ML053270507

E-mail from G. Schwartz of Entergy to Various, Regarding Pool Wall Update

ML053270507
Person / Time
Site:	Indian Point
Issue date:	09/19/2005
From:	Schwartz G Entergy Nuclear Indian Point 2
To:	Comiotes J, Conroy P, Cox M, Dacimo F, Thomas Hipschman, Limpias O, Mayer D, Rubin P, Ventosa J - No Known Affiliation, Office of Nuclear Reactor Regulation
References
FOIA/PA-2005-0369
Download: ML053270507 (10)

Text

From: Schwartz, Geoffrey Sent: Monday, September 19, 2005 6:36 PM To: Dacimo, Fred; Limplas, Oscar; Rubin, Paul; Ventosa, John; Comiotes, Jim; Mayer, Don; Conroy, Pat; Hipschman, Thomas; Cox, Mark

Subject:

Pool wall update Attachments: U2SPFSouthWalllndicationR2091905.doc We captured about 500 mL of water from the lower (61.5 ft) indication over a 72-hour period this past weekend and are analyzing it. We analyzed the wall scraping from the pipe pen and found 539 ppm Boron. We continue to consistently see low levels of Cs-134, Cs-137, Co-60 in the sample data from all sources, with the Cs-134 to 137 ratio indicating aging for 6 or more years. H-3 is essentially the same level as the pool. Boron is less than that found in the pool.

We have still drawn no conclusion regarding the source, but the possibilities appear to be a pinhole in the liner, either active or inactive, and/or water from the early 1990s in the tight interstitial between the liner and wall. We are driving to complete the analyses and make recommendations this week. The analyses will include structural impact and radiological/environmental impact. We have a high degree of confidence that the structural impact is negligible based on the calculation accomplished for the early 1990s issue (20-30 gpm for > 2 years).

Updated Action Plan attached (scroll to page 6)

U2SPFSouthWall~nd lcatlonR20919...

Geoff Schwartz Manager, Spent Fuel Dry Storage Entergy Nuclear Northeast, Indian Point Energy Center 450 Broadway, Buchanan, NY 10511 1 Offlcez914) 734-66CFax 914) 271-7191 cC 6 Pae %e'L 3 CONFIDENTIALITY NOTICE: Tiis electronic man transmission IsIntended only for the use of the Individual or entity to which ItIs addressed and may contain confidential Information belonging to the sender which is protected by Entergy or the attorney-clIent privilege. If you are not the Intended redpient you are hereby notified that any disclosure, copying. distribution, or the taking of any action In reliance on the contents of this information Isstrictly prohibited. Ifyou have received this transmission In error, please notifythe sender Irnmedlately by e-mal and delete the original message.

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From: Schwartz, Geoffrey Sent: Thursday, September 15, 2005 5:24 PM To: Dacimo, Fred; Limplas, Oscar, Rubin, Paul; Comiotes, Jim; Mayer, Don; Ventosa, John; Cox, Mark; Conroy, Pat; Skonfeczny, John; Hinrichs, Gary; Sandike, Steven; Lavera, Ron; Hipschman, Thomas

Subject:

Pool wall update Attachments: U2SPFSouthWalllndicationR2091 505.doc We've determined that the moisture in and around the cracks contains H-3.

Attached is an update of the action plan and status. My goal is to present conclusions and recommendations next week. I will be off site tomorrow but Gary Hinrichs (734-6690) will be here and my numbers are listed below.

U2SPFSouthWalIlnd lcat~onR20915...

Geoff Schwartz Manager, Spent Fuel Dry Storage Entergy Nuclear Northeast, Indian Point Energy Center 450 Broadway, Buchanan, NY 10511 POffice.L914) 734-66 Fa,94 27-7191 i Page_ eI1L -j CONFIDENTIALiTY NOTICE: This electronic mall transmission IsIntended only for the use of the Individual or entity to whichl t Is addressed and may contain confidential Information belonging to the sender which Isprotected by Entergy or the attomey-client privilege. If you are not the Intended recipient, you are hereby notified that any disdiosure, copying, distribution, or the taking of any action Inreliance on the contents of this information is strictly prohibited. If you have received this transmission In error, please notify the sender immediately by e-mall and delete the original message.

eoff Schwartz x6+3 Hairline Crack in IPEC Unit 2 Spent Fuel Pool South Wall Revision 5, 9/19/05 1

LBackground I

IPEC is in the process of implementing dry cask storage capability for Unit 2.

