ML18346A269

Providing List of Corrections for Errors from Amendment, a New Appendix J Entitled, Evaluation of Postulated Cask Drop Accidents, to FSAR Submitted 8/9/1974

ML18346A269
Person / Time
Site:	Palisades
Issue date:	03/11/1975
From:	Sewell R Consumers Power Co
To:	Office of Nuclear Reactor Regulation
References
Download: ML18346A269 (5)

Text

t.;: *..

').

consumers Power company General Offices: 212 West Michigan Avenue, Jackson, Michigan 49201

• Area Code 517 788-0550

~

~~

~~.~~~

~+/-1:~, >,., ~

. Q. ~-.. 'l~~ '<" {P> {/

~i~:~~; "3" March 11, 1975 Director of Reactor Licensing

~

US Nuclear Regulatory Commission

~ ~

... '/.

Docket 50-255 License DPR-20 Palisades Plant Washington, DC 20555 Gentlemen:

On August 9, 1974, we transmitted an amendment to the Palisades Plant Final Safety Analysis Report (FSAR).

This amendment was a new Ap-pendix J entitled, "Evaluation of Postulate-d Cask Drop Accidents." A review of this amendment has disclosed a number of errors which are dis-cussed below:

1.

On Page J-34, fifth line from the bottom, the words "in-organic and organic" have been transposed.

The correct filter efficiencies were used in the dose calculation.

2.

The dose calculation utilized old X/Q values.

The pro~er X/Q values (taken from FSAR, Page 14.22-7, Rev 5/26/71) have been used in

. recirculation of accident consequences.

Attached are Pages J-33, J-34, J-35 and J-37 which have been ap-propriatedly revised.

Yours very truly; RBS/ce Ralph B. Sewell Nuclear Licensing Administrator CC:

JGKeppler, USNRC 2888

2)

Fuel rac~*nd assemblies.

This equipment could only become damaged as a result of cask tipping.

Section 5.2 discusses the modification which will be made to preclude this.

Even in the event the cooling water return li~es to the spent fuel pool were impacted, it is highly unlikely that the system performance would be degraded to the extent that pool boiling would occur.

In any event, sufficient makeup would. be available from the Safety Injection and Refueling Water Storage Tank and the Fire Protection system to preclude uncovering of the fuel.

For the case that the cask tilts and impacts the fuel racks, 22 fuel assemblies would have to be crushed before offsite doses would approach 10 CFR 100 limits.

This analysis, presented in Section 4.3, is based on an extremely conservative set of assumptions.

J.4.3 ENVIRONMENTAL EFFECTS In the unlikely event of a cask drop into the cask loading area, it is considered extremely unlikely that any fuel assemblies could be damaged.

This is based on the fact that cask movement is made in an east-west direction, between ca.sk washdown pit and cask loading area.

Consequently, cask tipping in the cask loading pit would be expected to affect 11/15/74 J-33

~7-'.

only the portion of the pool west of the loading area as defined by Figure 2.

This area contains no stored spent fuel assen'lblies

• The spent fuel pool can hold 272 fuel bundles, but only 1/3 of a core (91) could have the exposure hypothesized in the previous analysis.

The remaining bundles (if they are in the fuel pool) would contribute much less to the site boundary dose.

Even in the event that the cask could tip in a southerly direction and impact the stored fuel assemblies, a total of 22 stored fuel assemblies, could be damaged before current dose limitations (10 CFR 100) would be violated.

The preceeding study was based on the following assumptions:

1)

Cask drop occurs 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> after shutdown with some number of recently unloaded fuel assemblies reoident in the pool.

2)

Fuel handling area air filters are operative, with all

3) airborne activity released to the atmosphere via charcoal filtration using Regulatory Guide 1.25 filter efficiencies for inorganic and organic iodine of 90 percent and 70 percent, respectively

• Total activity released from the fuel during the accident is assumed to be uniformly released from the building over a two hour period without credit being 11/15/74 J-34

4)

~

taken for r-adioactive decay after release from the fuel

• The dose calculations were based on radioactive releases from the maximum irradiated fuel assembly.

This damaged assembly is assumed to have been removed f r*om the core 4 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> before the accident.

5)

In accordance with the FSAR design basis peaking factor curve, the peaking factor for the maximum irradiated fuel assembly was taken as 2.0.

6)

The decay schemes used are from "Table of Isotopes"

7)

Lederer, etal, and used in the Bechtel Computer code NE602, SOURCE2 to obtain activities 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> after shutdown.

The semi-infinite cloud dose model was used for external doses.

8)

Radioactivity is released at ground level.

9)

X/Q values are calculated from the format presented in Appendix D of the Palisades FSAR.

X/Q values tabulated for 667 meters (2.56Xlo-4 sec/m3) and 4820 meters (2.aox10-S sec/m3) were used for the site boundary and low population zone boundary.*

11/15/74 J-35

(

TABLE 4.3 CASK DROP ACCIDENT DOSES PALISADES CLAD FAILURE AND GAP RELEASE WITH 23' WATER OVERCOVER AND FUEL HANDLING AREA RADIOLOGICAL FILTERS WHOLE BODY Site Boundary LPZ Boundary SKIN Site Boundary LPZ Boundary THYROID Site Boundary LPZ Boundary ASSUMPTIONS RP Factor Partition Factor in Spent Fuel Pool Iodine Noble Gases Organic Iodine Inorganic Iodine in FHA Atmosphere Fraction of Total Assembly Released From Full Assembly I-XE-KR (except KR85)

KR85 rem

.396

.044

1. 75

.188 13.5

1. 48 2

• 01 1.0

.25

.75

• 1

.3 NOTE:

Results are for a single maximum irradiated fuel assembly damaged 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> after shutdown

• 11/15/74 J-37