ML20197A860
| ML20197A860 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 12/17/1997 |
| From: | Cruse C BALTIMORE GAS & ELECTRIC CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| IEB-96-004, IEB-96-4, NUDOCS 9712230228 | |
| Download: ML20197A860 (5) | |
Text
_
CZArtis 11. CcosE Bdrimore Gr.s axi Electric Company Vice President Calven Cliffs Nuclear Power Plant Nuclear Energy 1650 Calvert Cliffs Parkway Lusby, Maryland 20657 410 495 415, December 17,1997 U. S. Nuclear Regulatory Commission Washington, DC 20555 ATTENTION:
Document Control Desk SUILIECT:
Calvert Cliffs Nuclear Power Plant Unit Nos.1 & 2; Docket Nos. 50 317 & 50-318 Calvert Cliffs Independent Spent Fuel Storage Installation, Docket No. 72-8 Response to NRC Request for Additional Information Regarding Bulletin 96-04:
Chemical, Galvanic, or other Reactions in Spent Fuel Storage and Transportation Casks
REFERENCES:
(a)
Letter from Ms. M. G. Dailey (NRC) to Mr. C.11. Cruse (BGEL dated November 17, 1997, Request for Additional Information Based on the Nuclear Regulatory Commission's Acceptance of VECTRA Technologies' Response to NRC Bulletin 96-04 (b)
Letter from Mr. L. ii. Cruse (BGE) to NRC Document Control Desk, 3
dated August 19, 1996, Response to NRC Bulletin 96-04: Chemical, Galvanic, or other Reactions in Spent Fuel Storage and Transportation Casks (c)
NRC Bulletin 96-04: Chemical, Galvanic, or other Reactions in Spent Fuel Storage and Transportation Casks, dated July 5,1996 By letter dated November 17,1997 (Reference a), you informed us of your acceptance of the information prepared by VECTRA Technologies, Inc. in response to NRC Bulletin 96-04, " Chemical, Galvanic, or other Reactions in Spent Fuel Storage and Transportation Casks" (Reference c), which was incorporated in our response to Bulletin 96-04 (Reference b). In your November 17,1997 letter, you also enclosed a request for additional information (RAI) regarding our iinpleinentation of the recommendations made in VECTRA's response, wnich " supersedes in its entirety [your) RAI dated April 8,1997." Attachment (1) to this letter provides our response to your latest RAI enclosed in Reference (a).
t 3
N..
l\\
l.itI.ltl.l!ll.Lil. I U. Y.
9712230228 971217 PDR ADOCK 05000317 G
i r,
- Document Control Desk 0ccomber 17,1997(
e.'
-! Page 2
- Shuuld you have questions regarding this matter, we will be pleased to discuss, them with you, i
Very truly yours, m j- ;
4bu
~
g k
STATE OF MARYLAND 4
- TO WIT:
COUNTY OF CALVERT.
i1," Charles Hi Cruse, being duly sworn, state that I am Vice President, Nuclear Energy: Division.
i TBaltimore Gas and Electric Company (BGE), and that I am duly authorized to execute and file this response on behalf of BGE. To the best of my knowledge and belief, the statements contained in this documem are true and correct. To the extent that these statements are not based _on my personal i
knowledge, they are based upon information provided by other BGE employees and/or consultants. Such iinformation has been reviewed in accordance with company practice and I believe it to be reliable.
istW W
-%s.-
/
Sub ' bed and sporn before me, q Notary.Public iq and for the State of Maryland and County of
, ', ~ _ M/z2wli
.this hYtlayof fjuvdo.1997.
g-WITNESS my lland and Notarial Seal:
Ath(A 8
[O V'
Notary Pubiic
~
u-
- =
110TARY Pt.:d,UJ Siid a OF k./J/ LAND My Commission Expiros JJy 1,199g
- My Commission Expires:
MutIfC
. /fM Date CilC/GT/ dim
_ 1)! = Response to the NRC's No 7mber 17,1997, Request for Additional Information
Attachment:
(
Regarding Bulletin 96-04, " Chemical, Galvanic, or other Reactions.in Spent Fuel Storage and Transportation Casks"
=c6:
. R. S. Fleishman, Esquire
- Resident inspector, NRC M. G. Bailey, NRC
- J. E. Silberg, Esquire :
m E A. W-Dromerick, NRC-R. I. McLean, DNR
- /
j Director, Project Directorate 1 1, NRC J. II.. Walter, PSC :
o
=
' H. J.' Miller, NRC.
D. Dawson, Trans Nuclear 1j
ATTACHMENT m a
P Response to the NRC's November 17,1997, Request for Additional Information Regarding Bulletin 96-04," Chemical, Galvanic, or other Reactions in Spent Fuel Storage and Transportation Casks"
- Baltimore Gas & Electric Company Docket Nos. 50-317,50 318, and 72-08 Decemher 17,1997
ATTACHMENT 11)
Response to the NRC's November 17,1997, Request for Additional Information Regarding Bulletin 96-04, " Chemical, Galvanic, or other Reactions in
- Spent Fuel Storage and Transportation Casks" NRC Reques Describe in detail how the recommendations made in the VECTM Technologies, Inc. (VECTM) Report
. No. 31.B9604-102, Revision 2, for hydrogen control and monitoring will be implemented. At a minimum, the irtformation provided should:
1.
