ML19211B947
| ML19211B947 | |
| Person / Time | |
|---|---|
| Issue date: | 09/20/1979 |
| From: | Rachel Johnson Office of Nuclear Reactor Regulation |
| To: | Kapo P Office of Nuclear Reactor Regulation |
| References | |
| REF-GTECI-A-11, REF-GTECI-RV, TASK-A-11, TASK-OR NUDOCS 8001070231 | |
| Download: ML19211B947 (3) | |
Text
.
pP # f C go
,h[I [lf
[&
UNITED STATES
^,,
NUCLEAR REGULATORY COMMISSION
%w g
A
..E WASHINGTON, D. C. 20555 o, g "n
g SEP 2 01979
%...+ /
Generic Task No. A-ll MEMORANDUM FOR:
Peter Kapo Reactor Safety Branch Division of Operating Reactors FROM:
R. Johnson, TAP A-ll Manager Engineering Branch Division of Operating Reactors
SUBJECT:
NEUTRON RADIATION SUBTASK SCOPE The purpose of this memorandum is two-fold. First, to report to you the conclusions reached from talking to cognizant people about the dosimetry benchmark experiment at ANO-1. Second, to put down on paper my thoughts on what should go into the A-ll NUREG with respect to neutron radiatiori.
Your response to both is solicited.
1.
Dosimetry Benchmark Under RES/NRC sponsorship, dosimeters were irradiated in the ANO-1 cavity. The data now are all available from Bureau of Standards (Grundl), all traceable to a standard source and ready to be used to evaluate neutron population calculations. Everycne I have talked to agree that the data should be the most accurate to date and as good as the technology can provide.
Serpan (RES) met with me on September 11, 1979; that talk and previous conversations with him and others, especially Morris (00R) led to the following conclusions.
a.
B&W i: ready and able to perform a calculation for comparison with Grundl's data.
b.
The results of such a comparison would enhance the A-ll NUREG.
If BNL were to perform the same calculation, the expected results c.
would not be significantly different from those of B&W (C.E. and Westinghouse, given the core and dimensional data, also would be expected to produce about the same result).
d.
Some points made by Morris, not exactly concurred in by Serpan were:
(1) comparison of calculations to experiment at one place such as ANO-1 cannot provide a categorical evaluation of all vendors' accur-acies (2) the results from the several benchmark experiment / calculation comparisons should be available before the NRC goes on record with a position (as in the A-ll NUREG).
1739 334 6001070
s Petdr Kapo.
B&W reported the following. Chuck Whitmarsh is working with Grund1 and will provide calculations for comparison with the ANO-1 cavity Because he must model the dosimetry capsule in some dosimetry data.
detail, the task is estimated at about 400 man-hours (about $17K) and will not be complete until March, 1980. Art Lowe (B&W) also noted that the results for the AND-1 rpv surveillance capsule location are available and the comparison of calculated and measured flux there showed agreement to within about 15%. Lowe will keep us informed of further B&W activities relative to the benchmark problem.
In my opinicn, the A-ll NUREG should include a discussion of all the ongoing benchmark experiments (the makeup, schedule and goal oTeach),
what they will supply, cumulatively, to the industry and why they are important to the vessel safety margin problem.
If you agree with this, tell me who will write the discussion and provide a time-table (outline complete; draft complete; final text complete).
2.
A-ll NUREG Input in addition to the above dosimetry benchmark discussion, my suggestions on input to the A-11 NUREG include the following.
The importance of knowing neutron radiation values in the evaluation a.
of operating rpv mechanical properties must be noted.
b.
We need to address the accuracy of energy dependent neutron flux; how accurate are current results, what is underway to firm up our assessment of accuracy and what will improve it in the near term?
Similar statements should be made with respect to the correlations c.
between given fluence results and mechanical properties except that we must avoid unnecessary attention to vessel steel inhomogeneity or whatever else has contributed to scatter in past correlations.
d.
For the purposes of TAP A-ll, we must be satisfied with state-of-the-art' fluence determinations (both calculations and dosimetry) as will also be our attitude toward. stress analysis.
The ongoing efforts in the field should be catalogued to the extent of e.
stating what each task is, when it is to be done and in what way it will improve neutron radiation evaluations.
Completion of the User Request letter, DDR to RES, addressing Serpan's neutron radiation programs, which was assigned you at the meeting in Hanauer's office on August 30, should provide a good foundation for the NUREG write-up. You might reconsider the outline of neutron radiation problem areas we came up with back on August 16 and go with it or modify it if you feel the urge.
In case you did not retain it:
1739 335
s f.E F 2 0 Ts 3 Peter Kapo 1.
Flux Calculation Methods la math models 1b cross-sections 2.
Dosimetry 2a reference standards 2b precision 2c reliability 2d accuracy 3.
Dose Rate Effects 3a concurrent annealing 3b saturation (?)
4.
Neutron Spectrum Effects W
Cmc Richard E. Johnso, TAP A-ll Manager Engineering Branch Division of Operating Reactors
- 5. Hanauer /
cc:
M. Aycock D. Eisenhut V. Noonan L. Shao J. Strosnider R. Gamble l[39 336 W. Morris R. Klecker W. Hazelton J. Knight P. Check S. Pawlicki W. Regan J. Watt S. Varga P. Randall, OSD C. Serpan, RES P. Leech EP2/DSE