This requires that the Fuel Storage Building (FSB) loading bay floor be removed and replaced with a significantly more substantial structure. The original floor has been removed, and excavation of soil and rock in the loading bay is in progress. During removal of loose soil and rocks in the north area of the loading bay (along the SFP south wall), approximately horizontal cracks were exposed at an elevation of approximately 65 feet, and an approximately vertical crack above.

The cracks are very narrow (less than 1/64-inch wide). One of the cracks, on the west side of the south SFP wall, has moisture in and near it.

SFP wall structure In the area of the crack, the SFP wall isL

.4-JThe cracks have been visually inspected by an IPEC civil/structural engineef ,and the IPEC Supervisor of Civil/Mechanical Engineering. The condition is typical of cracking due to shrinkage during post-construction concrete curing. The moisture in and around/

one of the cracks is very slight, essentially a film which is not dripping or beading The moisture has been analyzed and found to contain trace amounts of Cesiumk 134 and 137, Cobalt-60, and Boron. The Boron concentration is about 6 to 15 times less than the concentration in the SFP, and the ratio of Cesium-134 to 137 indicate the activity is about 6 to 10 years old. The crack has calcium stains emanating from it, as is expected when moisture leaches through concrete, and no visual evidence of steel corrosion products (rust). Due to the thickness of the SFP wall, amount of steel reinforcement, and lack of evidence that the small amounts of moisture and boron have caused corrosion of the reinforcing rods, there is reasonable assurance that the SFP wall is structurally sound and capable of performing it's intended function.

ial sources of moisture The moisture in and around the crack could be from one or a combination of several sources.

1. A leak, either active or in the past, through the SFP stainless steel liner,

)and leach through the-wall into the crack.

a. The Unit 2 SFP does not have a leak detection system. Usually such a system consists of a drain pathE 2

1 ~(lUnit 3 has such a Teak detection system). The Unit 2[

j An active leak, depending on it's age and volume, could be determined when it develops by a change in frequency of pool water make-up and/or a change in pool boron concentration. A discussion with Unit 2 licensed operators indicated the frequency of make-up has not changed, other than that expected due to seasonal changes in pool water evaporation rate, and as a separate attachment to this paper, a trend graph of boron concentration in Unit 2 SFP is attached indicating no unexpected/unexplained loss of boron. However, due to the lack of a leak detection system, and the large volume of pool water normally lost due to evaporation, a small liner leak could go undetected.

b. Based on isotopic ratios and radionuclide type, the existence of radionuclides such as Cesium and Tritium in the moisture could provide an indicator of whether there is an active leak, or whether the moisture source could have been from a since-repaired liner leak. Soil and moisture samples are being collected and will be sent to a laboratory for analysis which can detect the presence of Tritium.

2. Contamination of the soil in the FSB loading bay, above and adjacent to the moist crack, and subsequent entry of contaminated liquid into the crack due to hydraulic pressure from the loading bay side.

Historical information

1. Inthe northeast area of the SFP stainless steel liner at about the 89 foot level, a small hole occurred during a 1990 pool re-racking project. The damage was discovered in 1992 when boron powder was found on the SFP east exterior wall. During subsequent radiological recovery and repair of the hole, outside soil adjacent to the SFP east wall was found to contain Antimony-124 and 125, and Cesium-137. Approximately 100 55-gallon barrels of soil, down to a depth of eight feet below grade (72 foot level) required remediation. The leakage through the hole in the pool liner was estimated to have been 20-30 gallons per day, which was unnoticed due to the much large volume of normal evaporative loss from the pool.

2. The original.loading bay floor had a drain system (see attached elevation sketch), above and adjacent to the area of the moist crack, which was piped through the wall separating the FSB loading bay and SFP heat exchanger room to a sump in the heat exchanger room. When the floor was removed in 2004 for the dry cask storage modifications, the drain pipe was found to be cracked, and the wall penetration through which the drain 3

pipe was installed was found to be unsealed. Discussions with personnel who were working at Unit 2 at the time indicated that in years past, the level in the sump rose above the drain pipe penetration.. This, along with the cracked pipe, resulted in contamination of the soil beneath the floor.

