ML20155H153

Licensee Testimony of Ww Weaver on Accident Risks (Contention 2).* Related Correspondence

ML20155H153
Person / Time
Site:	Three Mile Island
Issue date:	10/11/1988
From:	Weaver W GENERAL PUBLIC UTILITIES CORP.
To:
Shared Package
ML20155H117	List: ML20155H114 ML20155H128 ML20155H140 ML20155H153 ML20155H166 ML20155H175 ML20155H190
References
OLA, NUDOCS 8810180279
Download: ML20155H153 (8)

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October 11, 1988 1

UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION BEFORE THE ATOMIC SAFETY AND LICENSING BOARD

. In the Matter of )

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GPU NUCLEAR CORPORATION ) Docket No. 50-320-OLA

) (Disposal of Accident-(Three Mile Island Nuclear ) Generated Water)

Station, Unit 2) )

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LICENSEE'S TESTIMONY OF WILLIAM W. WEAVER ON ACCIDENT RISKS (CONTENTION 2) i I

881010027988gh20 PDR ADOCK O PDR 0

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Q.1 Please state your name. l A.1 William W. Weaver.

Q.2 Mr. Weaver, by whom are you employed, and what is your  ;

position?

A.2 I am a self-employed consultant for GPU Nuclear Corpo-  ;

ration ("GPUN") at Three Mile Island Nuclear Station, Unit 2

("TMI-2").

Q.3 Please summarize your professional qualifications and experience relevant to this testimony.

A.3 I have a B.S. degree in Marine Engineering, a M.S. de-gree in Nuclear Engineering, a M.B.A. degree and have completed all course work for the Doctorate in Business Administration and operations Research. I am certified by the American Society for Quality control as a quality engineer and as a reliability engi-neer. I am responsible for developing probabilistic risk assess-ments for TMI-2. I have over 12 years experience in the field of probabilistic risk assessment. I previously was supervisor of probabilistic risk assessment at Babcock & Wilcox Company. A complete statement of my professional qualifications is appended as Attachment 1 to this testimony.

Q.4 What is the purpone of this testimony?

A.4 I will address the issues remaining on the risks from accidents associated with GPUN's proposal to evaporate the THI-2 Accident-Generated Water ("AGW") and with the alternative raised  ;

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h by the Joint Intervenors involving on-site storage followed by disposal. In addition, I will specifically address the Licensing Board's conclusion in its August 25, 1988 Memorandum and order regarding the dose calculations from an accident involving the Joint Intervenors' alternative.

Q.5 What are the potential risks associated with the evapo-ration proposal?

A.5 The evaporation process is estimated to last from 15 to 24 months. During that time, the AGW will be rtored in an ap-proximately 500,000 gallon tank prior to being vaporized. The probability of an uncontrolled release from the staging tank is estimated to be 0.17 over a 24-month period with a resulting dose of 2.50 mrem from the liquid pathway and 1.79 mrem from the air-borne pathway to the. critical organ-the bone.

The transportation of evaporator bottoms to a disposal site involves radiological and non-radiological risks. Radiological risks include occupational dose to drivers and handlers of AGW and dose to members of the general population. The general popu-lation dose consists of routine dose exposure to by-standers and other vehicular parsengers in addition to accident dose due to transportation mishaps.

It is estimated conservatively that disposal of evaporator bottoms will require 8 to 12 truck shipments to the burial site.

l The average activity of each shipment is expected to be less than i

0.5 curies total activity. The shipments are assumed to travel

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( Il along the least risk route (in terms of population density as de-termi'ed by INTERSTAT computer code) from TMI to Hanferd, Washington, which would be an estimated distance of 2800 miles.

Using the RADTRAN computer code, the incident free population dose from 12 shipments vould be 10.4 person-rem. The estimated dose to the driver per shipment is 95 mrem.

The expected number of traffic accidents and fatalities for these shipments is 0.049 and 0.002, respectively. Taking into account the severity and probability of the accident, the popula-tion density along the least risk route, and the resulting re-lease fraction of radionuclides produces 0.003 person-rem expect-ed from these shipments.

In addition, the preprocessing of 31% of the AGW will pro-duce approximately 40 liners which will require 20 to 40 ship-ments for disposal and represent a disposal volume of 6,200 ft3, The expected number of traffic accidents and fatalities resulting from disposal of these liners is 0.093 and 0.0038, respectively. l The (xpected dose to each driver would average approximetely 15 mrem per shipment. The incident free dose to the general popula-tion from these shipments is 4.8 person-rem, and taking into account the severity and probability of an accident, the estimat-ed accideat dose is 0.56 person-rem.

Q.6 What are the risks associated with the Joint Interve-nors' alternative for disposition of the AGW involving on-site storage followed by disposal?