Describe the methods used to control and monitor indrogen before and during welding, grinding, or cutting operations associated with loading or unloading activities.
The methods should inchide continuous monitoring of the Indrogen concentration in dry shielded canisters (DSCs) with flame-sprayed aluminum. During its review of VECTM's evaluation, the staffound that the hydrogen concentration could be highly variable in these DSCs. In addition, restdts of VECTM's computer simulation also indicate that there may be an initiating event that causes a rapid increase in hydrogen generation. If not properly monitored, the indrogen concentration could exceed VECTM's proposed safe upper Ilmit of 2.4% hydrogen, and the lowerflammability limit of 4.0% hydrogen in a very short time in barated water.
2.
Specify the DSC Indrogen concentration that will be set as the safe upper limit before and during welding or cutting operations.
VECTM has recommended a safe upper limit of 2.4% hydrogen. If a higher limb is used, Justify that it provides an adequate safety margin between the amount of hydrogen produced and the lowerflammability limit (4% hydrogen by volume).
3.
Describe the actions to be taken of the sqfe upper limit is exceeded.
BGE Response:
1.
In our August 19,1996 response to Bulletin 96-04 (Reference 2), we indicated that our plan was to sample a number of DSC operations involving carbon steel coated with flame-sprayed aluminum, and reevaluate the situation whether to continue sampling. However, since the NRC staff has expressed its belief in continuous monitoring of the hydrogen concentration in DSCs with flame-sprayed aluminum (Reference 1), we will continuously monitor the DSC vapor space during welding or cutting of the shieM plug to ensure that VECTRA's recommended safe limit is not exceeded.
As described in Reference (2), we use two procedures to control all Independent Spent Fuel Storage Installation (ISFSI) welding, grinding and cutting operations; ISFSI-01 for loading activities and ISFSI-02 for unloading activities. Both procedures use the same general method to control and monitor hydrogen during operations involving DSCs containing carbon steel coated with flame-sprayed Aluminum. The following is a description of the method used during a loading activity:
- Before the Transfer Cask /DSC is placed into the Spent Fuel Pool, the Vent Port Fitting is removed from the DSC. This creates a clear 1/2-inch path for any gases to leave the DSC. Once the Transfer Cask /DSC has been removed from the Spent Fuel Pool, 60 gallons of water is removed from the DSC. This creates a 4-inch air space below the
-1
NITACHMENT f1)
= Response to the NRC's November 17,1997, Request for AdditionalInformation Regarding Balletin 96-04," Chemical, Galvanic, or other Reactions in Spent Fuel Storage and Transportation Casks"
' Shield Plug. A 1/4 inch tube is then insened into the Vent Port approximately 12 inches.
Inserting the tube 12 inches allows the air space below the Shield Plug to be directly samp'ed. A gas monitor capable et detecting hydrogen gas is then connected to the tube.
The monitor is calibrated per Calven Cliffs calibration procedures. From this point in the loading activity until the Onal Shield Plug weld passes the dye penetrate test, the monitor continually samples the DSC air space. Operators also monitor the 1/4-inch tube for water bubbles that may slow or stop the air Dow, in addition, during welding or cutting processes, an inert cover gas is used to cover the Dame area of the welding and cutting machine. The combination of an inert cover gas and an open vent line during a welding or cutting operation signincantly reduces the likelihood of any hydrogen buildup or ignition.
2.
In our August 19,1996, response to Bulletin 96-04 (Reference 2), we had conservatively set 50% of the lower Dammability limit of hydrogen as the safe upper limit before and during welding or cutting operations. The 50% limit was based on the fact that we were only planning to sample a number of DSC operations involving carbon steel coated with flame-sprayed aluminum, and reevaluate the situation whether to continue sampling. As discussed above, since we are now committed to continuously monitor hydrogen concentration in all DSCs with Game-sprayed aluminum, we have adopted VECTRA's recommendation of 60% of the lower flammability limit of hydrogen (i.e.,2.4% hydrogen by volume) as a safe upper limit before and during welding or cutting operations.
3.
As we stated in our August 19,1996 response to Bulletin 96-04 (Reference 2), if the safe upper limit is exceeded, all welding or cutting operations will be stopped and the DSC air space will be purged. Pmging will be done with Ultered plant air, The DSC air space will be retested for presence of hydrogen before restartn.g any welding or cutting operation,
REFERENCES:
(1)
Letter from Ms. M. G. Bailey (NRC) to Mr. C.11. Cruse (DGE), dated November 17, 1997, Request for Additional Information Based on the N wicar Regulatory Commission's Acceptance of VECTRA Technolcgies' Response to NRC Bulletin 96-04 (2)
Letter from Mr. C.11. Cruse (BGE) to NRC Document Control Desk, dated August 19,1996, Response to NRC Bulletin 96-04: Chemical, Galvanic, or other Reactions in Spent Fuel Storage and Transportation Casks 2
-