ML042950151
| ML042950151 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 10/20/2004 |
| From: | Hartz L Dominion Nuclear Connecticut |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 04-607 | |
| Download: ML042950151 (11) | |
Text
Dominion Nuclear Connecticut, Inc.
Millstone Powcr Station Kopc Fury I<o,id W.irerforci, 06385 October 20, 2004 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555 k
v borninion Serial No.:
04-607 NLOS/PRW Rev. 0 Docket No.:
50-423 License No.:
NPF-49 DOMINION NUCLEAR CONNECTICUT, INC.
MILLSTONE POWER STATION UNIT 3 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING PROPOSED TECHNICAL SPECIFICATION CHANGES FOR IMPLEMENTATION OF ALTERNATE SOURCE TERM In a letter dated May 27, 2004, Dominion Nuclear Connecticut, Inc. (DNC) requested an amendment in the form of changes to the Technical Specifications to Facility Operating License Number NPF-49 for Millstone Power Station Unit 3. The proposed changes were requested based on the radiological dose analysis margins obtained by using an alternate source term consistent with 10 CFR 50.67. In a facsimile dated August 20, 2004, the NRC requested additional information to facilitate the technical review being conducted by the staff. In a letter dated September 27, 2004, DNC forwarded the response to the request for additional information.
In a facsimile dated September 22, 2004, the NRC forwarded a second request for additional information. Attachment 1 of this letter provides the response to the request for additional information.
In accordance with 10 CFR 50.91 (b), a copy of this License Amendment Request is being provided to the State of Connecticut.
If you should have any questions regarding this submittal, please contact Mr. Paul R.
Willoughby at (804) 273-3572.
Very truly yours, Leslie N. Hartz Vice President - Nuclear Engineering Attachment Commitments made in this letter: None.
Serial No.: 04-607 Docket No.: 50-423 Page 2 of 3 cc:
U. S. Nuclear Regulatory Commission Region I 475 Allendale Road King of Prussia, PA 19406-1 41 5 Mr. V. Nerses Senior Project Manager U. S. Nuclear Regulatory Commission One White Flint North 1 1555 Rockville Pike Mail Stop 8C2 Rockville, MD 20852-2738 Mr. S. M. Schneider NRC Senior Resident Inspector Millstone Power Station Director Bureau of Air Management Monitoring & Radiation Division Department of Environmental Protection 79 Elm Street Hartford, CT 061 06-5127
Serial No.: 04-607 Docket No.: 50-423 Page 3 of 3 COMMONWEALTH OF VIRGINIA
)
)
COUNTY OF HENRICO
)
The foregoing document was acknowledged before me, in and for the County and Commonwealth aforesaid, today by Leslie N. Hartz, who is Vice President - Nuclear Engineering of Dominion Nuclear Connecticut, Inc. She has affirmed before me that she is duly authorized to execute and file the foregoing document in behalf of that company, and that the statements in the document are true to the best of her knowledge and belief.
m
,2004.
Acknowledged before me this 20 = day of o&h4, My Commission Expires:
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f3y///
Notary Public (SEAL)
Serial No.: 04-607 Docket No.: 50-423 ATTACHMENT 1 PROPOSED TECHNICAL SPECIFICATION CHANGES IMPLEMENTATION OF ALTERNATE SOURCE TERM RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION DOMINION NUCLEAR CONNECTICUT, INC.
MILLSTONE POWER STATION UNIT 3
Serial Docket NO.: 04-607 NO.: 50-423 Page 1 of 3 PROPOSED TECHNICAL SPECIFICATION CHANGES IMPLEMENTATION OF ALTERNATE SOURCE TERM RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION In a letter dated May 27, 2004, Dominion Nuclear Connecticut, Inc. (DNC) requested an amendment in the form of changes to the Technical Specifications to Facility Operating License Number NPF-49 for Millstone Power Station Unit 3. The proposed changes were requested based on the radiological dose analysis margins obtained by using an alternate source term consistent with 10 CFR 50.67. In a facsimile dated September 22, 2004, the NRC requested additional information to facilitate the technical review being conducted by the staff to clarify certain items of the May 27, 2004 submittal.
Below is the response to the request for additional information:
NRC Background Statement The license amendment request (LAR) identifies a proposed volume quench spray (QS) coverage of 49.63% starting at 72.5 sec and lasting to (or for) 7480 sec. The current QS (FSAR) coverage is 50.27%.
In addition, the LAR proposes to credit the effectiveness of the recirculation spray (RS), at 840 sec (starts at 660 sec) increasing the volume coverage to 64.5% when the RS becomes effective. After the QS is secured, even though the RS continues, no credit is taken for iodine removal.
