# Problem with downloading ENDFB-8.0-NNDC **URL:** \ **Category:** User Support\ **Created:** [July 12, 2024, 11:43am UTC](https://openmc.discourse.group/t/problem-with-downloading-endfb-8-0-nndc/4560 "2024-07-12T11:43:09Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![zeinab\_mdi70](https://avatars.discourse-cdn.com/v4/letter/z/22d042/32.png) [@zeinab\_mdi70](https://openmc.discourse.group/u/zeinab_mdi70)\ **Post date:** [July 12, 2024, 11:43am UTC](https://openmc.discourse.group/t/problem-with-downloading-endfb-8-0-nndc/4560/1 "2024-07-12T11:43:09Z")
Hello everybody. I’m encountering an issue while trying to download ENDF/B 8.0-NNDC data using the `openmc_data_downloader`. When I attempt to download this specific library, the process fails, whereas downloading other libraries such as ENDF/B 7.1-NNDC works without any issues. I use this : lib = “ENDFB-8.0-NNDC” ## mats.download\_cross\_section\_data( libraries=[lib], set\_OPENMC\_CROSS\_SECTIONS=True, particles=[“neutron”], ) And the error is: OSError Traceback (most recent call last) Cell In[3], line 34 29 # lib= “FENDL-3.1d” # does not contain cross sections at the right energy 30 #lib=“ENDFB-7.1-NNDC” # does not contain cross sections at the right energy 31 # lib=“TENDL-2019” # does not contain cross sections at the right energy 32 lib = “ENDFB-8.0-NNDC” # this one works 🙂 —\> 34 mats.download\_cross\_section\_data( 35 libraries=[lib], 36 set\_OPENMC\_CROSS\_SECTIONS=True, 37 particles=[“neutron”], 38 ) File ~/micromamba/envs/demosim/lib/python3.9/site-packages/openmc\_data\_downloader/utils.py:148, in download\_cross\_section\_data(self, libraries, destination, particles, set\_OPENMC\_CROSS\_SECTIONS, overwrite) 142 print(dataframe) 144 download\_data\_frame\_of( 145 dataframe=dataframe, destination=destination, overwrite=overwrite 146 ) → 148 cross\_section\_xml\_path = create\_cross\_sections\_xml(dataframe, destination) 150 if set\_OPENMC\_CROSS\_SECTIONS is True: 151 self.cross\_sections = cross\_section\_xml\_path File ~/micromamba/envs/demosim/lib/python3.9/site-packages/openmc\_data\_downloader/utils.py:246, in create\_cross\_sections\_xml(dataframe, destination) 244 for index, row in dataframe.iterrows(): 245 if destination is None: → 246 library.register\_file(Path(row[“local\_file”])) 247 else: 248 library.register\_file(Path(destination) / Path(row[“local\_file”])) File ~/micromamba/envs/demosim/lib/python3.9/site-packages/openmc/data/library.py:91, in DataLibrary.register\_file(self, filename) 89 materials = 90 elif path.suffix == ‘.h5’: —\> 91 with h5py.File(path, ‘r’) as h5file: 92 filetype = h5file.attrs[‘filetype’].decode()[5:] 93 materials = list(h5file) File ~/micromamba/envs/demosim/lib/python3.9/site-packages/h5py/\_hl/files.py:562, in File. **init** (self, name, mode, driver, libver, userblock\_size, swmr, rdcc\_nslots, rdcc\_nbytes, rdcc\_w0, track\_order, fs\_strategy, fs\_persist, fs\_threshold, fs\_page\_size, page\_buf\_size, min\_meta\_keep, min\_raw\_keep, locking, alignment\_threshold, alignment\_interval, meta\_block\_size, \*\*kwds) 553 fapl = make\_fapl(driver, libver, rdcc\_nslots, rdcc\_nbytes, rdcc\_w0, 554 locking, page\_buf\_size, min\_meta\_keep, min\_raw\_keep, 555 alignment\_threshold=alignment\_threshold, 556 alignment\_interval=alignment\_interval, 557 meta\_block\_size=meta\_block\_size, 558 \*\*kwds) 559 fcpl = make\_fcpl(track\_order=track\_order, fs\_strategy=fs\_strategy, 560 fs\_persist=fs\_persist, fs\_threshold=fs\_threshold, 561 fs\_page\_size=fs\_page\_size) → 562 fid = make\_fid(name, mode, userblock\_size, fapl, fcpl, swmr=swmr) 564 if isinstance(libver, tuple): 565 self.\_libver = libver File ~/micromamba/envs/demosim/lib/python3.9/site-packages/h5py/\_hl/files.py:235, in make\_fid(name, mode, userblock\_size, fapl, fcpl, swmr) 233 if swmr and swmr\_support: 234 flags |= h5f.ACC\_SWMR\_READ → 235 fid = h5f.open(name, flags, fapl=fapl) 236 elif mode == ‘r+’: 237 fid = h5f.open(name, h5f.ACC\_RDWR, fapl=fapl) File h5py/\_objects.pyx:54, in h5py.\_objects.with\_phil.wrapper() File h5py/\_objects.pyx:55, in h5py.\_objects.with\_phil.wrapper() File h5py/h5f.pyx:102, in h5py.h5f.open() OSError: Unable to synchronously open file (truncated file: eof = 66095922, sblock-\>base\_addr = 0, stored\_eof = 168251464) Thank you in advance ---
**Author:** ![Shimwell](https://yyz2.discourse-cdn.com/free1/user_avatar/openmc.discourse.group/shimwell/32/3876_2.png) [@Shimwell](https://openmc.discourse.group/u/Shimwell)\ **Post date:** [July 15, 2024, 11:03pm UTC](https://openmc.discourse.group/t/problem-with-downloading-endfb-8-0-nndc/4560/2 "2024-07-15T23:03:01Z")
I’m not able to reproduce the error, the download command for endf 8.0 appears to work over here ![Screenshot from 2024-07-16 01-00-09](https://global.discourse-cdn.com/free1/uploads/openmc/original/2X/9/92e8393d8f773d743b403d79bbcef60323d6ab58.png) `openmc_data_downloader -l ENDFB-8.0-NNDC -i Fe56 Be9 Li6 Li7 H1 H2`