1. Oxygen Deficiency Hazards Analysis for MAJORANA Temporary Clean Room Steve Elliott Los Alamos National Laboratory

2. Outline Background Assumptions – Affected Staff – Design and Delivery Analysis of Failure Modes Conclusions Aug. 20102ODH Overview

3. 40-kg of Ge detectors – Up to 30-kg of 86% enriched 76 Ge crystals required for science and background goals – Examine detector technology options focus on point-contact detectors for D EMONSTRATOR Low-background Cryostats & Shield – ultra-clean, electroformed Cu – naturally scalable – Compact low-background passive Cu and Pb shield with active muon veto Agreement to locate at 4850’ level at Sanford Lab Background Goal in the 0  peak ROI(4 keV at 2039 keV) ~ 1 count/ROI/t-y (after analysis cuts) The M AJORANA D EMONSTRATOR Module 76 Ge offers an excellent combination of capabilities & sensitivities. (Excellent energy resolution, intrinsically clean detectors, commercial technologies, best 0  sensitivity to date) Aug. 20103ODH Overview

4. Temporary Cleanroom site Aug. 2010 Ross Shaft Davis Campus ODH Overview4

5. TCR Aug. 2010ESH Readiness Review Floor paint 5

6. Electrofroming Baths Aug. 2010ESH Readiness Review6 Solution Cu nuggets Deposition mandrel Water 188 g/l CuSO 4 -5H 2 0 75 g/l H 2 SO 4

7. Assumptions - Staffing 7 MJD people initially will require access to the MJD Temporary Cleanroom in the Ross Shop area during commissioning – Mark Horton, Eric Hoppe, one PNNL student, and Dana Medlin for installation of the e-forming equipment – Dave Phillips and Reyco Henning for environmental monitoring and control systems installation. – Steve Elliott or designate. Operations afterwards will use a subset of 2-3 people from the list above and no new people trained. Aug. 2010ODH Overview7

8. Assumptions – Design and Delivery Up to 10 electroforming baths located in TCR Liquid Nitrogen (LN) used to blanket baths – Radon abatement Air recycle rate 13,000ft 3 /s Fresh air flow into room 900 ft 3 /min 157.5 ft 3 /s air flow through drift. No backup generators. Aug. 2010ODH Overview8

9. Assumptions – Design and Delivery LN stored in and supplied from a 180L dewar (depicted by red dot) – one full dewar in area Expanded gaseous N2 – 124.4 m 3 Dewar placed within high air flow of the drift Delivery line shown in red Expect to exchange dewars at max of 6 week intervals Delivery lines ~ 35ft, 18 welds outside baths and one flow regulator Aug. 2010ODH Overview9

10. Assumptions – Design and Delivery Utilized failure rates published in SUL ODH Manual Drift cavity containing the TCR considered an enclosed area Volume of drift approximated subtracting TCR external volume – 415 m 3 Volume of electroforming area is 82 m 3 Air velocity 1.9 to 2.7 knots in drift creates estimated air turnover rate time of 120 to 130 s. Vigorous air flow in TCR ensures complete and instantaneous mixing Aug. 2010ODH Overview10

11. Failure Scenarios Considered 1.Valve connector is severed and contents of dewar spelled onto the floor of the TCR drift cavity 2.Human error in opening the flow valves too much or leak in header system within the TCR 3.Loss of power to ventilation system (assumes restart within one hour) 4.Nitrogen transfer pipe assembly ruptures before the flow meter venting into the TCR 5.Combined errors: a)Loss of vacuum in the dewar combined with malfunction of the regulator valve b)Human error turning regulator wide open combined with pipe rupture in the TCR Aug. 2010ESH Readiness Review11

12. Analysis of Failure Modes ScenarioScenario Description Probability Occurrence/hr, (P i ) Probability of Fatality, (F i ) ODH Fatality Rate /hr, (Ø) I Drift Cavity Liquid Release3 x 10 -11 5 x 10 -6 * 1.5 x 10 -16 II TCR Excess N 2 Gas With HVAC 3 x 10 -3 00 III TCR Excess N 2 Gas No HVAC 10 -6 00 IV TCR Gas Pipe Break With HVAC 10 -8 00 V TCR Gas Pipe Break No HVAC 3 x 10 -1 7 N/A0 Aug. 2010ESH Readiness Review12 * F f reduces to 0 in less than 60 seconds ODH Class = 0

13. Conclusions Product of fatality rate probabilities and failure rates (3X10 -16 /hr) places hazard well within ODH Class 0. Mitigation planned – although not required by class 0 – Oxygen monitors in drift and TCR – Signage with directions if alarm triggers – Training on proper handling of LN and expected response in event of emergency – Monitoring plan with calibration facilitated by SUL Aug. 2010ESH Readiness Review13

14. Davis Campus Aug. 2010ESH Readiness Review14 2 180-liter dewars supply Lab from corridor Empty dewars cycled out and replaced Corridor volume = 154 m 3 Assembly room volume = 363 m 3 Ventilation given as 15 air changes/hr Plan to use commercial vacuum jacketed piping for LN distribution. Possible Vendor: Quality Cryogenics Based on number of systems they have sold and monitored, they estimate a failure rate per bayonet connection = 1x10-8 failures/hr-joint We will have 12-15 bayonet connections Need guidance w.r.t. these estimates We have been waiting for feedback on the TCR analysis before improving this analysis.

15. Failure Scenarios Considered 1.Normal operation boil-off from the 3 dewars overwhelms the ventilation. 2.The LN transfer pipe fails within the assembly room. In this case all the LN within the corridor storage dewars will be vented into the assembly room. 3.One of the 3 dewars loses its vacuum and hence its insulating properties. In this case all the LN within the corridor storage dewars will be vented into the assembly room. 4.The LN transfer pipe fails within the corridor. In this case all the LN within the corridor storage dewars will be vented into the corridor. 5.One of the LN storage dewars fails. In this case all the LN within one of the corridor storage dewars will be vented into the corridor. 6.Normal operation startup will consume LN more quickly than once the detectors are cold. Aug. 2010ESH Readiness Review15

16. Davis Campus Summary Aug. 2010ESH Readiness Review16 ScenarioScenario Description Probability Occurrence/hr, (P i ) Probability of Fatality, (F i ) ODH Fatality Rate /hr, (Ø) I Assembly Normal Operation100 II Assembly LN transfer line fails3 x 10 -6 00 III Assembly Dewar loses vacuum10 -6 00 IV Corridor LN transfer line fails10 -6 4.6x10 -6 1.4 x10 -11 V Corridor LN storage dewar fails 2.8x10 -7 1.0x10 -3 1.0x10 -9 VI Assembly Normal Operation Startup 100 This is a preliminary study that will be refined once we sure we are on the right track.