Contamination of this soil, primarily in the northwest area of the loading bay, was found and remediated during excavation in 2004 and 2005 for the dry cask storage project.

3. From 2003 through 2005, various activities associated with the dry cask storage project in the area above and adjacent to the crack required the use of water as a dust-inhibiting and cooling measure, which was allowed to drain into the FSB loading bay soil. These activities included core-boring, saw cutting of the original loading bay floor, and excavation, Six core-bore samples, to a depth of greater than 20 feet, were taken in the FSB loading bay (four cores), and FSB access roadway (2 cores) in 2003 during the dry cask storage engineering study activities.

Industry operating experience In September 2002 the Salem nuclear plant found evidence of contaminated water leaking through a wall and onto the floor of the auxiliary building. This leak was found as a follow-up to unexpected shoe contaminations. There were other leaks through walls and penetrations that appeared to be originating from the Unit 1 SFP. It was determined that the tell-tale drains for the SFP were plugged with debris, so there was a build up of hydrostatic pressure between the liner and concrete wall.. This caused the leakage to find alternative through-wall paths.

When these drains were cleaned, the leakage flowed to a collection system, essentially terminating the through wall leakage. The pool leakage was then identified via the drain system. This pool leakage occurred for an indeterminate time.

Salem conducted sampling and analysis of the environment surrounding Unit I FSB, in a phased approach, to identify potential release of the water outside the building confines. On February 6, 2003, Salem found tritium (H-3) contamination in close proximity to the Unit 1 FSB. By now the tell-tale drains were functioning, so the through wall leakage had stopped. Salem reviewed other spills that could have contributed to the tritium contamination.

Salem performed test core borings in various site locations and initially identified five areas with varying tritium contamination levels. 37 well locations were installed around the site to better characterize the extent of contamination, and 30 of the areas found some tritium contamination. There Were no locations that found tritium in unrestricted-access areas 4

Action Plan The following actions (see next page) are being implemented to aid in determining the source of moisture, potential amount and extent of related soil contamination, conclusions, and remediation/repair plan and schedule.

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1. The IPEC Manager of Dry Cask Storag 9 Schwartz, ) as overall responsibility for executing this plan, upd and keeping senior management, NRC, Unit 2 ShftM er informed daily. The IPEC Diredbr of Special P; Mayer, x552 <who has responsibility for Health Physics Department) will assist.

2. (Manager ofEDry Cask Storage) Issue Condition Report ancd submit Operability Evaluation information to Shift Mana develop and issue ODMI. CR-IP2-2005-03557 included Operability Evaluation). ODMI issued.

413. (Radiological Waste Department) Take radiological samples at damp crack, and take dirt samples from where excavation material was placed. Complete, see discussions below.

4. (Civil-structural Engineering) Determine rebar location in relation to cracks, using a rebar detection device. Completed 9 05. Rebar is  :]to cracks.

5. (Radiological Waste Department/Civil-structural Engineering) Hand-drill (small diameter bit) several inches into the SFP wall in the area of the moist crack and analyze drill-bit finds for contamination. Completed 9-7-05. Finds appeared to be damp in first several inches of depth, then appeared to be dry.

6. (Radiological Waste Department) Place a plastic covering over the moist cracks to attempt to capture of a sufficient volume of liquid for radiochemistry analysis. Collected 12 mL sample 9112-13105. Contained low levels of Cs-137 and Co-60.

Contained approximately 1265 ppm Boron and approximately .02 micro-cImL H-3. This indicates the moisture is from the pool. Approximately 500mL captured from lower crack over weekend of 9116 through 9118. Analysis results expected by 9120105.

7. (Chemistry Department) Sample the soil beneath the area of the crack for H-3. Sample collected, sent off-site to laboratory for Tritium analysis. 'Results received 913105, indicating low level H-3 near (within a foot) of the wall, decreasing within 2-3 feet to nearly undetectable.

8. (Chemistry Department) Scrape material from an unaffected area of the SFP wall and test for boron content. Used dry finds from drilling, low-level Boron detected (less than 400 ppm).

9. (Civil/structural Engineering) Determine the typical level of boron in clean concrete. Attempted, no information available.

10. (Civil/structural Engineering) Determine expected corrosion rates for steel reinforcing rods subjected to an environment containing boron. See #11 and #19 below.

