DOE 2000. - Waste Isolation Pilot Plant - U.S. Department of Energy

WIPP RH PSAR DOE/WIPP-03-3174 CHAPTER 5
Damage Ratio (DR)
Based on the discussion in Section A.3.2 of DOE-STD-3009-94, 1 material actually impacted by the
accident generated conditions are acceptable for estimation of the DR. There are no releases from fires
involving the 72B cask and/or canister. Since the fires included in the accident analysis for 10-160B cask
processing are external to the waste drums, the amount of the combustible material that is actually burned
is limited by the amount of oxidant (air) that is present in the drum to support combustion. The analysis
performed for the CH TRU Central Characterization facility showed that only 16.3 percent of the
combustible material in the waste drums is actually burned. As a result of the airborne release generated
by the fire phenomenon, it is assumed that the conservative radiological DR for the 10-160B fire events
is 1.0 (DR=1.0) while the non-radiological DR = 0.163.
For waste canister or drum breaches from drops, two specific accident conditions are examined: (1)
drops from heights less than 4 ft (1.2m) (h #4 ft [1.2m]) and (2) drops from heights equal to or less than
22 ft (6.7 m), [4 ft (1.2 m) < h #22 ft (6.7 m)]. It is assumed that a waste canister inside the facility cask
will maintain its structural integrity and its containment function if the facility cask is impacted by a
forklift or if it is involved in a collision with another vehicle while being transported by a forklift.
For waste canister or drum breaches from drops, the DR is based on the extensive analysis performed for
the CH waste drums. That analysis showed that for DOT Type A drums weighing 1000 pounds or less a
conservative DR of 0.025 for drops of greater than 5 feet but less than or equal to 10 feet is applicable.
This drop height is typical of drops from the cranes and manipulators involved in handling the waste
drums from a 10-160B cask. The DR for waste drum breach accidents involving dropping a waste drum
is 0.025 ( DR = 0.025).
Another type of accident involving breach of a waste drum involves dropping a heavy object, such as the
Hot Cell shield plug, on a waste drum. The DR is a function of the kinetic energy which is in turn a
function of the weight of the dropped object. In this case, the drum is not dropped but is impacted by a
dropped object. The result on the drum is the same. Since the weight of the object dropped on the drum
could be more than the 1000 lbs used for the basis for the DR for dropping a waste drum, it is assumed
that the DR for this case is larger than the 0.025 value for a drum drop of between 5 and 10 feet. The
shield plug weight is approximately 4 times the 1000 pound weight of a waste drum, it is assumed that
the impact of the shield plug on a waste drum would result in a DR four times the DR for dropping a
1000 pound waste drum the same height. It is conservatively assumed that the DR is (4 x 0.025 = ) 0.1
for this event.
The other two types of accidents involving the breach of a waste drum are puncture scenarios. In one
scenario, an unprotected waste drum is punctured during waste handling operations. From section
5.2.1.1 of the WIPP CH SAR 6 , the DR for DOT Type A waste drum breached by impact with waste
handling equipment is 0.05 ( DR = 0.05). The other puncture accident involves puncturing a waste drum
while contained in the 10-160B cask. Since this would require penetrating two barriers, the DR would be
smaller than the DR for puncturing an unprotected waste drum. The DR for double confined waste is a
factor of 10 lower than single confined waste. Based on the ruggedness of the 10-160B cask, it is
conservatively assumed that the DR is a factor of 2 smaller than the DR for puncture of an unprotected
waste drum. The DR for puncturing a waste drum inside a 10-160B cask is 0.025 (DR = 0.025).
5.2-6 January 22, 2003