ML16245A732
| ML16245A732 | |
| Person / Time | |
|---|---|
| Site: | Oconee, McGuire, 07002623  |
| Issue date: | 04/10/1980 |
| From: | Donohew J Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML16245A502 | List: |
| References | |
| NUDOCS 8004160240 | |
| Download: ML16245A732 (8) | |
Text
UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION BEFORE THE ATOMIC SAFETY AND LICENSING BOARD In the Matter of
)
DUKE POWER COMPANY
)
Docket No. 70-2623 (Amendment to Materials Licens
)
SNM-1772 for Oconee Nuclear Station
)
Spent Fuel Transportation and Storage )
at-McGuire Nuclear Station
)
AFFIDAVIT OF JACK N. DONOHEW I, Dr. Jack N. Donohew, being duly sworn, do depose and state:
I am employed by the Environmental Evaluation Branch, Division of Operating Reactors, U. S. Nuclear Regulatory Commission.
Q. Would you describe your background experience and training that comprise your professional qualifications?
A.
I am qualified by both training and experience to calculate occupational dose from radiation exposure. My professional qualifications were briefly described at Tr. 4434.
A copy of my professional qualifications have been furnished with other documents that have been filed in this proceeding.
Q. What is the purpose of this document?
A.
This affidavit addresses questions concerning occupational doses caused by rupture of McGuire spent fuel assemblies, at least 40 days in age, s
stored in the McGuire spent fuel pool.
The rupture of the spent fuel
-2 assemblies is postulated to be from the impact of a 25-ton truck cask falling onto the spent fuel assemblies stored in the McGuire spent fuel pool.
My affidavit analyzes the occupational dose to employees in re sponse to the request in the Licensing Board's Order of October 31, 2979 which, in pertinent part, states:
. However, regarding the question about consequences of a cask drop into the fuel storage pool, the Board notes that replies to its questions about criticality and radio active emissions to the public were in the nature of summary statements (Tr. 4439-49). The Board therefore requests that the parties supplement these answers with numerical analysis, and include the additional question of radioactive exposure of operating employees.1/
Q.
What is the Board Question concerning exposure to plant workers?
A. Provide a numerical analysis of radioactive exposure of operating em ployees from a shipping cask falling into the McGuire spent fuel pool and damaging McGuire spent fuel.
Q.
What were the assumptions for your calculations?
A. Table 1 enclosed lists the assumptions for the estimate of the exposure to operating employees from the shipping cask falling into the McGuire spent fuel pool and damaging McGuire fuel stored therein. The estimated exposure to workers is based on the expected damage to spent fuel during the postulated accident. The assumptions used are consistent with those used to estimate exposure to the population outside McGuire in the McGuire Final Environmental Statement dated April, 1976.
1/ Order Concerning CESG's Petition to Compel Discovery (October 31, 1979).
-3 Q.
How does the fuel building layout affect your calculations?
A. The ventilation system for the fuel building consists of supply air ducts along one side of the fuel pool and exhaust ducts along the oppo site side of the fuel pool.
Thus there is a sweep of air across the pool collecting radioactivity released from the pool.
The workers can exit the pool area via stairways which are either in the path of the venitlation supply air or of the ventilation exhaust air. I assumed that workers occupying the SFP area during the postulated cask drop exit the pool area through the ventilation supply air path; thus, they are exposed to the gamma rays from the noble gases and radioiod.ine for the conservatively estimated time of two minutes necessary for them to leave the area.
However, if the crane operator inadvertently exits the pool area through the exhaust path he may be additionally exposed to the radioiodines by inhalation. I estimate that he would take 20 seconds to travel the 80 feet along the side of the pool to the stairway exit from the area and would, therefore, receive an inhalation exposure from the radioiodine during this time.
Q.
Does the Licensee have accident evacuation procedures for plant workers?
A. It should be pointed out that Duke Power Company has evacuation procedures for workers to be followed if an accident occurs. In the case of the plants at Oconee/McGuire, the following procedures are used:
Area monitors are located on the SFP Bridge. When a radiation monitoring alarm sounds (in the SFP area and control room), workers are expected to evacuate the area immediately and go to preassigned locations. Alarm
-4 setpoints levels are as follows: For Oconee, a so-called "High-Alarm" is set at 9 mr/hr and an "alert" or evacuation alarm is set at 30 mr/hr.