NRC Question 1 It appears that the reduced QS coverage is a result of the identified change in the containment free volume from 2. 3 2 ~ 1 0 ~
to 2.35~10 ft (LAR Table 2.6-1). That is the sprayed volume remains the same at about 1,166,200 ft3 and with the increased free volume considered to be part of the unsprayed volume the QS sprayed volume percentage is reduced.
6 3
Provide a reference to the revised containment free volume calculation and summarize the basis for the new volume value and spray coverage value.
DNC Response Calculation 121 79-ES-227, Revision 0, dated 02/04/80 is the basis for the containment free volume. This calculation indicates that the maximum free volume is 2.35 XI0 ft.
This value was utilized in the current analysis since use of the maximum containment free volume results in a larger unsprayed volume. The containment free volume previously used (i.e. 2.32 XI0 ft ) is a value within the range of containment free volume calculated in Calculation 121 79-ES-227, Revision 0. The difference between the two volumes (i.e. 0.03 X 10 ft ) has been categorized as unsprayed volume in the current submittal.
6 3
6 3
6 3
Serial No.: 04-607 Docket No.: 50-423 Page 2 of 3 Calc note 369:
Zone I
I1 Ill Total LAR forAST QS QS + RS RS The basis for the Quench Spray System (QSS) spray coverage percentage is unchanged from the current and previously approved spray coverage basis. First the QSS sprayed volume above the operating deck is determined. This volume is equal to the area inside the crane wall from the operating deck at elevation 51 - 4 to the upper QSS ring header at elevation 168 - 0. This volume is reduced by approximately 12%
to account for equipment present in the QSS sprayed volume above the operating deck.
There are several spaces inside the crane wall and below the operating deck that are sprayed. The spaces include: 1) the refueling cavity volume, 2) the refueling canal volume, 3) the hoist space volumes and 4) steam generator cubicle volumes. These volumes are added to the free volume above the operating deck, but below the QSS spray ring at elevation 168- 0 to determine the QSS sprayed volume. The QSS sprayed volume is then divided by the maximum containment free volume to determine the QSS spray coverage percentage.
v, =
v, =
Total (ft3)
Sprayed Unsprayed 465,269 253,108 718,377 259,005 191,870 450,875 71,097 1,109,651 1,180,748 795,371 1,554,629 2,350,000 1,166,200 1,183,800 2,350,000 1 3 1 5,858 834,142 2,350,000 A 349,658 A -349,568 0
(ft )
(ft3)
NRC Question 2 The staff reviewed Quench Spray Coverage calculation 08506 US(9)-369 dated 511 9/99 as background material on how the coverage was calculated. This appears to yield a QS coverage fraction of 33.85%, as summarized in this table (with added for clarification - QS LAR is 49.63%):
the LAR values nla or the Radiological Provide a description, or the calculation title, of the QS LAR volume coverage fraction in sufficient detail to understand the volume values and the QS coverage fractions, and to what extent, if any, the values derived are considered to be conservative for the intended use.
The current FSAR calculation would be sufficient if the staffs interpretation of the reduced LAR value is correct. If the methodology employed in calculation 369 was used, describe the difference in sufficient detail to understand the new QS value.
Serial No.: 04-607 Docket No.: 50-423 Page 3 of 3 DNC Response The methodology utilized in Calculation US(B)-369 was not used. The methodology used is consistent with the current plant license. This methodology is documented in Calculation US(B)-341. The Calculation US(B)-341 methodology is described above in the response to Question 1. Conservatisms present in the calculation include application of the maximum containment free volume and no credit for QSS spray reaching certain portions of containment (e.g. containment annulus area). An example calculation of the QSS sprayed volume percentage is provided in Enclosure 1.
NRC Question 3 The LAR proposes to credit the RS.
Provide a description, or the calculation file, of the RS LAR volume coverage fraction in sufficient detail to understand the volume values and the RS coverage fractions, and to what extent, if any, the values derived are considered to be conservative for the intended use. If the methodology employed in calculation 369 was used, describe the difference in sufficient detail to understand the RS value.
DNC Response The methodology utilized in Calculation US(B)-369 was not used. The methodology used in calculating the sprayed volume is consistent with the methodology utilized in Calculation US(B)-341. Only the combined spray coverage for the Recirculation Spray System (RSS) and QSS is credited in the analysis. As discussed in the introduction of the RAI, after QSS is secured, even though the RSS continues to operate, no credit is taken for iodine removal.