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T A.6 Storage of the AGW on-site presents the continued risk of a radiological accident. An uncontrolled release could occur as a result of damage to one or more tanks due to an external event or due to tank failure (e.g., leaks due to the aging pro-cess). External events that were found to contribute to the re-lease probability include airplane crashes, tornados, floods and seismic events. The probabilities associated with the occurrence of external events that could cause a breach of the AGW tanks were derived from the Probabilistic Risk Assessment performed for THI-1, analyses performed for the Probabilistic Risk Assessment for TMI-2, data contained in the TMI-2 FSAR, and data obtained from the Harrisburg Office of the U.S. Department of Interior, Geological Survey Water Resources Division. The probabilit'y of a leak or rupture can be examined from comparable tank failure rates.

The probability of an uncontrolled release over the 30-year period has been estimated to be roughly 3.75%. The weighted av-erage release (at the fifteenth storage year) results in 5.3 mrem via the inhalation pathway and 7.1 mrem via liquid release path-vays to the maximally exposed individual.

Q.7 On page 15 of its Memorandum and Order of August 25, 1988, the Licensing Board stated:

The only credible accident identified for this alternative (the "no-action" alternative] is tank rup-ture, which in the worst case would result in discharge of the entire contents of a tank in a short period of time. Ibid. Staff estimated that the 50-year dose to l

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the maximally exposed individual in the event of an ac-cidental spill from an ll,000-gallon storage tank would be 0.015 mrem to the bone and 0.002 mrem to the total i body. The collective 50-year dose commitment to the l affected population would be 0.7 person-rem to the bone and 0.015 person-rem total body. Id. at 3.8-3.9.

Is this correct?

A.7 No. The Board apparently is discussing the worst case scenario for an accident under the "no-action" alternative. How-ever, the Board is using the Staff's accident analysis for the evaporation proposal. On pages 3.33 and 3.34 of PEIS Supp.

No. 2, the Staff presents its accident analysis for the "no-action" alternative. There, the Staff states:

The only credible accident identified for this alterna-tive (the "no-action" alternative) is tank rupture, which in the worst case could result in discharge of the entire tank contents in a short period of time . . . . The prompt acci-dental discharge of 2.3 million gallons (8.7 million liters)

, of this water would result in a bone dose of 3 mrem and a total body dose of 0.4 mrem for the maximally exposed indi-vidual, assuming that individual ingests water and fish from the Susquehanna River and participates in recreational ac-tivities such as swimming and boating. . . .

The collective 50-year dose commitment to the popula-tion is estimated to be 40 person-rem to the bone and 1.0 person-rem to the total body from ingestion of drinking water and fish from the river, participation in recreational activities, and consumption of shellfish from the Chesapeake Bay. The total 50-year dose commitment to the larger popu-lation would contribute 100 person-rem to the bone ano 3 person-rem to the total body. These doses would be lower after some radioactive decay.

Therefore, the data presented on pages 3.33 and 3.34 is the Staff's accident analysis for the "no-action" alternative.

Q.8 On page 25 of its Memorandum and Order of August 25, 1988, the Licensing Board concluded:

(T]he dose commitment resulting from an acci-dental discharge from a tank would be very small, representing a small fraction of the radiation dose that would result from forced evaporation.

Is is correct that the dose resulting from an accident during the Joint Intervenors' alternative would be a small fraction of the dose resulting from forced evaporation?

A.8 No. According to the testimony of Dr. Baker, the esti-mated doses to the maximally exposed hypothetical off-site person for the duration of the evaporation process will be 3.6 mrem to the bone and 2.0 mrem to the total body. By contrast, the weighted average release from an accident involving the Joint In-tervenors' alternative results in 5.3 mrem via the inha.'ation pathway and 7.1 mrem via liquid release pathways to the maximally exposed individual. Thus, the dose commitment resulting from an accident during the Joint Intervenors' alternative would be greater than the dose commitment resulting from the evaporation process.

Q.9 Mr. Weaver, in conclusion, how would you compare the risks from accidents associated with the evaporation proposal and the alternative identified by the Joint Intervenors?

A9 The risks from accidents associated with the evapora-tion proposal are definable and not significant. By contrast, all of the risks associated with the Joint Intervenors' Y

alternative cannot be identified. At this time, I can identify the risks associated with the storage component of the Joint In-tervenors' alternative. However, there are additional risks from ultimate disposal which must be factored into the accident analy-sis for the Joint Intervenors' alternative. In my view, on the basis of risk analysis alone, the better course of action would be to go forward with the evaporation proposal now and not in-crease the risks and exposures to the public by continued storage of the AGW followed by eventual disposal with all of the atten-dant risks of both storage and disposal.

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