11. (Licensing Department) Gather historical written records on SFP stainless steel liner damage and SFP sump overflows.

Some Liner damage information recovered, including Calculation CGX-00006 (Structural Evaluation of Unit 2 Fuel Pool Wall) and Technical Report ME-3802 (Evaluation of Spent Fuel Pool Walls - 1P2 NPP). These are considered bounding for the current situation in terms of wall and rebar structural integrity. No information on sump overflows (other than tribal knowledge) has been recovered.

12. (Civil/structural Engineering) Arrange a ground-penetrating radar (GPR) inspection (or other methodology) of the crack to determine Qfpossible) crack depth. GPR determined not feasible. Two 4-inch diameter cores, L

'were taken 9-8-05 in the area of the moist crack. One appeared to be dry on 9-8-05 and it is presumed this was affected by boring bit heating. 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> later on 9-9-05 it was damp. The rebar exhibits normal surface oxidation. Visual inspection on 9112105 to 9119105 appears to indicate moisture is lessening.

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13. (Chemistry Department) Determine if a Unit 2 Spent Fuel Pool Integrity Evaluation from Tritium Measurement, was performed, similar to that performed for Unit 3. Not performed for Unit 2. TBD whether to perform this, as it requires a lengthy period of data collection.

14. (Radiological Waste and Chemistry Departments) Gather radiological results of test core borings accomplished for dry cask storage inside FSB loading bay (4) and in FSB loading bay access road in 2003. Completed. Low-level surface contamination was found consisting of Cs-134, Cs-137, Co-58 and Co-60.

15. (Manager of Dry Cask Storage) Bring in expert structural engineer and bring in expert help to assist in managing this issue; both with past experience in SFP leakage. Additional resources are on board.

16. Conduct Challenge Meeting with IPEC management. Completed 9112105.

17. Contact JAF to obtain input based upon recent experience with leaking Spent Fuel Pool liner. Conference call conducted with JAF 9113105. Discussed conditions and status of IPEC issue, and draft ODMI. No additional recommended actions were suggested, however valuable information was learned - JAF had an active pool liner leak earlier this year, but the leakage has appeared to cease on it's own, potentially indicative of a pinhole forming then being closed by some debris, or by the leak path (crack in concrete) being closed in some manner.

L 18. Inspect bther accessible exterior areas of SFP wall. Other accessible areas in addition to the south wall include the 1S west wall in the pipe penetration space ("Pipe Pen"), the west walIL ]and the east wall F J The east wall has no ej~dence of a prob em subsequent to the 1990-92 leak. The west wallr_ ]has.some dry cracking and dry white streaking with no evidence of moisture at the same level as the damp cracks on the south wall. The white material was sampled for radiochemistry and found to have 539 ppm Boron and trace amounts of Cs 134, 137 and Co-60.

The westwallE . jjhas some shrinkage cracking but no evidenceof moisture.

£y.., 19. (Manager of Dry Cask Storage) Issue final version of this paper with conclusions and recommendations for physical actions (as deemed necessary, such as repairs, test wells, etc.) and schedule. This will include a calculation of seepage rate of pool water through the wall (draft calculation indicates 200 mL through the liner at 30 feet of head per day would require approximatelyjhours to travel through a through-wall crack in theQ -]of the SFP wall), and characterizations of environmental impact and structural impact, as well as a schedule for impleme-ation of recommended physical actions. Target 9-23-05.

Summary as of 9119105 Due to the thickness of the SFP wall, amount of steel reinforcement, small volume of moisture and boron impingement on the reinforcing rods, there is reasonable assurance that the SFP wall is structurally sound and capable of performing it's intended function. This is additionally supported by the bounding calculation and study referred to above.

The data collected so far appears to indicate either a pinhole (active or inactive) in the SFP liner, or interstitial water in the tight void between the liner and concrete from the 1990-92 leak . Location and whether the leak path is active is undetermined. As indicated in #19 above, a final version of this paper with conclusions and recommendations for physical actions (as deemed

.7

necessary, such as inspections/repairs, test wells, etc.) is targeted to be completed this week. This will include a calculation of seepage rate of pool water through the wall, and characterizations of environmental impact and structural impact, as well as a schedule for implementation of recommended physical actions 8