An RSS alone spray coverage volume has not been determined or used. Relative to the RSS and QSS spray coverage, this methodology is documented in Calculation US( B)-341. The Calculation US(B)-341 methodology is similar to that described in the response to Question 1 for QSS. The RSS headers are physically located above the crane wall. A significant portion of the RSS spray will fill the containment annulus area (i.e. the area between the outside of the crane wall and the containment liner). A 50% spray coverage factor is used for the containment annulus area. This factor includes congestion for equipment. Conservatisms present in the calculation include application of the maximum containment free volume and no credit for either RSS or QSS spray reaching certain portions of containment (e.g. a significant portion of the containment annulus area). An example calculation of the RSS and QSS sprayed volume is provided in Enclosure 1.
Serial No.: 04-607 Docket No.: 50-423 ENCLOSURE 1 PROPOSED TECHNICAL SPECIFICATION CHANGES IMPLEMENTATION OF ALTERNATE SOURCE TERM QSS SPRAYED VOLUME PERCENTAGE RSS AND QSS SPRAYED VOLUME DOMINION NUCLEAR CONNECTICUT, INC.
MILLSTONE POWER STATION UNIT 3
Serial No.04-607 Page 1 of 3 V (containment Quench SDrav Svstem sDraved volume):
The containment sprayed volume is V = 1,166,200 ft3. (See the following pages for derivation)
The containment sprayed volume was determined as documented below:
L Inside Top of Dome h
+
I Operating Deck 51 - 4 4-,
Bend Line El 104 I \\
40 Note: The inside crane wall diameter specified is for elevations below the operating deck elevation of 51 - 4. The crane wall inside diameter is 1 10 from elevation 51 - 4 and hiaher v
This calculation utilizes the smaller more conservative diameter of 109 The congestion factor for the containment volume is determined below (Reference Calculation ES-227, page 178):
Congestion Factor = Volume of Containment Internal Structures (etc.)
Gross Containment Volume
= 3.13 x lo5 = 12%
2.62 X lo6 Determination of h:
n A2 + B2 = C2 C = 70 A =.I C2 - B2 Bend Line
= 44 B = 54.5 h = 44 + (104 - 51.33)
= 96.67 V1 = n *
- h = 7c
- 1092
- 96.67 = 902,000 ft3 (Volume of a right cylinder) 4 4
Serial No.04-607 Page 2 of 3 Height of Volume V2 (h2):
QSS Upper Header Elevation - (Operating Deck Elevation + h) 168 - (51.33 + 96.67) = 20 Radius of Upper Horizontal Circular Surface, R2 (QSS Upper Header - Bend Line)
R2 =.I 70 - 642
= 28.4 I
\\
V2 = 1/6
- x
- 20 * [(3 * (514.5)~
+ 3 * (28.4)2 + (20)2] = 122,800 ft3 Therefore, the total sprayed volume above the operating deck is equal to:
(V, + V2) * (100% - containment congestion factor)
= (902,000 + 122,800)
- (0.88) = 902,000 ft3 Additional volumes are sprayed below the operating deck at elevation 51 - 4. These additional sprayed volumes are summarized below:
The steam generator cubicles from 3 - 8, refueling cavity and canal, and hoist space down to 3
- 8.
Refueling cavity volume Refueling canal volume Hoist space Hoist space Steam generator A Steam generator B Steam generator C Steam qenerator D Total
= 40,164
= 6,133
= 13,417
= 10,813
= 49,501
= 47334
= 47334
= 49,501
= 264,200ft3
Serial No.04-607 Page 3 of 3 Grand total of Quench Sprav Svstem spraved volume = 902,000 + 264,200 = 1,166,200 ft3 Dividing by the total volume (Reference Calculation ES-227) of 2.35 x 1 O6 ft3 yields a QSS spraved volume percentacae of: 49.63%.
RSS and QSS Spraved Volume The two recirculation spray headers are located at elevation 141 - 9 and 145 - 3. The two headers are positioned nearly over the containment crane wall. The spray pattern of the recirculation spray results in spray coverage of the containment annulus area (i.e. coverage of the area between the crane wall and the containment exterior wall). An estimate of the spray coverage area is estimated to be 50% of the annulus area from the elevation of the crane wall to the containment mat (including a the congestion factor).
Top of Crane Wall EL
+
105 - 7 Mat High Point EL
+
I-) 24 - 6 Annulus Height
+
130 - 1 Containment Inside Radius 3 70.0 Crane Wall Outside Radius +
57.5 = 55 + 2.5 The recirculation spray coverage of the annulus area is estimated to be:
Il x (702 - 57.52) x 130.08 x 50% = 325650 ft3 The recirculation spray coverage above the crane wall is:
II x (57.52 - 55.02) x (1 45.25 - 105.58) = 35140 ft3 The total recirculation spray coverage is:
325650 + 351 40 = 360790 ft3 The combined RSS and QSS spraved volume is:
1 166200 + 360790 = 1526990 ft3 Note the RSS and QSS spray coverage volume of 1,515,858 ft3 was conservatively used in the analysis.