Personnel would evacuate immediately to the Personnel Change Decontami nation Room, Hot side. For McGuire, evacuation from the SFP area is required in any situation that is likely to expose personnel to an in crease of the background radiation dose rate to 10 mrem/hr. The above levels are much lower than that which could be reached following a heavy load drop accident in the SFP that might cause spent fuel damage.
The licensee has requirements for all plant personnel to be trained in alarm sounds and procedures to respond to these evacuation alarms.
Plant personnel are trained with respect to their evacuation assembly points. Plant personnel are given training in these procedures at their employment date and annually thereafter.
- 0. What is the estimate of plant workers exposure?
A. Calculation of the occupational exposure to personnel in the spent fuel area (SFP) and in the control room following a cask drop accident in the SFP as described above are based on equations in Appendix B, Regulatory Guide 1.109 and the McGuire FSAR description of the spent fuel pool area and control room. These calculations indicate that the exposure to workers in the vicinity of the SFP is less than 100 mrem whole body and less than 300 rem thyroid. The exposure to workers in the control room is less than 1 mrem whole body and 0.1 rem thyroid.
-5 Q.
What are your conclusions based on your calculations?
A. The doses to workers as discussed above are within the exposure guide lines of 10 C.F.R. Part 100 for accidents (i.e., 25 rem whole body and 300 rem thyroid). The whole body doses are also a small fraction of the wuarterly limit (i.e., 3 rem) for occupational exposure to workers in 10 C.F.R. Part 20.
From the above, the staff feels that, by use of administrative procedures and controls, the licensee can keep his occupational exposure to workers to reasonable levels in emergency situations in the SFP area.
I hereby certify that the above statements are true and correct to the best of my knowledge and belief.
Jack N. Donohew Subscribed and sworn to before me this 10th day of April, 1980 Notary Public My Commission expires: July 1, 1982
Table 1 Assumptions for Estimating Occupational Exposure from Postulated Cask Drop in McGuire Spent Fuel Pool Scenario Assumtizon Comments Fuel Assemblies damaced (McGuire fuel) 250 Last refueling 72 Additional Fuel 178 Aae of Fuel damaced Last Refueling 40 days Additional Fuel 365 days
.nctivity Released from damaced Dins 1% of pin activity (activity in cap)
Reduction Factor for Raodioodine Retention in Pool Water 500 ower Level (mw't) 3565
-ruel Exposure time (years) 3 Fuel Assembliies in Core 193 Stay time of cersonnel in vicinity of Dool 2 minutes (2)
Stay time of personnel in radiciodine cloud 20 second (3)
Approxi-zate Dilution Volume above pool 40,000 ft3 (4)
(1)
The number of assemblies in the shadow of the cask.
(2)
Estirated by licensee (stay time for noble gas exposure).
(3) Estimated egress Tor crane operator.. Used for calculation of radioiodine inhabation ex posure if ecress is in direction of exhausted airborne radioactivity.
(4)
Estimated dilution volume based on fuel handling architectual Plans and ventilation fic pathway.
-2 Table 1 (con't)
Dose calculations unite cloud Meteorology for the control room CA 800 m2 Atmospheric dilution 1.25 x 10- sec/r 3 Source Inventory Correction Factors, etc.
See tables 2, 3 and 4 Number of Pins Damaged in Fuel Assembly 96 assemblies all the pins 154 assemblies one row 5/ K.G. Murphy, et. al., Nuclear Power Plant Control Room Ventilation System Design for Meeting General Design Criterion 19, 13th AEC Air Cleaning Con ference.
Table 2 Inventory of Activity in Pool from Cask Drop Accident Curies (Ci)
Radionuclide Oconee Fuel McGuire Fuel 131 1 1.6 27 85 Kr 402 6670 131 Xe 25 427 133 Xe 29 488 Table 3 Adult Dose Factors Used in Calculations (R.G. 1.109)
For Semi-Infinite Cloud I.49 x 1 mrem PCi intake Kr 1.6 x 10 mrem/yr PCi/mI Q
1Xe 9.15 x 10-mren/'yr PC i/m 2.94 x 10 mrem/vr PCi/mn Table 4 Correction Factors for 40,000 ft3 finite cloud Kr
=
0.03 131Xe =
0.139 3e
=
0.07 I
=
0.03