flowed across the sloped floor from the dircction 01' ilie drywell pedestal.

Current S iturrtio n A definitive cause for the torus room ponded water has not previously been pursued beciluse tlie consequences of the ponded water have been acceptable (Le. no significant stmctural degradation to thc Exhibit 4 NOP92A1 Rev.4 TWIMCS9615

raises new qucstions:

I. Can the seepage on llic lloor be traced to B piJitt1 ojcnfry in the concretc stmctlrrc or to n process component:

2. Is the initial test tlrilt irlcntified tritium in the pwtled water repeatable?

3. Is the tritium concctlttiltion in tltc ponded water lltc same as in the air?

4. Could the rritiutn bc II rcsidual product froin :I pIwious process water spill?

5. Could the tritium rcsiil~ from an uridrtrctsd proccss water leak in the torus room?

6. Could the tritium rcsiilt fioni a process water lark into the ground from a component which is outside the Reactor Building migating into the lwiis room through the groundwater?

Data Gathering h data yathering program will be conducted to atteinpt to answer these questions. This will be performed in phases consistent with safety significance and ALARA objectives, and to makc the most effective use of resources and dose budgets. The results from each phase wvjll be reviewed to determine necessity and scope of additional phases.

Phase I Additional information is needed to characterize the nature and potential significance of the tritium in the sample which lead to this PR. This initial phase is designed to provide input lo respond to quesrions I, 2 ;md. A saitrptiny plan is proposed as follows to begin after the torus de-sludge in RFO XI I :

AI& (NESG - G. Dycliman). Perform a detailed v i ~ ~ i d inspection of the concrete floor and wail surhces for a Full 360 degrees under the toms and adjacent io the drywell pedestal to see if the seepage on thc floor be traced to a point of entry in the concrete sttucture or to a process component, 03 AIM. (Plant Services - D. Sukanek).Mer completion of AI.0 t, clean up the existing ponded water and damp areas in Bays i15.G. IO, I 1 and 15. decontaminate the concrete surfaces and dry ilie floor, AlW (Operations - T. Trepmier) Perform inspections of Bays #5.6,10.1 I and 15, during routine operator tours. If seepage on the Ooor is observed, notifj. NESG.

AlM(Cheniistq - D. Fountain) When directed by NESG pursuant to AI.03. obtain samples and test for tritium concentrations and for any other characteristics indicative of a process stream origin.

Concurrently, obtain air humidity sample from the toris rooin. Test these saniples for tritiiiiii concentrations.

ol 04 06

5, Memo "Groundwater Leakage into Torus Ctmp:irtiiient*', NOS82-16XSG S2-SjMED S2-166, dated YlWS2, to R. D. Machon from R. M.

Ulltlrr

6. Memo "Disposition of F&M #81-176". Dhl S7-7KSG SZSOMED 83-1 15. dated 225/S2, to R.

D. Machon from R. M. Butler Attnchment B: Reference Documents I. SUDDSIRF 90-77. Analysis of Groundwater Levels by GEI. dated 2/28/83,

2. FRN 92-0 I-1 1 for repair of Radwaste Building corridor expansion joint f. PR 96.0096 Notes by M. Pedo, 3/28/96, documentins a 5/27/96 toms inspection.

1. BECo Letter S7-073. Response to GL 87-03. dated 5/11/87

5. Specification No. 6498-C-22. Waterproof Menibrane (Sub-Grade Liner Type)

6. Memo "TONS Buttress Repairs I-S2-56-177B. SP 377, dated 10/13/82, to R. M. Butler from H.

F Brannan Exhibit 4 NOP92Al Rev.4

I Problem Report f?d.6L1?&

PROBLEM REPORT Closure Justification: Check one or more of the following andlor provide additional information as required:

Evaluation and Corrective Action Complete Seo Corrective Action Response This issue will be addressed by PR#

This issue will behas been addressed by MR#

Other (See below)

See Evaluation Response uiyi iaiur'e Date 1.3.121 RQV. 5

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