ML20079B309
| ML20079B309 | |
| Person / Time | |
|---|---|
| Site: | 052***** |
| Issue date: | 01/02/1995 |
| From: | Fletcher M AECL TECHNOLOGIES |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| RTR-NUREG-CR-6257 NUDOCS 9501050411 | |
| Download: ML20079B309 (3) | |
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AECL Technologies Inc.
9210 Corporate Boulevard Suite 410 Rockville, Maryland 20850 USA 1-800-USA-AECL (301) 417-0047 Fax (301) 417-0746 relex 403-442 January 2,1995 Docket No. STN-52-005 File No. 09000401 Control No. 950102001 i
Document Control Desk U.S. Nuclear Regulatory Commission Mail Station P1-137 Washington, DC 20555
Subject:
Review of Draft NUREG/CR-6257, CANDU 3 Transient Analysis Using Atomic Energy of Canada Ltd. Codes 1
Reference:
NRC letter to AECL Technologies (G. H. Marcus to A. D. Hink) dated December 9,1994: Proprietary Review of Draft NUREG-NUREG/CR-6257 i
Gentlemen:
AECL Technologies Inc. (AECLT) has completed a review of draft NUREG/CR-6257 as requested in the reference. The report contains no information that is considered proprietary. Miscellaneous technical and editorial comments are provided in the enclosure for your consideration.
Should you have any questions regarding this information, please contact the undersigned.
Very truly yours, M. H. Fle cher Director Safety & Licensing, AECL Technologies Inc.
Enclosure cc:
D. Scaletti NRR CANDUin the USA 9501oso421 950102
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PDR ADDCK 052*****-
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Document Control Desk Control No. 950102001 1
Enclosure, Page 1 of 2 Miscellaneous Comments 1.
Preface, Para.1 - The last sentence makes a statement regarding the degree of validation of AECL codes that is not supported in the report. The basis for the statement should be provided.
2.
Preface, Para. 4 - Since the discussion pertains to low probability events, the availability of the reactor regulating system mechanical control absorber (MCA) rods should be mentioned. The MCAs can assure reactor shutdown for many events without recourse to Shutdown Systems 1 and 2.
3.
Preface, Para. 5 - Many of the event sequences that are addressed in this report are of sufficiently low probability that they should be considered neither design basis nor severe accidents but, rather, " residual risk" events.
4.
Page 3, Section 2, Para. 9 - The containment design pressure is set by the iarge LOCA with Loss of ECC event.
5.
Page 4, Table 1 - The heat transport system (HTS) pumps are of single suction, single discharge design.
6.
Page 10, Table 3 - The footnote should address heat losses, not head losses.
7.
Page 11, Para.1 - Wording clarifications are needed. The HTS pumps have an automatic trip that occurs 15 minutes following a LOCA signal. The LOCA signal is generated by low outlet header pressure (6 MPa) together with one of two conditioning signals: high containment pressure or sustained low -
header pressure. Although the reactor building pressure was not modelled by CATHENA, that conditioning signal was employed for all LOCAs larger than 0.76% RIH size.
8.
Page 19, Section 4.1, last sentence - Since the discussion pertains to low probability events, the availability of the reactor regulating system mechanical control absorber (MCA) rods should be mentioned. The MCAs can assure reactor shutdown for many events without recourse to Shutdown Systems 1 j
and 2.
9.
Page 19, Section 4.1.1, 4th sentence - This statement implies that all possible c
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Document Control Desk Control No. 950102001 Enclosure, Page 2 of 2 i
SDS 1 and SDS 2 trip parameters were evaluated. It appears that the L
parametera should be limited to those in Table 6.
i.
10.
Page 39, Section 4.3, Para.1 - The mechanical zone controllers. (MZCs) for i
CANDU 3 are tubular neutron absorbing rods not light water-filled tubes. A setback to 60% power is effected by the MZCs and MCAs.
t 11.
Page 39, Section 4.3, Para. 5 - For clarity, the list of five cases examined should state that each case assumes no action from SDS 2.
12.
Page 70,- Para. 2 - Wording clarification is suggested. It is implied that the scram signal occurs after the LOCA signal. However, as stated on page 64, the scram signal occurs at about 177 sec.; and the LOCA signal at about 500 t
sec.
13.
Section 6 - Reference 4 should be dated October 25,1991.
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